Bugzilla: https://bugzilla.redhat.com/2117497
commit dada03db9bb1984826e61cfcf1418ac73848324d
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri May 13 08:45:53 2022 +0200
rtla: Remove procps-ng dependency
Daniel Wagner reported to me that readproc.h got deprecated. Also,
while the procps-ng library was available on Fedora, it was not available
on RHEL, which is a piece of evidence that it was not that used.
rtla uses procps-ng only to find the PID of the tracers' workload.
I used the procps-ng library to avoid reinventing the wheel. But in this
case, reinventing the wheel took me less time than the time we already
took trying to work around problems.
Implement a function that reads /proc/ entries, checking if:
- the entry is a directory
- the directory name is composed only of digits (PID)
- the directory contains the comm file
- the comm file contains a comm that matches the tracers'
workload prefix.
- then return true; otherwise, return false.
And use it instead of procps-ng.
Link: https://lkml.kernel.org/r/e8276e122ee9eb2c5a0ba8e673fb6488b924b825.1652423574.git.bristot@kernel.org
Cc: John Kacur <jkacur@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tao Zhou <tao.zhou@linux.dev>
Fixes: b1696371d865 ("rtla: Helper functions for rtla")
Reported-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
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/2117497
commit 941a53c39a151e9aceef153cdfaed0f166ba01b7
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Apr 29 18:28:13 2022 +0200
rtla: Fix __set_sched_attr error message
rtla's function __set_sched_attr() was borrowed from stalld, but I
forgot to update the error message to something meaningful for rtla.
Update the error message from:
boost_with_deadline failed to boost pid PID: STRERROR
to a proper one:
Failed to set sched attributes to the pid PID: STRERROR
Link: https://lkml.kernel.org/r/a2d19b2c53f6512aefd1ee7f8c1bd19d4fc8b99d.1651247710.git.bristot@kernel.org
Link: https://lore.kernel.org/r/eeded730413e7feaa13f946924bcf2cbf7dd9561.1650617571.git.bristot@kernel.org/
Fixes: b1696371d865 ("rtla: Helper functions for rtla")
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/2117497
commit 22d146f7c1e97f4870e4497c0202939a031f740c
Author: John Kacur <jkacur@redhat.com>
Date: Fri Apr 29 18:28:12 2022 +0200
rtla: Minor grammar fix for rtla README
- Change to "The rtla meta-tool includes"
- Remove an unnecessary "But, "
- Adjust the formatting of the paragraph resulting from the changes.
- Simplify the wording for the libraries and tools.
Link: https://lkml.kernel.org/r/437f0accdde53713ab3cce46f3564be00487e031.1651247710.git.bristot@kernel.org
Link: https://lore.kernel.org/r/20220408161012.10544-1-jkacur@redhat.com/
Cc: Daniel Bristot de Oliveria <bristot@kernel.org>
Fixes: 79ce8f43ac5a ("rtla: Real-Time Linux Analysis tool")
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: John Kacur <jkacur@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/2117497
commit 39c3d84cb5b52792a7323a338334d8d65b2dbe3f
Author: John Kacur <jkacur@redhat.com>
Date: Fri Apr 29 18:28:11 2022 +0200
rtla: Don't overwrite existing directory mode
The mode on /usr/bin is often 555 these days,
but make install on rtla overwrites this with 755
Fix this by preserving the current directory if it exists.
Link: https://lkml.kernel.org/r/8c294a6961080a1970fd8b73f7bcf1e3984579e2.1651247710.git.bristot@kernel.org
Link: https://lore.kernel.org/r/20220402043939.6962-1-jkacur@redhat.com
Cc: Daniel Bristot de Oliveria <bristot@redhat.com>
Fixes: 79ce8f43ac5a ("rtla: Real-Time Linux Analysis tool")
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: John Kacur <jkacur@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/2117497
commit 2a6b52ed72c822b5ee146a6a00ea66614fe02653
Author: Wan Jiabing <wanjiabing@vivo.com>
Date: Fri Apr 29 18:28:10 2022 +0200
rtla: Avoid record NULL pointer dereference
Fix the following null/deref_null.cocci errors:
./tools/tracing/rtla/src/osnoise_hist.c:870:31-36: ERROR: record is NULL but dereferenced.
./tools/tracing/rtla/src/osnoise_top.c:650:31-36: ERROR: record is NULL but dereferenced.
./tools/tracing/rtla/src/timerlat_hist.c:905:31-36: ERROR: record is NULL but dereferenced.
./tools/tracing/rtla/src/timerlat_top.c:700:31-36: ERROR: record is NULL but dereferenced.
"record" is NULL before calling osnoise_init_trace_tool.
Add a tag "out_free" to avoid dereferring a NULL pointer.
Link: https://lkml.kernel.org/r/ae0e4500d383db0884eb2820286afe34ca303778.1651247710.git.bristot@kernel.org
Link: https://lore.kernel.org/r/20220408151406.34823-1-wanjiabing@vivo.com/
Cc: kael_w@yeah.net
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Fixes: 51d64c3a1819 ("rtla: Add -e/--event support")
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Wan Jiabing <wanjiabing@vivo.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/2117497
commit 90f59ee41abf587ad4675a70434136c8707fdf4b
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Feb 18 18:57:09 2022 +0100
rtla/osnoise: Fix error message when failing to enable trace instance
When a trace instance creation fails, tools are printing:
Could not enable -> osnoiser <- tracer for tracing
Print the actual (and correct) name of the tracer it fails to enable.
Link: https://lkml.kernel.org/r/53ef0582605af91eca14b19dba9fc9febb95d4f9.1645206561.git.bristot@kernel.org
Fixes: b1696371d865 ("rtla: Helper functions for rtla")
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 316f710172461c501f9b73f3b2fc7ce8aa5b84a5
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Feb 18 18:57:08 2022 +0100
rtla/osnoise: Free params at the exit
The variable that stores the parsed command line arguments are not
being free()d at the rtla osnoise top exit path.
Free params variable before exiting.
Link: https://lkml.kernel.org/r/0be31d8259c7c53b98a39769d60cfeecd8421785.1645206561.git.bristot@kernel.org
Fixes: 1eceb2fc2ca5 ("rtla/osnoise: Add osnoise top mode")
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit ff5a55dcdb343e3db9b9fb08795b78544b032773
Author: Ben Hutchings <benh@debian.org>
Date: Sat Jul 16 15:47:08 2022 +0200
tools/rtla: Fix command symlinks
"ln -s" stores the next argument directly as the symlink target, so
it needs to be a relative path. In this case, just "rtla".
Link: https://lore.kernel.org/linux-trace-devel/YtLBXMI6Ui4HLIF1@decadent.org.uk
Fixes: 0605bf009f18 ("rtla: Add osnoise tool")
Fixes: a828cd18bc4a ("rtla: Add timerlat tool and timelart top mode")
Signed-off-by: Ben Hutchings <benh@debian.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/2117497
commit c7d8a598c5b1e21a0957f5dec2ef4139d2d1a23a
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Jul 13 23:32:19 2022 +0200
rtla: Fix Makefile when called from -C tools/
Sedat Dilek reported an error on rtla Makefile when running:
$ make -C tools/ clean
[...]
make[2]: Entering directory
'/home/dileks/src/linux-kernel/git/tools/tracing/rtla'
[...]
'/home/dileks/src/linux-kernel/git/Documentation/tools/rtla'
/bin/sh: 1: test: rtla-make[2]:: unexpected operator <------ The problem
rm: cannot remove '/home/dileks/src/linux-kernel/git': Is a directory
make[2]: *** [Makefile:120: clean] Error 1
make[2]: Leaving directory
This occurred because the rtla calls kernel's Makefile to get the
version in silence mode, e.g.,
$ make -sC ../../.. kernelversion
5.19.0-rc4
But the -s is being ignored when rtla's makefile is called indirectly,
so the output looks like this:
$ make -C ../../.. kernelversion
make: Entering directory '/root/linux'
5.19.0-rc4
make: Leaving directory '/root/linux'
Using 'grep -v make' avoids this problem, e.g.,
$ make -C ../../.. kernelversion | grep -v make
5.19.0-rc4
Thus, add | grep -v make.
Link: https://lkml.kernel.org/r/870c02d4d97a921f02a31fa3b229fc549af61a20.1657747763.git.bristot@kernel.org
Fixes: 8619e32825fd ("rtla: Follow kernel version")
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.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/2117497
commit 75016ca3acd0de79868ef5b0694195fe05288ade
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:40 2022 +0100
rtla: Tools main loop cleanup
I probably started using "do {} while();", but changed all but osnoise_top
to "while(){};" leaving the ; behind.
Cleanup the main loop code, making all tools use "while() {}"
Changcheng Deng reported this problem, as reported by coccicheck:
Fix the following coccicheck review:
./tools/tracing/rtla/src/timerlat_hist.c: 800: 2-3: Unneeded semicolon
./tools/tracing/rtla/src/osnoise_hist.c: 776: 2-3: Unneeded semicolon
./tools/tracing/rtla/src/timerlat_top.c: 596: 2-3: Unneeded semicolon
Link: https://lkml.kernel.org/r/3c1642110aa87c396f5da4a037dabc72dbb9c601.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Reported-by: Changcheng Deng <deng.changcheng@zte.com.cn>
Reported-by: Zeal Robot <zealci@zte.com.cn>
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/2117497
commit 7d0dc9576dc3817c483b408715e506c3e9f37bed
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:39 2022 +0100
rtla/timerlat: Add --dma-latency option
Add the --dma-latency to set /dev/cpu_dma_latency to the
specified value, this aims to avoid having exit from idle
states latencies that could be influencing the analysis.
Link: https://lkml.kernel.org/r/72ddb0d913459f13217086dadafad88a7c46dd28.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 7d38c35167c58153e8b5bea839616d00e90564b9
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:38 2022 +0100
rtla/osnoise: Fix osnoise hist stop tracing message
rtla osnoise hist is printing the following message when hitting stop
tracing:
printf("rtla timelat hit stop tracing\n");
which is obviosly wrong.
s/timerlat/osnoise/ fixing the printf.
Link: https://lkml.kernel.org/r/2b8f090556fe37b81d183b74ce271421f131c77b.1646247211.git.bristot@kernel.org
Fixes: 829a6c0b5698 ("rtla/osnoise: Add the hist mode")
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 28d2160cb1a18cca87a51345e7df47499447f5a4
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:37 2022 +0100
rtla: Check for trace off also in the trace instance
With the addition of --trigger option, it is also possible to stop
the trace from the -t tracing instance using the traceoff trigger.
Make rtla tools to check if the trace is stopped also in the trace
instance, stopping the execution of the tool.
Link: https://lkml.kernel.org/r/59fc7c6f23dddd5c8b7ef1782cf3da51ea2ce0f5.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 761916fd02c2525139aca957b8a53fda1d8b3616
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:36 2022 +0100
rtla/trace: Save event histogram output to a file
The hist: trigger generates a histogram in the file sys/event/hist.
If the hist: trigger is used, automatically save the histogram output of
the event sys:event in the sys_event_hist.txt file.
Link: https://lkml.kernel.org/r/b5c906af31d4e022ffe87fb0848fac5c089087c8.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 44f3a37d1d3eb10770c7fec4eb89495d37957a26
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:35 2022 +0100
rtla: Add --filter support
Add --filter option. This option enables a trace event filtering of the
previous -e sys:event argument.
This option is available for all current tools.
Link: https://lkml.kernel.org/r/509d70b6348d3e5bcbf1f07ab725ce08d063149a.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 5487b6ce267bbafd399f3642062d974832d3eddc
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:34 2022 +0100
rtla/trace: Add trace event filter helpers
Add a set of helper functions to allow rtla tools to filter events
in the trace instance.
Link: https://lkml.kernel.org/r/12623b1684684549d53b90f4bf66fae44584fd14.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 1a754893653f73724d007c2cf95cf6c47d5114c4
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:33 2022 +0100
rtla: Add --trigger support
Add --trigger option. This option enables a trace event trigger to the
previous -e sys:event argument, allowing some advanced tracing options.
For instance, in a system with CPUs 2:23 isolated, it is possible to get
a stack trace of thread wakeup targeting those CPUs while running
osnoise with the following command line:
# osnoise top -c 2-23 -a 50 -e sched:sched_wakeup --trigger="stacktrace if target_cpu >= 2"
This option is available for all current tools.
Link: https://lkml.kernel.org/r/07d2983d5f71261d4da89dbaf02efcad100ab8ee.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 336c92b26cf9aee6c5d5907ef49b90d2665e9d70
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:32 2022 +0100
rtla/trace: Add trace event trigger helpers
Add a set of helper functions to allow rtla tools to trigger event
actions in the trace instance.
Link: https://lkml.kernel.org/r/e0d31abe879a78a5600b64f904d0dfa8f76e4fbb.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 51d64c3a181938da8fb56404524e15776e9c6bf8
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:31 2022 +0100
rtla: Add -e/--event support
Add -e/--event option. This option enables an event in the trace (-t)
session. The argument can be a specific event, e.g., -e sched:sched_switch,
or all events of a system group, e.g., -e sched. Multiple -e are allowed.
It is only active when -t or -a are set.
This option is available for all current tools.
Link: https://lkml.kernel.org/r/6a3b753be9b1e811953995f7f21a86918ad13390.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit b5aa0be25c27a7f21d9a28f0e0057915552d3c1b
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:30 2022 +0100
rtla/trace: Add trace events helpers
Add a set of helper functions to allow the rtla tools to enable
additional tracepoints in the trace instance.
Link: https://lkml.kernel.org/r/932398b36c1bbaa22c7810d7a40ca9b8c5595b94.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 173a3b014827955cefdf972ae673d94b60e31cf8
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:29 2022 +0100
rtla/timerlat: Add the automatic trace option
Add the -a/--auto <arg in us> option. This option sets some commonly
used options while debugging the system. It aims to help users produce
reports in the field, reducing the number of arguments passed to the
tool in the first approach to a problem.
It is equivalent to setting osnoise/stop_tracing_total_us and print_stack
with the argument, and saving the trace to timerlat_trace.txt file if the
trace is stopped automatically.
Link: https://lkml.kernel.org/r/92438f7ef132c731f538cebdf77850300afe04a5.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 2b622edd5eb5a12c1203fdb353c2ce0681672571
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:28 2022 +0100
rtla/osnoise: Add the automatic trace option
Add the -a/--auto <arg in us> option. This option sets some commonly
used options while debugging the system. It aims to help users produce
reports in the field, reducing the number of arguments passed to the
tool in the first approach to a problem.
It is equivalent to setting osnoise/stop_tracing_us with the argument,
setting tracing_thresh to 1 us, and saving the trace to osnoise_trace.txt
file if the trace is stopped automatically.
Link: https://lkml.kernel.org/r/ef04c961b227eb93a83cd0b54bfca45e1a381b77.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit d635316ae92291083ae7a36014e29ed7b306cb04
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:27 2022 +0100
rtla/osnoise: Add an option to set the threshold
Add the -T/--threshold option to set the minimum threshold to be
considered a noise to osnoise top and hist commands. Also update
the man pages.
Link: https://lkml.kernel.org/r/031861200ffdb24a1df4aa72c458706889a20d5d.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 61c57d578bd7ca2aff3652ed62d95e3f8fc6d16e
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Wed Mar 2 20:01:26 2022 +0100
rtla/osnoise: Add support to adjust the tracing_thresh
osnoise uses the tracing_thresh parameter to define the delta between
two reads of the time to be considered a noise.
Add support to get and set the tracing_thresh from osnoise tools.
Link: https://lkml.kernel.org/r/715ad2a53fd40e41bab8c3f1214c1a94e12fb595.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit dd48f316a1216fa10f9ba26852457794417d9bc6
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Feb 18 18:57:07 2022 +0100
rtla/hist: Make -E the short version of --entries
Currently, --entries uses -e as the short version in the hist mode of
timerlat and osnoise tools. But as -e is already used to enable events
on trace sessions by other tools, thus let's keep it available for the
same usage for all rtla tools.
Make -E the short version of --entries for hist mode on all tools.
Note: rtla was merged in this merge window, so rtla was not released yet.
Link: https://lkml.kernel.org/r/5dbf0cbe7364d3a05e708926b41a097c59a02b1e.1645206561.git.bristot@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: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 4bbf59a9db44c78dd3e5c72057548f7c1eb8d2ba
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Tue Feb 8 15:36:21 2022 +0100
rtla: Fix segmentation fault when failing to enable -t
rtla osnoise and timerlat are causing a segmentation fault when running
with the --trace option on a kernel that does not support multiple
instances. For example:
[root@f34 rtla]# rtla osnoise top -t
failed to enable the tracer osnoise
Could not enable osnoiser tracer for tracing
Failed to enable the trace instance
Segmentation fault (core dumped)
This error happens because the exit code of the tools is trying
to destroy the trace instance that failed to be created.
Make osnoise_destroy_tool() aware of possible NULL osnoise_tool *,
and do not attempt to destroy it. This also simplifies the exit code.
Link: https://lkml.kernel.org/r/5660a2b6bf66c2655842360f2d7f6b48db5dba23.1644327249.git.bristot@kernel.org
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Fixes: 1eceb2fc2ca5 ("rtla/osnoise: Add osnoise top mode")
Fixes: 829a6c0b5698 ("rtla/osnoise: Add the hist mode")
Fixes: a828cd18bc4a ("rtla: Add timerlat tool and timelart top mode")
Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode")
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/2117497
commit f35491b861290a2c8258b5f70f9bb5d5ed2a1c6f
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Feb 4 17:24:03 2022 +0100
rtla/utils: Fix session duration parsing
Use gmtime to format the duration time. This avoids problems when the
system uses local time different of Pisa's Local Time.
Link: https://lkml.kernel.org/r/a2f0a37bc006c2561bb8ecd871cd70532b4a9f2d.1643990447.git.bristot@kernel.org
Fixes: b1696371d865 ("rtla: Helper functions for rtla")
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-kernel@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 (Google) <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit d40d48e1f1f25abe755521e33a67f5d2b8b9443c
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Dec 10 19:11:27 2021 +0100
rtla: Add Documentation
Adds the basis for rtla documentation. This patch also
includes the rtla(1) man page.
As suggested by Jonathan Corbet, we are placing these man
pages at Documentation/tools/rtla, using rst format. It
is not linked to the official documentation, though.
The Makefile is based on bpftool's Documentation one.
Link: https://lkml.kernel.org/r/5f510f3e962fc0cd531c43f5a815544dd720c3f2.1639158831.git.bristot@kernel.org
Cc: Tao Zhou <tao.zhou@linux.dev>
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>
Suggested-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit a828cd18bc4ad72ff6d64c0dd23dc814a6741fed
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Dec 10 19:11:25 2021 +0100
rtla: Add timerlat tool and timelart top mode
The rtla timerlat tool is an interface for the timerlat tracer.
The timerlat tracer dispatches a kernel thread per-cpu. These threads set a
periodic timer to wake themselves up and go back to sleep. After the
wakeup, they collect and generate useful information for the debugging of
operating system timer latency.
The timerlat tracer outputs information in two ways. It periodically
prints the timer latency at the timer IRQ handler and the Thread handler.
It also provides information for each noise via the osnoise tracepoints.
The rtla timerlat top mode displays a summary of the periodic output from
the timerlat tracer.
Here is one example of the rtla timerlat tool output:
---------- %< ----------
[root@alien ~]# rtla timerlat top -c 0-3 -d 1m
Timer Latency
0 00:01:00 | IRQ Timer Latency (us) | Thread Timer Latency (us)
CPU COUNT | cur min avg max | cur min avg max
0 #60001 | 0 0 0 3 | 1 1 1 6
1 #60001 | 0 0 0 3 | 2 1 1 5
2 #60001 | 0 0 1 6 | 1 1 2 7
3 #60001 | 0 0 0 7 | 1 1 1 11
---------- >% ----------
Running:
# rtla timerlat --help
# rtla timerlat top --help
provides information about the available options.
Link: https://lkml.kernel.org/r/e95032e20c2b88c962195bf7693bb53c9ebcced8.1639158831.git.bristot@kernel.org
Cc: Tao Zhou <tao.zhou@linux.dev>
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 <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 1eceb2fc2ca549a170d7ee7cd1fde2daeda646ac
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Dec 10 19:11:23 2021 +0100
rtla/osnoise: Add osnoise top mode
The rtla osnoise tool is an interface for the osnoise tracer. The
osnoise tracer dispatches a kernel thread per-cpu. These threads read
the time in a loop while with preemption, softirqs and IRQs enabled,
thus allowing all the sources of osnoise during its execution. The
osnoise threads take note of the entry and exit point of any source
of interferences, increasing a per-cpu interference counter. The
osnoise tracer also saves an interference counter for each source
of interference.
The rtla osnoise top mode displays information about the periodic
summary from the osnoise tracer.
One example of rtla osnoise top output is:
[root@alien ~]# rtla osnoise top -c 0-3 -d 1m -q -r 900000 -P F:1
Operating System Noise
duration: 0 00:01:00 | time is in us
CPU Period Runtime Noise % CPU Aval Max Noise Max Single HW NMI IRQ Softirq Thread
0 #58 52200000 1031 99.99802 91 60 0 0 52285 0 101
1 #59 53100000 5 99.99999 5 5 0 9 53122 0 18
2 #59 53100000 7 99.99998 7 7 0 8 53115 0 18
3 #59 53100000 8274 99.98441 277 23 0 9 53778 0 660
"rtla osnoise top --help" works and provide information about the
available options.
Link: https://lkml.kernel.org/r/0d796993abf587ae5a170bb8415c49368d4999e1.1639158831.git.bristot@kernel.org
Cc: Tao Zhou <tao.zhou@linux.dev>
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 <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 0605bf009f18d558758df9edef59698bf1389b28
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Dec 10 19:11:22 2021 +0100
rtla: Add osnoise tool
The osnoise tool is the interface for the osnoise tracer. The osnoise
tool will have multiple "modes" with different outputs. At this point,
no mode is included.
The osnoise.c includes the osnoise_context abstraction. It serves to
read-save-change-restore the default values from tracing/osnoise/
directory. When the context is deleted, the default values are restored.
It also includes some other helper functions for managing osnoise
tracer sessions.
With these bits and pieces in place, we can start adding some
functionality to rtla.
Link: https://lkml.kernel.org/r/2d44c21ff561f503b4c7b1813892761818118460.1639158831.git.bristot@kernel.org
Cc: Tao Zhou <tao.zhou@linux.dev>
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 <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit b1696371d865fa28bd20adb13d1820ef031f2ee2
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Dec 10 19:11:21 2021 +0100
rtla: Helper functions for rtla
This is a set of utils and tracer helper functions. They are used by
rtla mostly to parse config, display data and some trace operations that
are not part of libtracefs (because they are only useful it for this
case).
Link: https://lkml.kernel.org/r/a94c128aba9e6e66d502b7094f2e8c7ac95b12e5.1639158831.git.bristot@kernel.org
Cc: Tao Zhou <tao.zhou@linux.dev>
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 <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2117497
commit 79ce8f43ac5ac16d6d63729e858da42b0460d87b
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date: Fri Dec 10 19:11:20 2021 +0100
rtla: Real-Time Linux Analysis tool
The rtla is a meta-tool that includes a set of commands that aims
to analyze the real-time properties of Linux. But instead of testing
Linux as a black box, rtla leverages kernel tracing capabilities to
provide precise information about the properties and root causes of
unexpected results.
rtla --help works and provide information about the available options.
This is just the "main" and the Makefile, no function yet.
Link: https://lkml.kernel.org/r/bf9118ed43a09e6c054c9a491cbe7411ad1acd89.1639158831.git.bristot@kernel.org
Cc: Tao Zhou <tao.zhou@linux.dev>
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 <rostedt@goodmis.org>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
There is a spelling mistake in the -g help option, I believe
it should be "graph". There is also a spelling mistake in a
warning message. Fix both mistakes.
Link: https://lkml.kernel.org/r/20210225165248.22050-2-Viktor.Rosendahl@bmw.de
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Viktor Rosendahl <Viktor.Rosendahl@bmw.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This is a tool that is intended to work around the fact that the
preemptoff, irqsoff, and preemptirqsoff tracers only work in
overwrite mode. The idea is to act randomly in such a way that we
do not systematically lose any latencies, so that if enough testing
is done, all latencies will be captured. If the same burst of
latencies is repeated, then sooner or later we will have captured all
the latencies.
It also works with the wakeup_dl, wakeup_rt, and wakeup tracers.
However, in that case it is probably not useful to use the random
sleep functionality.
The reason why it may be desirable to catch all latencies with a long
test campaign is that for some organizations, it's necessary to test
the kernel in the field and not practical for developers to work
iteratively with field testers. Because of cost and project schedules
it is not possible to start a new test campaign every time a latency
problem has been fixed.
It uses inotify to detect changes to /sys/kernel/tracing/trace.
When a latency is detected, it will either sleep or print
immediately, depending on a function that act as an unfair coin
toss.
If immediate print is chosen, it means that we open
/sys/kernel/tracing/trace and thereby cause a blackout period
that will hide any subsequent latencies.
If sleep is chosen, it means that we wait before opening
/sys/kernel/tracing/trace, by default for 1000 ms, to see if
there is another latency during this period. If there is, then we will
lose the previous latency. The coin will be tossed again with a
different probability, and we will either print the new latency, or
possibly a subsequent one.
The probability for the unfair coin toss is chosen so that there
is equal probability to obtain any of the latencies in a burst.
However, this assumes that we make an assumption of how many
latencies there can be. By default the program assumes that there
are no more than 2 latencies in a burst, the probability of immediate
printout will be:
1/2 and 1
Thus, the probability of getting each of the two latencies will be 1/2.
If we ever find that there is more than one latency in a series,
meaning that we reach the probability of 1, then the table will be
expanded to:
1/3, 1/2, and 1
Thus, we assume that there are no more than three latencies and each
with a probability of 1/3 of being captured. If the probability of 1
is reached in the new table, that is we see more than two closely
occurring latencies, then the table will again be extended, and so
on.
On my systems, it seems like this scheme works fairly well, as
long as the latencies we trace are long enough, 300 us seems to be
enough. This userspace program receive the inotify event at the end
of a latency, and it has time until the end of the next latency
to react, that is to open /sys/kernel/tracing/trace. Thus,
if we trace latencies that are >300 us, then we have at least 300 us
to react.
The minimum latency will of course not be 300 us on all systems, it
will depend on the hardware, kernel version, workload and
configuration.
Example usage:
In one shell, give the following command:
sudo latency-collector -rvv -t preemptirqsoff -s 2000 -a 3
This will trace latencies > 2000us with the preemptirqsoff tracer,
using random sleep with maximum verbosity, with a probability
table initialized to a size of 3.
In another shell, generate a few bursts of latencies:
root@host:~# modprobe preemptirq_delay_test delay=3000 test_mode=alternate
burst_size=3
root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger
root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger
root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger
root@host:~# echo 1 > /sys/kernel/preemptirq_delay_test/trigger
If all goes well, you should be getting stack traces that shows
all the different latencies, i.e. you should see all the three
functions preemptirqtest_0, preemptirqtest_1, preemptirqtest_2 in the
stack traces.
Link: https://lkml.kernel.org/r/20210212134421.172750-2-Viktor.Rosendahl@bmw.de
Signed-off-by: Viktor Rosendahl <Viktor.Rosendahl@bmw.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Jerome Marchand
Xu Wang
Colin Ian King
Viktor Rosendahl