JIRA: https://issues.redhat.com/browse/RHEL-77358
commit a065bbf776d32a71e748bd948861e6deca803d78
Author: Tomas Glozar <tglozar@redhat.com>
Date: Mon Feb 3 10:04:18 2025 +0100
trace/osnoise: Add trace events for samples
Add trace events that fire at osnoise and timerlat sample generation, in
addition to the already existing noise and threshold events.
This allows processing the samples directly in the kernel, either with
ftrace triggers or with BPF.
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Link: https://lore.kernel.org/20250203090418.1458923-1-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Tested-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-65271
CVE: CVE-2024-49866
commit 829e0c9f0855f26b3ae830d17b24aec103f7e915
Author: Wei Li <liwei391@huawei.com>
Date: Tue Sep 24 17:45:13 2024 +0800
tracing/timerlat: Fix a race during cpuhp processing
There is another found exception that the "timerlat/1" thread was
scheduled on CPU0, and lead to timer corruption finally:
```
ODEBUG: init active (active state 0) object: ffff888237c2e108 object type: hrtimer hint: timerlat_irq+0x0/0x220
WARNING: CPU: 0 PID: 426 at lib/debugobjects.c:518 debug_print_object+0x7d/0xb0
Modules linked in:
CPU: 0 UID: 0 PID: 426 Comm: timerlat/1 Not tainted 6.11.0-rc7+ #45
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:debug_print_object+0x7d/0xb0
...
Call Trace:
<TASK>
? __warn+0x7c/0x110
? debug_print_object+0x7d/0xb0
? report_bug+0xf1/0x1d0
? prb_read_valid+0x17/0x20
? handle_bug+0x3f/0x70
? exc_invalid_op+0x13/0x60
? asm_exc_invalid_op+0x16/0x20
? debug_print_object+0x7d/0xb0
? debug_print_object+0x7d/0xb0
? __pfx_timerlat_irq+0x10/0x10
__debug_object_init+0x110/0x150
hrtimer_init+0x1d/0x60
timerlat_main+0xab/0x2d0
? __pfx_timerlat_main+0x10/0x10
kthread+0xb7/0xe0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x2d/0x40
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
```
After tracing the scheduling event, it was discovered that the migration
of the "timerlat/1" thread was performed during thread creation. Further
analysis confirmed that it is because the CPU online processing for
osnoise is implemented through workers, which is asynchronous with the
offline processing. When the worker was scheduled to create a thread, the
CPU may has already been removed from the cpu_online_mask during the offline
process, resulting in the inability to select the right CPU:
T1 | T2
[CPUHP_ONLINE] | cpu_device_down()
osnoise_hotplug_workfn() |
| cpus_write_lock()
| takedown_cpu(1)
| cpus_write_unlock()
[CPUHP_OFFLINE] |
cpus_read_lock() |
start_kthread(1) |
cpus_read_unlock() |
To fix this, skip online processing if the CPU is already offline.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240924094515.3561410-4-liwei391@huawei.com
Fixes: c8895e271f ("trace/osnoise: Support hotplug operations")
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-65271
commit b484a02c9cedf8703eff8f0756f94618004bd165
Author: Wei Li <liwei391@huawei.com>
Date: Tue Sep 24 17:45:12 2024 +0800
tracing/timerlat: Drop interface_lock in stop_kthread()
stop_kthread() is the offline callback for "trace/osnoise:online", since
commit 5bfbcd1ee57b ("tracing/timerlat: Add interface_lock around clearing
of kthread in stop_kthread()"), the following ABBA deadlock scenario is
introduced:
T1 | T2 [BP] | T3 [AP]
osnoise_hotplug_workfn() | work_for_cpu_fn() | cpuhp_thread_fun()
| _cpu_down() | osnoise_cpu_die()
mutex_lock(&interface_lock) | | stop_kthread()
| cpus_write_lock() | mutex_lock(&interface_lock)
cpus_read_lock() | cpuhp_kick_ap() |
As the interface_lock here in just for protecting the "kthread" field of
the osn_var, use xchg() instead to fix this issue. Also use
for_each_online_cpu() back in stop_per_cpu_kthreads() as it can take
cpu_read_lock() again.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240924094515.3561410-3-liwei391@huawei.com
Fixes: 5bfbcd1ee57b ("tracing/timerlat: Add interface_lock around clearing of kthread in stop_kthread()")
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-65271
commit 0bb0a5c12ecf36ad561542bbb95f96355e036a02
Author: Wei Li <liwei391@huawei.com>
Date: Tue Sep 24 17:45:11 2024 +0800
tracing/timerlat: Fix duplicated kthread creation due to CPU online/offline
osnoise_hotplug_workfn() is the asynchronous online callback for
"trace/osnoise:online". It may be congested when a CPU goes online and
offline repeatedly and is invoked for multiple times after a certain
online.
This will lead to kthread leak and timer corruption. Add a check
in start_kthread() to prevent this situation.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240924094515.3561410-2-liwei391@huawei.com
Fixes: c8895e271f ("trace/osnoise: Support hotplug operations")
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-39968
commit af178143343028fdec9d5960a22d17f5587fd3f5
Author: Steven Rostedt <rostedt@goodmis.org>
Date: Mon Sep 9 10:32:31 2024 -0400
tracing/osnoise: Fix build when timerlat is not enabled
To fix some critical section races, the interface_lock was added to a few
locations. One of those locations was above where the interface_lock was
declared, so the declaration was moved up before that usage.
Unfortunately, where it was placed was inside a CONFIG_TIMERLAT_TRACER
ifdef block. As the interface_lock is used outside that config, this broke
the build when CONFIG_OSNOISE_TRACER was enabled but
CONFIG_TIMERLAT_TRACER was not.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Helena Anna" <helena.anna.dubel@intel.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Tomas Glozar <tglozar@redhat.com>
Link: https://lore.kernel.org/20240909103231.23a289e2@gandalf.local.home
Fixes: e6a53481da29 ("tracing/timerlat: Only clear timer if a kthread exists")
Reported-by: "Bityutskiy, Artem" <artem.bityutskiy@intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-39968
commit 5bfbcd1ee57b607fd29e4645c7f350dd385dd9ad
Author: Steven Rostedt <rostedt@goodmis.org>
Date: Thu Sep 5 11:33:59 2024 -0400
tracing/timerlat: Add interface_lock around clearing of kthread in stop_kthread()
The timerlat interface will get and put the task that is part of the
"kthread" field of the osn_var to keep it around until all references are
released. But here's a race in the "stop_kthread()" code that will call
put_task_struct() on the kthread if it is not a kernel thread. This can
race with the releasing of the references to that task struct and the
put_task_struct() can be called twice when it should have been called just
once.
Take the interface_lock() in stop_kthread() to synchronize this change.
But to do so, the function stop_per_cpu_kthreads() needs to change the
loop from for_each_online_cpu() to for_each_possible_cpu() and remove the
cpu_read_lock(), as the interface_lock can not be taken while the cpu
locks are held. The only side effect of this change is that it may do some
extra work, as the per_cpu variables of the offline CPUs would not be set
anyway, and would simply be skipped in the loop.
Remove unneeded "return;" in stop_kthread().
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Link: https://lore.kernel.org/20240905113359.2b934242@gandalf.local.home
Fixes: e88ed227f639e ("tracing/timerlat: Add user-space interface")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-39968
commit e6a53481da292d970d1edf0d8831121d1c5e2f0d
Author: Steven Rostedt <rostedt@goodmis.org>
Date: Thu Sep 5 08:53:30 2024 -0400
tracing/timerlat: Only clear timer if a kthread exists
The timerlat tracer can use user space threads to check for osnoise and
timer latency. If the program using this is killed via a SIGTERM, the
threads are shutdown one at a time and another tracing instance can start
up resetting the threads before they are fully closed. That causes the
hrtimer assigned to the kthread to be shutdown and freed twice when the
dying thread finally closes the file descriptors, causing a use-after-free
bug.
Only cancel the hrtimer if the associated thread is still around. Also add
the interface_lock around the resetting of the tlat_var->kthread.
Note, this is just a quick fix that can be backported to stable. A real
fix is to have a better synchronization between the shutdown of old
threads and the starting of new ones.
Link: https://lore.kernel.org/all/20240820130001.124768-1-tglozar@redhat.com/
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Link: https://lore.kernel.org/20240905085330.45985730@gandalf.local.home
Fixes: e88ed227f639e ("tracing/timerlat: Add user-space interface")
Reported-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-39968
commit 177e1cc2f41235c145041eed03ef5bab18f32328
Author: Steven Rostedt <rostedt@goodmis.org>
Date: Wed Sep 4 10:34:28 2024 -0400
tracing/osnoise: Use a cpumask to know what threads are kthreads
The start_kthread() and stop_thread() code was not always called with the
interface_lock held. This means that the kthread variable could be
unexpectedly changed causing the kthread_stop() to be called on it when it
should not have been, leading to:
while true; do
rtla timerlat top -u -q & PID=$!;
sleep 5;
kill -INT $PID;
sleep 0.001;
kill -TERM $PID;
wait $PID;
done
Causing the following OOPS:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 5 UID: 0 PID: 885 Comm: timerlatu/5 Not tainted 6.11.0-rc4-test-00002-gbc754cc76d1b-dirty #125 a533010b71dab205ad2f507188ce8c82203b0254
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:hrtimer_active+0x58/0x300
Code: 48 c1 ee 03 41 54 48 01 d1 48 01 d6 55 53 48 83 ec 20 80 39 00 0f 85 30 02 00 00 49 8b 6f 30 4c 8d 75 10 4c 89 f0 48 c1 e8 03 <0f> b6 3c 10 4c 89 f0 83 e0 07 83 c0 03 40 38 f8 7c 09 40 84 ff 0f
RSP: 0018:ffff88811d97f940 EFLAGS: 00010202
RAX: 0000000000000002 RBX: ffff88823c6b5b28 RCX: ffffed10478d6b6b
RDX: dffffc0000000000 RSI: ffffed10478d6b6c RDI: ffff88823c6b5b28
RBP: 0000000000000000 R08: ffff88823c6b5b58 R09: ffff88823c6b5b60
R10: ffff88811d97f957 R11: 0000000000000010 R12: 00000000000a801d
R13: ffff88810d8b35d8 R14: 0000000000000010 R15: ffff88823c6b5b28
FS: 0000000000000000(0000) GS:ffff88823c680000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000561858ad7258 CR3: 000000007729e001 CR4: 0000000000170ef0
Call Trace:
<TASK>
? die_addr+0x40/0xa0
? exc_general_protection+0x154/0x230
? asm_exc_general_protection+0x26/0x30
? hrtimer_active+0x58/0x300
? __pfx_mutex_lock+0x10/0x10
? __pfx_locks_remove_file+0x10/0x10
hrtimer_cancel+0x15/0x40
timerlat_fd_release+0x8e/0x1f0
? security_file_release+0x43/0x80
__fput+0x372/0xb10
task_work_run+0x11e/0x1f0
? _raw_spin_lock+0x85/0xe0
? __pfx_task_work_run+0x10/0x10
? poison_slab_object+0x109/0x170
? do_exit+0x7a0/0x24b0
do_exit+0x7bd/0x24b0
? __pfx_migrate_enable+0x10/0x10
? __pfx_do_exit+0x10/0x10
? __pfx_read_tsc+0x10/0x10
? ktime_get+0x64/0x140
? _raw_spin_lock_irq+0x86/0xe0
do_group_exit+0xb0/0x220
get_signal+0x17ba/0x1b50
? vfs_read+0x179/0xa40
? timerlat_fd_read+0x30b/0x9d0
? __pfx_get_signal+0x10/0x10
? __pfx_timerlat_fd_read+0x10/0x10
arch_do_signal_or_restart+0x8c/0x570
? __pfx_arch_do_signal_or_restart+0x10/0x10
? vfs_read+0x179/0xa40
? ksys_read+0xfe/0x1d0
? __pfx_ksys_read+0x10/0x10
syscall_exit_to_user_mode+0xbc/0x130
do_syscall_64+0x74/0x110
? __pfx___rseq_handle_notify_resume+0x10/0x10
? __pfx_ksys_read+0x10/0x10
? fpregs_restore_userregs+0xdb/0x1e0
? fpregs_restore_userregs+0xdb/0x1e0
? syscall_exit_to_user_mode+0x116/0x130
? do_syscall_64+0x74/0x110
? do_syscall_64+0x74/0x110
? do_syscall_64+0x74/0x110
entry_SYSCALL_64_after_hwframe+0x71/0x79
RIP: 0033:0x7ff0070eca9c
Code: Unable to access opcode bytes at 0x7ff0070eca72.
RSP: 002b:00007ff006dff8c0 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 00007ff0070eca9c
RDX: 0000000000000400 RSI: 00007ff006dff9a0 RDI: 0000000000000003
RBP: 00007ff006dffde0 R08: 0000000000000000 R09: 00007ff000000ba0
R10: 00007ff007004b08 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ff006dff9a0 R14: 0000000000000007 R15: 0000000000000008
</TASK>
Modules linked in: snd_hda_intel snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec snd_hwdep snd_hda_core
---[ end trace 0000000000000000 ]---
This is because it would mistakenly call kthread_stop() on a user space
thread making it "exit" before it actually exits.
Since kthreads are created based on global behavior, use a cpumask to know
when kthreads are running and that they need to be shutdown before
proceeding to do new work.
Link: https://lore.kernel.org/all/20240820130001.124768-1-tglozar@redhat.com/
This was debugged by using the persistent ring buffer:
Link: https://lore.kernel.org/all/20240823013902.135036960@goodmis.org/
Note, locking was originally used to fix this, but that proved to cause too
many deadlocks to work around:
https://lore.kernel.org/linux-trace-kernel/20240823102816.5e55753b@gandalf.local.home/
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Link: https://lore.kernel.org/20240904103428.08efdf4c@gandalf.local.home
Fixes: e88ed227f639e ("tracing/timerlat: Add user-space interface")
Reported-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-50869
Conflicts:
Documentation/trace/osnoise-tracer.rst
commit c40583e19eebae50f6b024d8285d2703e2522364
Author: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Date: Mon Jun 10 10:23:14 2024 -0300
rtla/osnoise: set the default threshold to 1us
Change the default threshold for osnoise to 1us, so that any noise
equal or above this value is recorded. Let the user set a higher
threshold if necessary.
Link: https://lore.kernel.org/linux-trace-kernel/Zmb-QhiiiI6jM9To@uudg.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Suggested-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Reviewed-by: Clark Williams <williams@redhat.com>
Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/3462
JIRA: https://issues.redhat.com/browse/RHEL-14932
**Commit List:**
- `e88ed227f639` - [tracing/timerlat: Add user-space interface](COMMIT_LINK_HERE)
- `cb7ca871c883` - [tracing/osnoise: Skip running osnoise if all instances are off](COMMIT_LINK_HERE)
- `4998e7fda149` - [tracing/osnoise: Switch from PF_NO_SETAFFINITY to migrate_disable](COMMIT_LINK_HERE)
**Description:**
This merge request backports the necessary kernel modifications to introduce user-space and cgroup support for the rtla user-space tool. These changes align the rtla kernel base with version v6.4, enabling more robust and versatile performance analysis and monitoring.
**Key Enhancements:**
- A user-space interface for the timerlat tracer is now available, allowing for the rtla tool to also measure latency introduced by userspace.
- Add a cgroup interface to migrate the kthreads to the same cgroup as the userspace tool.
Please review the individual commits for detailed information on the changes and their impact.
Signed-off-by: Chris White <chwhite@redhat.com>
Approved-by: John Kacur <jkacur@redhat.com>
Approved-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Signed-off-by: Scott Weaver <scweaver@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-14932
Upstream Status: v6.4
commit e88ed227f639ebcb31ed4e5b88756b47d904584b
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Tue Jun 6 17:12:27 2023 +0200
tracing/timerlat: Add user-space interface
Going a step further, we propose a way to use any user-space
workload as the task waiting for the timerlat timer. This is done
via a per-CPU file named osnoise/cpu$id/timerlat_fd file.
The tracef_fd allows a task to open at a time. When a task reads
the file, the timerlat timer is armed for future osnoise/timerlat_period_us
time. When the timer fires, it prints the IRQ latency and
wakes up the user-space thread waiting in the timerlat_fd.
The thread then starts to run, executes the timerlat measurement, prints
the thread scheduling latency and returns to user-space.
When the thread rereads the timerlat_fd, the tracer will print the
user-ret(urn) latency, which is an additional metric.
This additional metric is also traced by the tracer and can be used, for
example of measuring the context switch overhead from kernel-to-user and
user-to-kernel, or the response time for an arbitrary execution in
user-space.
The tracer supports one thread per CPU, the thread must be pinned to
the CPU, and it cannot migrate while holding the timerlat_fd. The reason
is that the tracer is per CPU (nothing prohibits the tracer from
allowing migrations in the future). The tracer monitors the migration
of the thread and disables the tracer if detected.
The timerlat_fd is only available for opening/reading when timerlat
tracer is enabled, and NO_OSNOISE_WORKLOAD is set.
The simplest way to activate this feature from user-space is:
-------------------------------- %< -----------------------------------
int main(void)
{
char buffer[1024];
int timerlat_fd;
int retval;
long cpu = 0; /* place in CPU 0 */
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(cpu, &set);
if (sched_setaffinity(gettid(), sizeof(set), &set) == -1)
return 1;
snprintf(buffer, sizeof(buffer),
"/sys/kernel/tracing/osnoise/per_cpu/cpu%ld/timerlat_fd",
cpu);
timerlat_fd = open(buffer, O_RDONLY);
if (timerlat_fd < 0) {
printf("error opening %s: %s\n", buffer, strerror(errno));
exit(1);
}
for (;;) {
retval = read(timerlat_fd, buffer, 1024);
if (retval < 0)
break;
}
close(timerlat_fd);
exit(0);
}
-------------------------------- >% -----------------------------------
When disabling timerlat, if there is a workload holding the timerlat_fd,
the SIGKILL will be sent to the thread.
Link: https://lkml.kernel.org/r/69fe66a863d2792ff4c3a149bf9e32e26468bb3a.1686063934.git.bristot@kernel.org
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: William White <chwhite@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Chris White <chwhite@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-14932
Upstream Status: v6.4
commit cb7ca871c883eed5132e106cda44b2b060e6f52e
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Tue Jun 6 17:12:26 2023 +0200
tracing/osnoise: Skip running osnoise if all instances are off
In the case of all tracing instances being off, sleep for the entire
period.
Q: Why not kill all threads so?
A: It is valid and useful to start the threads with tracing off.
For example, rtla disables tracing, starts the tracer, applies the
scheduling setup to the threads, e.g., sched priority and cgroup,
and then begin tracing with all set.
Skipping the period helps to speed up rtla setup and save the
trace after a stop tracing.
Link: https://lkml.kernel.org/r/aa4dd9b7e76fcb63901fe5407e15ec002b318599.1686063934.git.bristot@kernel.org
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: William White <chwhite@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Chris White <chwhite@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-14932
Upstream Status: v6.4
commit 4998e7fda149d2392ea6aa9879299d8a32019dbe
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Tue Jun 6 17:12:25 2023 +0200
tracing/osnoise: Switch from PF_NO_SETAFFINITY to migrate_disable
Currently, osnoise/timerlat threads run with PF_NO_SETAFFINITY set.
It works well, however, cgroups do not allow PF_NO_SETAFFINITY threads
to be accepted, and this creates a limitation to osnoise/timerlat.
To avoid this limitation, disable migration of the threads as soon
as they start to run, and then clean the PF_NO_SETAFFINITY flag (still)
used during thread creation.
If for some reason a thread migration is requested, e.g., via
sched_settafinity, the tracer thread will notice and exit.
Link: https://lkml.kernel.org/r/8ba8bc9c15b3ea40cf73cf67a9bc061a264609f0.1686063934.git.bristot@kernel.org
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: William White <chwhite@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Chris White <chwhite@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-16305
commit 632478a05821bc1c9b55c3a1dd0fb1be7bfa1acc
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Thu May 11 18:32:01 2023 +0200
tracing/timerlat: Always wakeup the timerlat thread
While testing rtla timerlat auto analysis, I reach a condition where
the interface was not receiving tracing data. I was able to manually
reproduce the problem with these steps:
# echo 0 > tracing_on # disable trace
# echo 1 > osnoise/stop_tracing_us # stop trace if timerlat irq > 1 us
# echo timerlat > current_tracer # enable timerlat tracer
# sleep 1 # wait... that is the time when rtla
# apply configs like prio or cgroup
# echo 1 > tracing_on # start tracing
# cat trace
# tracer: timerlat
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / _-=> migrate-disable
# |||| / delay
# ||||| ACTIVATION
# TASK-PID CPU# ||||| TIMESTAMP ID CONTEXT LATENCY
# | | | ||||| | | | |
NOTHING!
Then, trying to enable tracing again with echo 1 > tracing_on resulted
in no change: the trace was still not tracing.
This problem happens because the timerlat IRQ hits the stop tracing
condition while tracing is off, and do not wake up the timerlat thread,
so the timerlat threads are kept sleeping forever, resulting in no
trace, even after re-enabling the tracer.
Avoid this condition by always waking up the threads, even after stopping
tracing, allowing the tracer to return to its normal operating after
a new tracing on.
Link: https://lore.kernel.org/linux-trace-kernel/1ed8f830638b20a39d535d27d908e319a9a3c4e2.1683822622.git.bristot@kernel.org
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: stable@vger.kernel.org
Fixes: a955d7eac1 ("trace: Add timerlat tracer")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-16305
commit cae16f2c2e11c60c888715f4d98c12740683d6a2
Author: Uladzislau Rezki (Sony) <urezki@gmail.com>
Date: Wed Feb 1 16:08:10 2023 +0100
tracing: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
The kvfree_rcu() macro's single-argument form is deprecated. Therefore
switch to the new kvfree_rcu_mightsleep() variant. The goal is to
avoid accidental use of the single-argument forms, which can introduce
functionality bugs in atomic contexts and latency bugs in non-atomic
contexts.
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-16305
commit d3cba7f02cd82118c32651c73374d8a5a459d9a6
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 29 17:50:16 2023 +0200
tracing/osnoise: Fix notify new tracing_max_latency
osnoise/timerlat tracers are reporting new max latency on instances
where the tracing is off, creating inconsistencies between the max
reported values in the trace and in the tracing_max_latency. Thus
only report new tracing_max_latency on active tracing instances.
Link: https://lkml.kernel.org/r/ecd109fde4a0c24ab0f00ba1e9a144ac19a91322.1680104184.git.bristot@kernel.org
Cc: stable@vger.kernel.org
Fixes: dae181349f1e ("tracing/osnoise: Support a list of trace_array *tr")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-16305
commit b9f451a9029a16eb7913ace09b92493d00f2e564
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 29 17:50:15 2023 +0200
tracing/timerlat: Notify new max thread latency
timerlat is not reporting a new tracing_max_latency for the thread
latency. The reason is that it is not calling notify_new_max_latency()
function after the new thread latency is sampled.
Call notify_new_max_latency() after computing the thread latency.
Link: https://lkml.kernel.org/r/16e18d61d69073d0192ace07bf61e405cca96e9c.1680104184.git.bristot@kernel.org
Cc: stable@vger.kernel.org
Fixes: dae181349f1e ("tracing/osnoise: Support a list of trace_array *tr")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-16305
commit 7a025e066e0f0afd39cc88a089929ccb945ce9e8
Author: Tom Rix <trix@redhat.com>
Date: Thu Mar 9 10:04:14 2023 -0500
tracing/osnoise: set several trace_osnoise.c variables storage-class-specifier to static
smatch reports several similar warnings
kernel/trace/trace_osnoise.c:220:1: warning:
symbol '__pcpu_scope_per_cpu_osnoise_var' was not declared. Should it be static?
kernel/trace/trace_osnoise.c:243:1: warning:
symbol '__pcpu_scope_per_cpu_timerlat_var' was not declared. Should it be static?
kernel/trace/trace_osnoise.c:335:14: warning:
symbol 'interface_lock' was not declared. Should it be static?
kernel/trace/trace_osnoise.c:2242:5: warning:
symbol 'timerlat_min_period' was not declared. Should it be static?
kernel/trace/trace_osnoise.c:2243:5: warning:
symbol 'timerlat_max_period' was not declared. Should it be static?
These variables are only used in trace_osnoise.c, so it should be static
Link: https://lore.kernel.org/linux-trace-kernel/20230309150414.4036764-1-trix@redhat.com
Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-16305
commit 11e4e3523da98c065a6c249013ace0d388e41c25
Author: Cai Huoqing <cai.huoqing@linux.dev>
Date: Fri Jan 14 14:03:06 2022 -0800
trace/osnoise: make use of the helper function kthread_run_on_cpu()
Replace kthread_create_on_cpu/wake_up_process() with kthread_run_on_cpu()
to simplify the code.
Link: https://lkml.kernel.org/r/20211022025711.3673-6-caihuoqing@baidu.com
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Cc: Bernard Metzler <bmt@zurich.ibm.com>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
JIRA: https://issues.redhat.com/browse/RHEL-16305
commit a6ed2aee54644cfa2d04ca86308767f5c3a087e8
Author: Uladzislau Rezki (Sony) <urezki@gmail.com>
Date: Wed Nov 24 12:03:08 2021 +0100
tracing: Switch to kvfree_rcu() API
Instead of invoking a synchronize_rcu() to free a pointer
after a grace period we can directly make use of new API
that does the same but in more efficient way.
Link: https://lkml.kernel.org/r/20211124110308.2053-10-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2174944
commit b18c58af29e465d21d4cd9e8c5008ae0e0147384
Author: Davidlohr Bueso <dave@stgolabs.net>
Date: Mon Jan 23 15:46:49 2023 -0800
tracing/osnoise: No need for schedule_hrtimeout range
No slack time is being passed, just use schedule_hrtimeout().
Link: https://lore.kernel.org/linux-trace-kernel/20230123234649.17968-1-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2174944
commit 685b64e4d6da4be8b4595654a57db663b3d1dfc2
Author: Chuang Wang <nashuiliang@gmail.com>
Date: Tue Dec 27 10:30:36 2022 +0800
tracing/osnoise: Use built-in RCU list checking
list_for_each_entry_rcu() has built-in RCU and lock checking.
Pass cond argument to list_for_each_entry_rcu() to silence false lockdep
warning when CONFIG_PROVE_RCU_LIST is enabled.
Execute as follow:
[tracing]# echo osnoise > current_tracer
[tracing]# echo 1 > tracing_on
[tracing]# echo 0 > tracing_on
The trace_types_lock is held when osnoise_tracer_stop() or
timerlat_tracer_stop() are called in the non-RCU read side section.
So, pass lockdep_is_held(&trace_types_lock) to silence false lockdep
warning.
Link: https://lkml.kernel.org/r/20221227023036.784337-1-nashuiliang@gmail.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: dae181349f1e ("tracing/osnoise: Support a list of trace_array *tr")
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Chuang Wang <nashuiliang@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2174944
commit b5dce2002567a9b1a83ef3e3a8678d8c32be2a78
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Dec 9 23:05:53 2022 +0100
tracing/osnoise: Add preempt and/or irq disabled options
The osnoise workload runs with preemption and IRQs enabled in such
a way as to allow all sorts of noise to disturb osnoise's execution.
hwlat tracer has a similar workload but works with irq disabled,
allowing only NMIs and the hardware to generate noise.
While thinking about adding an options file to hwlat tracer to
allow the system to panic, and other features I was thinking
to add, like having a tracepoint at each noise detection, it
came to my mind that is easier to make osnoise and also do
hardware latency detection than making hwlat "feature compatible"
with osnoise.
Other points are:
- osnoise already has an independent cpu file.
- osnoise has a more intuitive interface, e.g., runtime/period vs.
window/width (and people often need help remembering what it is).
- osnoise: tracepoints
- osnoise stop options
- osnoise options file itself
Moreover, the user-space side (in rtla) is simplified by reusing the
existing osnoise code.
Finally, people have been asking me about using osnoise for hw latency
detection, and I have to explain that it was sufficient but not
necessary. These options make it sufficient and necessary.
Adding a Suggested-by Clark, as he often asked me about this
possibility.
Link: https://lkml.kernel.org/r/d9c6c19135497054986900f94c8e47410b15316a.1670623111.git.bristot@kernel.org
Cc: Suggested-by: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2174944
commit 1603dda47714cebe8a29b2154407da7a929d13f4
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Dec 9 23:05:52 2022 +0100
tracing/osnoise: Add PANIC_ON_STOP option
Often the latency observed in a CPU is not caused by the work being done
in the CPU itself, but by work done on another CPU that causes the
hardware to stall all CPUs. In this case, it is interesting to know
what is happening on ALL CPUs, and the best way to do this is via
crash dump analysis.
Add the PANIC_ON_STOP option to osnoise/timerlat tracers. The default
behavior is having this option off. When enabled by the user, the system
will panic after hitting a stop tracing condition.
This option was motivated by a real scenario that Juri Lelli and I
were debugging.
Link: https://lkml.kernel.org/r/249ce4287c6725543e6db845a6e0df621dc67db5.1670623111.git.bristot@kernel.org
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2174944
commit ec370890f92ba8ad5476a34068655b06ba48def7
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Mon Dec 5 09:27:38 2022 +0100
tracing/osnoise: Make osnoise_options static
Make osnoise_options static, as reported by the kernel test robot.
Link: https://lkml.kernel.org/r/63255826485400d7a2270e9c5e66111079671e7a.1670228712.git.bristot@kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2174944
commit b179d48b6aab21f3999f5006685ea4254c0618a9
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Thu Nov 17 14:46:18 2022 +0100
tracing/osnoise: Add osnoise/options file
Add the tracing/osnoise/options file to control
osnoise/timerlat tracer features. It is a single
file to contain multiple features, similar to
the sched/features file.
Reading the file displays a list of options. Writing
the OPTION_NAME enables it, writing NO_OPTION_NAME disables
it.
The DEAFULTS is a particular option that resets the options
to the default ones.
It uses a bitmask to keep track of the status of the option. When
needed, we can add a list of static keys, but for now
it does not justify the memory increase.
Link: https://lkml.kernel.org/r/f8d34aefdb225d2603fcb4c02a120832a0cd3339.1668692096.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2174944
commit 022632f6c43a86f2135642dccd5686de318e861d
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Thu Nov 17 14:46:17 2022 +0100
tracing/osnoise: Fix duration type
The duration type is a 64 long value, not an int. This was
causing some long noise to report wrong values.
Change the duration to a 64 bits value.
Link: https://lkml.kernel.org/r/a93d8a8378c7973e9c609de05826533c9e977939.1668692096.git.bristot@kernel.org
Cc: stable@vger.kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Fixes: bce29ac9ce ("trace: Add osnoise tracer")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2174944
commit 99ee9317a1305cd5626736785c8cb38b0e47686c
Author: Nico Pache <npache@redhat.com>
Date: Mon Sep 19 08:49:32 2022 -0600
tracing/osnoise: Fix possible recursive locking in stop_per_cpu_kthreads
There is a recursive lock on the cpu_hotplug_lock.
In kernel/trace/trace_osnoise.c:<start/stop>_per_cpu_kthreads:
- start_per_cpu_kthreads calls cpus_read_lock() and if
start_kthreads returns a error it will call stop_per_cpu_kthreads.
- stop_per_cpu_kthreads then calls cpus_read_lock() again causing
deadlock.
Fix this by calling cpus_read_unlock() before calling
stop_per_cpu_kthreads. This behavior can also be seen in commit
f46b16520a ("trace/hwlat: Implement the per-cpu mode").
This error was noticed during the LTP ftrace-stress-test:
WARNING: possible recursive locking detected
--------------------------------------------
sh/275006 is trying to acquire lock:
ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: stop_per_cpu_kthreads
but task is already holding lock:
ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: start_per_cpu_kthreads
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(cpu_hotplug_lock);
lock(cpu_hotplug_lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by sh/275006:
#0: ffff8881023f0470 (sb_writers#24){.+.+}-{0:0}, at: ksys_write
#1: ffffffffb084f430 (trace_types_lock){+.+.}-{3:3}, at: rb_simple_write
#2: ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: start_per_cpu_kthreads
Link: https://lkml.kernel.org/r/20220919144932.3064014-1-npache@redhat.com
Fixes: c8895e271f ("trace/osnoise: Support hotplug operations")
Signed-off-by: Nico Pache <npache@redhat.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2174944
commit 9c556e5a4dd5cfc0939a0575577d0517118f98af
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Tue May 10 11:45:25 2022 +0200
tracing/timerlat: Do not wakeup the thread if the trace stops at the IRQ
There is no need to wakeup the timerlat/ thread if stop tracing is hit
at the timerlat's IRQ handler.
Return before waking up timerlat's thread.
Link: https://lkml.kernel.org/r/b392356c91b56aedd2b289513cc56a84cf87e60d.1652175637.git.bristot@kernel.org
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2174944
commit 4dd2aea24ed7613735664feadc9879d37f718c23
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Tue May 10 11:45:24 2022 +0200
tracing/timerlat: Print stacktrace in the IRQ handler if needed
If print_stack and stop_tracing_us are set, and stop_tracing_us is hit
with latency higher than or equal to print_stack, print the
stack at the IRQ handler as it is useful to define the root cause for
the IRQ latency.
Link: https://lkml.kernel.org/r/fd04530ce98ae9270e41bb124ee5bf67b05ecfed.1652175637.git.bristot@kernel.org
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2174944
commit aa748949b4e665f473bc5abdc5f66029cb5f5522
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Tue May 10 11:45:23 2022 +0200
tracing/timerlat: Notify IRQ new max latency only if stop tracing is set
Currently, the notification of a new max latency is sent from
timerlat's IRQ handler anytime a new max latency is found.
While this behavior is not wrong, the send IPI overhead itself
will increase the thread latency and that is not the desired
effect (tracing overhead).
Moreover, the thread will notify a new max latency again because
the thread latency as it is always higher than the IRQ latency
that woke it up.
The only case in which it is helpful to notify a new max latency
from IRQ is when stop tracing (for the IRQ) is set, as in this
case, the thread will not be dispatched.
Notify a new max latency from the IRQ handler only if stop tracing is
set for the IRQ handler.
Link: https://lkml.kernel.org/r/2c2d9a56c0886c8402ba320de32856cbbb10c2bb.1652175637.git.bristot@kernel.org
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Reported-by: Clark Williams <williams@redhat.com>
Fixes: a955d7eac1 ("trace: Add timerlat tracer")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2078906
Conflicts: Skipped one hunk, in samples, due to not having 3a73333fb370
("tracing: Add TRACE_CUSTOM_EVENT() macro").
commit 9c2136be0878c88c53dea26943ce40bb03ad8d8d
Author: Delyan Kratunov <delyank@fb.com>
Date: Wed May 11 18:28:36 2022 +0000
sched/tracing: Append prev_state to tp args instead
Commit fa2c3254d7cf (sched/tracing: Don't re-read p->state when emitting
sched_switch event, 2022-01-20) added a new prev_state argument to the
sched_switch tracepoint, before the prev task_struct pointer.
This reordering of arguments broke BPF programs that use the raw
tracepoint (e.g. tp_btf programs). The type of the second argument has
changed and existing programs that assume a task_struct* argument
(e.g. for bpf_task_storage access) will now fail to verify.
If we instead append the new argument to the end, all existing programs
would continue to work and can conditionally extract the prev_state
argument on supported kernel versions.
Fixes: fa2c3254d7cf (sched/tracing: Don't re-read p->state when emitting sched_switch event, 2022-01-20)
Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lkml.kernel.org/r/c8a6930dfdd58a4a5755fc01732675472979732b.camel@fb.com
Signed-off-by: Phil Auld <pauld@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit caf4c86bf136845982c5103b2661751b40c474c0
Author: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Date: Mon Mar 7 19:07:40 2022 +0100
tracing/osnoise: Force quiescent states while tracing
At the moment running osnoise on a nohz_full CPU or uncontested FIFO
priority and a PREEMPT_RCU kernel might have the side effect of
extending grace periods too much. This will entice RCU to force a
context switch on the wayward CPU to end the grace period, all while
introducing unwarranted noise into the tracer. This behaviour is
unavoidable as overly extending grace periods might exhaust the system's
memory.
This same exact problem is what extended quiescent states (EQS) were
created for, conversely, rcu_momentary_dyntick_idle() emulates them by
performing a zero duration EQS. So let's make use of it.
In the common case rcu_momentary_dyntick_idle() is fairly inexpensive:
atomically incrementing a local per-CPU counter and doing a store. So it
shouldn't affect osnoise's measurements (which has a 1us granularity),
so we'll call it unanimously.
The uncommon case involve calling rcu_momentary_dyntick_idle() after
having the osnoise process:
- Receive an expedited quiescent state IPI with preemption disabled or
during an RCU critical section. (activates rdp->cpu_no_qs.b.exp
code-path).
- Being preempted within in an RCU critical section and having the
subsequent outermost rcu_read_unlock() called with interrupts
disabled. (t->rcu_read_unlock_special.b.blocked code-path).
Neither of those are possible at the moment, and are unlikely to be in
the future given the osnoise's loop design. On top of this, the noise
generated by the situations described above is unavoidable, and if not
exposed by rcu_momentary_dyntick_idle() will be eventually seen in
subsequent rcu_read_unlock() calls or schedule operations.
Link: https://lkml.kernel.org/r/20220307180740.577607-1-nsaenzju@redhat.com
Cc: stable@vger.kernel.org
Fixes: bce29ac9ce ("trace: Add osnoise tracer")
Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit f0cfe17bcc1dd2f0872966b554a148e888833ee9
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 9 14:13:02 2022 +0100
tracing/osnoise: Do not unregister events twice
Nicolas reported that using:
# trace-cmd record -e all -M 10 -p osnoise --poll
Resulted in the following kernel warning:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1217 at kernel/tracepoint.c:404 tracepoint_probe_unregister+0x280/0x370
[...]
CPU: 0 PID: 1217 Comm: trace-cmd Not tainted 5.17.0-rc6-next-20220307-nico+ #19
RIP: 0010:tracepoint_probe_unregister+0x280/0x370
[...]
CR2: 00007ff919b29497 CR3: 0000000109da4005 CR4: 0000000000170ef0
Call Trace:
<TASK>
osnoise_workload_stop+0x36/0x90
tracing_set_tracer+0x108/0x260
tracing_set_trace_write+0x94/0xd0
? __check_object_size.part.0+0x10a/0x150
? selinux_file_permission+0x104/0x150
vfs_write+0xb5/0x290
ksys_write+0x5f/0xe0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7ff919a18127
[...]
---[ end trace 0000000000000000 ]---
The warning complains about an attempt to unregister an
unregistered tracepoint.
This happens on trace-cmd because it first stops tracing, and
then switches the tracer to nop. Which is equivalent to:
# cd /sys/kernel/tracing/
# echo osnoise > current_tracer
# echo 0 > tracing_on
# echo nop > current_tracer
The osnoise tracer stops the workload when no trace instance
is actually collecting data. This can be caused both by
disabling tracing or disabling the tracer itself.
To avoid unregistering events twice, use the existing
trace_osnoise_callback_enabled variable to check if the events
(and the workload) are actually active before trying to
deactivate them.
Link: https://lore.kernel.org/all/c898d1911f7f9303b7e14726e7cc9678fbfb4a0e.camel@redhat.com/
Link: https://lkml.kernel.org/r/938765e17d5a781c2df429a98f0b2e7cc317b022.1646823913.git.bristot@kernel.org
Cc: stable@vger.kernel.org
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Fixes: 2fac8d6486d5 ("tracing/osnoise: Allow multiple instances of the same tracer")
Reported-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit dd990352f01ee9a6c6eee152e5d11c021caccfe4
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Feb 18 16:17:38 2022 +0100
tracing/osnoise: Make osnoise_main to sleep for microseconds
osnoise's runtime and period are in the microseconds scale, but it is
currently sleeping in the millisecond's scale. This behavior roots in the
usage of hwlat as the skeleton for osnoise.
Make osnoise to sleep in the microseconds scale. Also, move the sleep to
a specialized function.
Link: https://lkml.kernel.org/r/302aa6c7bdf2d131719b22901905e9da122a11b2.1645197336.git.bristot@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit 0878355b51f5f26632e652c848a8e174bb02d22d
Author: Nikita Yushchenko <nikita.yushchenko@virtuozzo.com>
Date: Sun Jan 9 18:34:59 2022 +0300
tracing/osnoise: Properly unhook events if start_per_cpu_kthreads() fails
If start_per_cpu_kthreads() called from osnoise_workload_start() returns
error, event hooks are left in broken state: unhook_irq_events() called
but unhook_thread_events() and unhook_softirq_events() not called, and
trace_osnoise_callback_enabled flag not cleared.
On the next tracer enable, hooks get not installed due to
trace_osnoise_callback_enabled flag.
And on the further tracer disable an attempt to remove non-installed
hooks happened, hitting a WARN_ON_ONCE() in tracepoint_remove_func().
Fix the error path by adding the missing part of cleanup.
While at this, introduce osnoise_unhook_events() to avoid code
duplication between this error path and normal tracer disable.
Link: https://lkml.kernel.org/r/20220109153459.3701773-1-nikita.yushchenko@virtuozzo.com
Cc: stable@vger.kernel.org
Fixes: bce29ac9ce ("trace: Add osnoise tracer")
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Nikita Yushchenko <nikita.yushchenko@virtuozzo.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit d7458bc0d8b409460713228d2ed279addb38947a
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Thu Nov 11 23:07:42 2021 +0100
tracing/osnoise: Make osnoise_instances static
Make the struct list_head osnoise_instances definition static.
Link: https://lore.kernel.org/all/202111120052.ZuikQSJi-lkp@intel.com/
Link: https://lkml.kernel.org/r/d001f0eeac66e2b2eeec7d2a15e9e7abede0453a.1636667971.git.bristot@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Fixes: dae181349f1e ("tracing/osnoise: Support a list of trace_array *tr")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit 01e181c776fddf3a9e7a2ef229cc6e7ddf126fe7
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Sun Oct 31 19:05:04 2021 +0100
tracing/osnoise: Remove PREEMPT_RT ifdefs from inside functions
Remove CONFIG_PREEMPT_RT from inside functions, avoiding
compilation problems in the future.
Link: https://lkml.kernel.org/r/37ee0881b033cdc513efc84ebea26cf77880c8c2.1635702894.git.bristot@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit b14f4568d391c3b9bda9c078a32977e3f939f020
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Sun Oct 31 19:05:03 2021 +0100
tracing/osnoise: Remove STACKTRACE ifdefs from inside functions
Remove CONFIG_STACKTRACE from inside functions, avoiding
compilation problems in the future.
Link: https://lkml.kernel.org/r/3465cca2f28e1ba602a1fc8bdb28d12950b5226e.1635702894.git.bristot@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit 2fac8d6486d5c34e2ec7028580142b8209da3f92
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Sun Oct 31 19:05:02 2021 +0100
tracing/osnoise: Allow multiple instances of the same tracer
Currently, the user can start only one instance of timerlat/osnoise
tracers and the tracers cannot run in parallel.
As starting point to add more flexibility, let's allow the same tracer to
run on different trace instances. The workload will start when the first
trace_array (instance) is registered and stop when the last instance
is unregistered.
So, while this patch allows the same tracer to run in multiple
instances (e.g., two instances running osnoise), it still does not allow
instances of timerlat and osnoise in parallel (e.g., one timerlat and
osnoise). That is because the osnoise: events have different behavior
depending on which tracer is enabled (osnoise or timerlat). Enabling
the parallel usage of these two tracers is in my TODO list.
Link: https://lkml.kernel.org/r/38c8f14b613492a4f3f938d9d3bf0b063b72f0f0.1635702894.git.bristot@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit ccb6754495ef253af5e1253434f0d21b6225c4ad
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Sun Oct 31 19:05:01 2021 +0100
tracing/osnoise: Remove TIMERLAT ifdefs from inside functions
Remove CONFIG_TIMERLAT_TRACER from inside functions, avoiding
compilation problems in the future.
Link: https://lkml.kernel.org/r/8245abb5a112d249f5da6c1df499244ad9e647bc.1635702894.git.bristot@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit dae181349f1e9d279f171afc708d2824ab35a86f
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Sun Oct 31 19:05:00 2021 +0100
tracing/osnoise: Support a list of trace_array *tr
osnoise/timerlat were built to run a single instance, and for this,
a single variable is enough to store the current struct trace_array
*tr with information about the tracing instance. This is done via
the *osnoise_trace variable. A trace_array represents a trace instance.
In preparation to support multiple instances, replace the
*osnoise_trace variable with an RCU protected list of instances.
The operations that refer to an instance now propagate to all
elements of the list (all instances).
Also, replace the osnoise_busy variable with a check if the list
has elements (busy).
No functional change is expected with this patch, i.e., only one
instance is allowed yet.
Link: https://lkml.kernel.org/r/91d006e889b9a5d1ff258fe6077f021ae3f26372.1635702894.git.bristot@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit 2bd1bdf01fb25906f18cd8ebfac81c2217d1478a
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Sun Oct 31 19:04:59 2021 +0100
tracing/osnoise: Use start/stop_per_cpu_kthreads() on osnoise_cpus_write()
When writing a new CPU mask via osnoise/cpus, if the tracer is running,
the workload is restarted to follow the new cpumask. The restart is
currently done using osnoise_workload_start/stop(), which disables the
workload *and* the instrumentation. However, disabling the
instrumentation is not necessary.
Calling start/stop_per_cpu_kthreads() is enough to apply the new
osnoise/cpus config.
Link: https://lkml.kernel.org/r/ee633e82867c5b88851aa6040522a799c0034486.1635702894.git.bristot@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit 15ca4bdb0327b35e09682a0f7975e21688f54306
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Sun Oct 31 19:04:58 2021 +0100
tracing/osnoise: Split workload start from the tracer start
In preparation from supporting multiple trace instances, create
workload start/stop specific functions.
No functional change.
Link: https://lkml.kernel.org/r/74b090971e9acdd13625be1c28ef3270d2275e77.1635702894.git.bristot@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit c3b6343c0dc4a76f838e25391f6f1cdb25cfbb8c
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Sun Oct 31 19:04:57 2021 +0100
tracing/osnoise: Improve comments about barrier need for NMI callbacks
trace_osnoise_callback_enabled is used by ftrace_nmi_enter/exit()
to know when to call the NMI callback. The barrier is used to
avoid having callbacks enabled before the resetting date during
the start or to touch the values after stopping the tracer.
Link: https://lkml.kernel.org/r/a413b8f14aa9312fbd1ba99f96225a8aed831053.1635702894.git.bristot@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit 66df27f19f7dacae471f7214df5bab93d6f88b5f
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Sun Oct 31 19:04:56 2021 +0100
tracing/osnoise: Do not follow tracing_cpumask
In preparation to support multiple instances, decouple the
osnoise/timelat workload from instance-specific tracing_cpumask.
Different instances can have conflicting cpumasks, making osnoise
workload management needlessly complex. Osnoise already has its
global cpumask.
I also thought about using the first instance mask, but the
"first" instance could be removed before the others.
This also fixes the problem that changing the tracing_mask was not
re-starting the trace.
Link: https://lkml.kernel.org/r/169a71bcc919ce3ab53ae6f9ca5cde57fffaf9c6.1635702894.git.bristot@kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit aeafcb82d99c97ff5c6054a4091eeb12aefca9ab
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Oct 15 17:07:51 2021 +0200
trace/timerlat: Add migrate-disabled field to the timerlat header
Since "54357f0c9149 tracing: Add migrate-disabled counter to tracing
output," the migrate disabled field is also printed in the !PREEMPR_RT
kernel config. While this information was added to the vast majority of
tracers, osnoise and timerlat were not updated (because they are new
tracers).
Fix timerlat header by adding the information about migrate disabled.
Link: https://lkml.kernel.org/r/bc0c234ab49946cdd63effa6584e1d5e8662cb44.1634308385.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: x86@kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Fixes: 54357f0c9149 ("tracing: Add migrate-disabled counter to tracing output.")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2069708
commit e0f3b18be733ac4a3b6deb2ff586bc1936ad0368
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Oct 15 17:07:50 2021 +0200
trace/osnoise: Add migrate-disabled field to the osnoise header
Since "54357f0c9149 tracing: Add migrate-disabled counter to tracing
output," the migrate disabled field is also printed in the !PREEMPR_RT
kernel config. While this information was added to the vast majority of
tracers, osnoise and timerlat were not updated (because they are new
tracers).
Fix osnoise header by adding the information about migrate disabled.
Link: https://lkml.kernel.org/r/9cb3d54e29e0588dbba12e81486bd8a09adcd8ca.1634308385.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: x86@kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Fixes: 54357f0c9149 ("tracing: Add migrate-disabled counter to tracing output.")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Tomas Glozar
Luis Claudio R. Goncalves
John Kacur
Scott Weaver
Chris White
Phil Auld
Jerome Marchand