commit 3d7b8ea7a8a20a45d019382c4dc6ed79e8bb95cf upstream.
The help text in osnoise top and timerlat top had some minor errors
and omissions. The -d option was missing the 's' (second) abbreviation and
the error message for '-d' used '-D'.
Cc: stable@vger.kernel.org
Fixes: 1eceb2fc2c ("rtla/osnoise: Add osnoise top mode")
Fixes: a828cd18bc ("rtla: Add timerlat tool and timelart top mode")
Link: https://lore.kernel.org/20240813155831.384446-1-ezulian@redhat.com
Suggested-by: Tomas Glozar <tglozar@redhat.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Eder Zulian <ezulian@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 90574d2a675947858b47008df8d07f75ea50d0d0 upstream.
If the "tool->data" allocation fails then there is no need to call
osnoise_free_top() and, in fact, doing so will lead to a NULL dereference.
Cc: stable@vger.kernel.org
Cc: John Kacur <jkacur@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Fixes: 1eceb2fc2c ("rtla/osnoise: Add osnoise top mode")
Link: https://lore.kernel.org/f964ed1f-64d2-4fde-ad3e-708331f8f358@stanley.mountain
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a40e5e4dd0207485dee75e2b8e860d5853bcc5f7 upstream.
When copying timerlat auto-analysis from a terminal to some web pages or
chats, the \t are being replaced with a single ' ' or ' ', breaking
the output.
For example:
## CPU 3 hit stop tracing, analyzing it ##
IRQ handler delay: 1.30 us (0.11 %)
IRQ latency: 1.90 us
Timerlat IRQ duration: 3.00 us (0.24 %)
Blocking thread: 1223.16 us (99.00 %)
insync:4048 1223.16 us
IRQ interference 4.93 us (0.40 %)
local_timer:236 4.93 us
------------------------------------------------------------------------
Thread latency: 1235.47 us (100%)
Replace \t with spaces to avoid this problem.
Link: https://lkml.kernel.org/r/ec7ed2b2809c22ab0dfc8eb7c805ab9cddc4254a.1713968967.git.bristot@kernel.org
Cc: stable@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Juri Lelli <juri.lelli@redhat.com>
Fixes: 27e348b221 ("rtla/timerlat: Add auto-analysis core")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5f0769331a965675cdfec97c09f3f6e875d7c246 upstream.
Instead of printing three times the same output, print it only once,
reducing lines and being sure that all no values have the same length.
It also fixes an extra '\n' when running the with kernel threads, like
here:
=============== %< ==============
Timer Latency
0 00:00:01 | IRQ Timer Latency (us) | Thread Timer Latency (us)
CPU COUNT | cur min avg max | cur min avg max
2 #0 | - - - - | 161 161 161 161
3 #0 | - - - - | 161 161 161 161
8 #1 | 54 54 54 54 | - - - -'\n'
---------------|----------------------------------------|---------------------------------------
ALL #1 e0 | 54 54 54 | 161 161 161
=============== %< ==============
This '\n' should have been removed with the user-space support that
added another '\n' if not running with kernel threads.
Link: https://lkml.kernel.org/r/0a4d8085e7cd706733a5dc10a81ca38b82bd4992.1713968967.git.bristot@kernel.org
Cc: stable@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Juri Lelli <juri.lelli@redhat.com>
Fixes: cdca4f4e5e ("rtla/timerlat_top: Add timerlat user-space support")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 01b05fc0e5f3aec443a9a8ffa0022cbca2fd3608 upstream.
On short runs it is possible to get no samples on a cpu, like this:
# rtla timerlat hist -u -T50
Index IRQ-001 Thr-001 Usr-001 IRQ-002 Thr-002 Usr-002
2 1 0 0 0 0 0
33 0 1 0 0 0 0
36 0 0 1 0 0 0
49 0 0 0 1 0 0
52 0 0 0 0 1 0
over: 0 0 0 0 0 0
count: 1 1 1 1 1 0
min: 2 33 36 49 52 18446744073709551615
avg: 2 33 36 49 52 -
max: 2 33 36 49 52 0
rtla timerlat hit stop tracing
IRQ handler delay: (exit from idle) 48.21 us (91.09 %)
IRQ latency: 49.11 us
Timerlat IRQ duration: 2.17 us (4.09 %)
Blocking thread: 1.01 us (1.90 %)
swapper/2:0 1.01 us
------------------------------------------------------------------------
Thread latency: 52.93 us (100%)
Max timerlat IRQ latency from idle: 49.11 us in cpu 2
Note, the value 18446744073709551615 is the same as ~0.
Fix this by reporting no results for the min, avg and max if the count
is 0.
Link: https://lkml.kernel.org/r/20240510190318.44295-1-jkacur@redhat.com
Cc: stable@vger.kernel.org
Fixes: 1eeb6328e8 ("rtla/timerlat: Add timerlat hist mode")
Suggested-by: Daniel Bristot de Oliveria <bristot@kernel.org>
Signed-off-by: John Kacur <jkacur@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit df73757cf8f66fa54c4721c53b0916af3c4d9818 upstream.
Fix the following -Wformat-security compile warnings adding missing
format arguments:
latency-collector.c: In function ‘show_available’:
latency-collector.c:938:17: warning: format not a string literal and
no format arguments [-Wformat-security]
938 | warnx(no_tracer_msg);
| ^~~~~
latency-collector.c:943:17: warning: format not a string literal and
no format arguments [-Wformat-security]
943 | warnx(no_latency_tr_msg);
| ^~~~~
latency-collector.c: In function ‘find_default_tracer’:
latency-collector.c:986:25: warning: format not a string literal and
no format arguments [-Wformat-security]
986 | errx(EXIT_FAILURE, no_tracer_msg);
|
^~~~
latency-collector.c: In function ‘scan_arguments’:
latency-collector.c:1881:33: warning: format not a string literal and
no format arguments [-Wformat-security]
1881 | errx(EXIT_FAILURE, no_tracer_msg);
| ^~~~
Link: https://lore.kernel.org/linux-trace-kernel/20240404011009.32945-1-skhan@linuxfoundation.org
Cc: stable@vger.kernel.org
Fixes: e23db805da ("tracing/tools: Add the latency-collector to tools directory")
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 64dc40f7523369912d7adb22c8cb655f71610505 upstream.
When compiling rtla with clang, I am getting the following warnings:
$ make HOSTCC=clang CC=clang LLVM_IAS=1
[..]
clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions
-fstack-protector-strong -fasynchronous-unwind-tables
-fstack-clash-protection -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
$(pkg-config --cflags libtracefs)
-c -o src/osnoise_hist.o src/osnoise_hist.c
src/osnoise_hist.c:138:6: warning: variable 'bucket' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
138 | if (data->bucket_size)
| ^~~~~~~~~~~~~~~~~
src/osnoise_hist.c:149:6: note: uninitialized use occurs here
149 | if (bucket < entries)
| ^~~~~~
src/osnoise_hist.c:138:2: note: remove the 'if' if its condition is always true
138 | if (data->bucket_size)
| ^~~~~~~~~~~~~~~~~~~~~~
139 | bucket = duration / data->bucket_size;
src/osnoise_hist.c:132:12: note: initialize the variable 'bucket' to silence this warning
132 | int bucket;
| ^
| = 0
1 warning generated.
[...]
clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions
-fstack-protector-strong -fasynchronous-unwind-tables
-fstack-clash-protection -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
$(pkg-config --cflags libtracefs)
-c -o src/timerlat_hist.o src/timerlat_hist.c
src/timerlat_hist.c:181:6: warning: variable 'bucket' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
181 | if (data->bucket_size)
| ^~~~~~~~~~~~~~~~~
src/timerlat_hist.c:204:6: note: uninitialized use occurs here
204 | if (bucket < entries)
| ^~~~~~
src/timerlat_hist.c:181:2: note: remove the 'if' if its condition is always true
181 | if (data->bucket_size)
| ^~~~~~~~~~~~~~~~~~~~~~
182 | bucket = latency / data->bucket_size;
src/timerlat_hist.c:175:12: note: initialize the variable 'bucket' to silence this warning
175 | int bucket;
| ^
| = 0
1 warning generated.
This is a legit warning, but data->bucket_size is always > 0 (see
timerlat_hist_parse_args()), so the if is not necessary.
Remove the unneeded if (data->bucket_size) to avoid the warning.
Link: https://lkml.kernel.org/r/6e1b1665cd99042ae705b3e0fc410858c4c42346.1707217097.git.bristot@kernel.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Donald Zickus <dzickus@redhat.com>
Fixes: 1eeb6328e8 ("rtla/timerlat: Add timerlat hist mode")
Fixes: 829a6c0b56 ("rtla/osnoise: Add the hist mode")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b5f319360371087d52070d8f3fc7789e80ce69a6 upstream.
Fix rtla so that the following commands exit with 0 when help is invoked
rtla osnoise top -h
rtla osnoise hist -h
rtla timerlat top -h
rtla timerlat hist -h
Link: https://lore.kernel.org/linux-trace-devel/20240203001607.69703-1-jkacur@redhat.com
Cc: stable@vger.kernel.org
Fixes: 1eeb6328e8 ("rtla/timerlat: Add timerlat hist mode")
Signed-off-by: John Kacur <jkacur@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 14f08c976ffe0d2117c6199c32663df1cbc45c65 upstream.
Since the sched_priority for SCHED_OTHER is always 0, it makes no
sence to set it.
Setting nice for SCHED_OTHER seems more meaningful.
Link: https://lkml.kernel.org/r/20240207065142.1753909-1-limingming3@lixiang.com
Cc: stable@vger.kernel.org
Fixes: b1696371d8 ("rtla: Helper functions for rtla")
Signed-off-by: limingming3 <limingming3@lixiang.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 696444a544ecd6d62c1edc89516b376cefb28929 ]
Variable found is not being initialized, in the case where the desired
mount is not found the variable contains garbage. Fix this by initializing
it to zero.
Link: https://lore.kernel.org/all/20230727150117.627730-1-colin.i.king@gmail.com/
Fixes: a957cbc025 ("rtla: Add -C cgroup support")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
If no CPU list is passed, timerlat in user-space will dispatch
one thread per sysconf(_SC_NPROCESSORS_CONF). However, not all
CPU might be available, for instance, if HT is disabled.
Currently, rtla timerlat is stopping the session if an user-space
thread cannot set affinity to a CPU, or if a running user-space
thread is killed. However, this is too restrictive.
So, reduce the error to a debug message, and rtla timerlat run as
long as there is at least one user-space thread alive.
Link: https://lore.kernel.org/lkml/59cf2c882900ab7de91c6ee33b382ac7fa6b4ed0.1694781909.git.bristot@kernel.org
Fixes: cdca4f4e5e ("rtla/timerlat_top: Add timerlat user-space support")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
timerlat auto-analysis takes note of all IRQs, before or after the
execution of the timerlat thread.
Because we cannot go backward in the trace (we will fix it when
moving to trace-cmd lib?), timerlat aa take note of the last IRQ
execution in the waiting for the IRQ state, and then print it
if it is executed after the expected timer IRQ starting time.
After the thread sample, the timerlat starts recording the next IRQs as
"previous" irq for the next occurrence.
However, if an IRQ happens after the thread measurement but before the
tracing stops, it is classified as a previous IRQ. That is not
wrong, as it can be "previous" for the subsequent activation. What is
wrong is considering it as a potential source for the last activation.
Ignore the IRQ interference that happens after the IRQ starting time for
now. A future improvement for timerlat can be either keeping a list of
previous IRQ execution or using the trace-cmd library. Still, it requires
further investigation - it is a new feature.
Link: https://lore.kernel.org/lkml/a44a3f5c801dcc697bacf7325b65d4a5b0460537.1691162043.git.bristot@kernel.org
Fixes: 27e348b221 ("rtla/timerlat: Add auto-analysis core")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
When estimating the IRQ timer delay, we are dealing with two different
clock sources: the external clock source that timerlat uses as a reference
and the clock used by the tracer. There are also two moments: the time
reading the clock and the timer in which the event is placed in the
buffer (the trace event timestamp).
If the processor is slow or there is some hardware noise, the difference
between the timestamp and the external clock, read can be longer than the
IRQ handler delay, resulting in a negative time.
If so, set IRQ to start delay as 0. In the end, it is less near-zero and relevant
then the noise.
Link: https://lore.kernel.org/lkml/a066fb667c7136d86dcddb3c7ccd72587db3e7c7.1691162043.git.bristot@kernel.org
Fixes: 27e348b221 ("rtla/timerlat: Add auto-analysis core")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
The thread thread_thread_sum accounts for thread interference
during a single activation. It was not being zeroed, so it was
accumulating thread interference over all activations.
It was not that visible when timerlat was the highest priority.
Link: https://lore.kernel.org/lkml/97bff55b0141f2d01b47d9450a5672fde147b89a.1691162043.git.bristot@kernel.org
Fixes: 27e348b221 ("rtla/timerlat: Add auto-analysis core")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
osnoise runs 100% of time by default. It makes sense because osnoise
is preemptive. hwnoise checks preemption once a second, so it
reduces system progress.
Reduce runtime to 75% to avoid problems by default. I added a Fixes
as it might avoid problems for first time users as it lands on distros.
Link: https://lkml.kernel.org/r/af0b7113ffc00031b9af4bb40ef5889a27dadf8c.1686066600.git.bristot@kernel.org
Cc: William White <chwhite@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Fixes: 1f428356c3 ("rtla: Add hwnoise tool")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Group all start tracing after finishing creating all instances.
The tracing instance starts first for the case of hitting a stop
tracing while enabling other instances. The trace instance is the
one with most valuable information.
Link: https://lkml.kernel.org/r/67da7a703a56f75d7cd46568525145a65501a7e8.1686066600.git.bristot@kernel.org
Cc: William White <chwhite@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Add auto-analysis to timerlat hist, including the --no-aa option to
reduce overhead and --dump-task. --aa-only was not added as it is
already on timerlat top.
Link: https://lkml.kernel.org/r/c2693f47ee83e659a7723fed8035f5d2534f528e.1686066600.git.bristot@kernel.org
Cc: William White <chwhite@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Currently, the auto-analysis is attached to the timerlat top instance.
The idea was to avoid creating another instance just for that, so one
instance could be reused.
The drawback is that, by doing so, the auto-analysis run for the entire
session, consuming CPU time. On my 24 box CPUs for timerlat with a 100
us period consumed 50 % with auto analysis, but only 16 % without.
By creating an instance for auto-analysis, we can keep the processing
stopped until a stop tracing condition is hit. Once it happens,
timerlat auto-analysis can use its own trace instance to parse only
the end of the trace.
By doing so, auto-analysis stop consuming cpu time when it is not
needed.
If the --aa-only is passed, the timerlat top instance is reused for
auto analysis.
Link: https://lkml.kernel.org/r/346b7168c1bae552a415715ec6d23c129a43bdb7.1686066600.git.bristot@kernel.org
Cc: William White <chwhite@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When the user sets -c <cpu-list> try to move rtla out of the <cpu-list>,
even without an -H option. This is useful to avoid having rtla
interfering with the workload.
This works by removing <cpu-list> from rtla's current affinity.
If rtla fails to move itself away it is not that of a problem as this
is an automatic measure.
Link: https://lkml.kernel.org/r/c54304d90c777310fb85a3e658d1449173759aab.1686066600.git.bristot@kernel.org
Cc: William White <chwhite@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Use a cpumask instead of a char *, reducing memory footprint and code.
No functional change, and in preparation for auto house-keeping.
Link: https://lkml.kernel.org/r/54c46293261d13cb1042d0314486539eeb45fe5d.1686066600.git.bristot@kernel.org
Cc: William White <chwhite@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
To avoid having rtla interfering with the measurement threads, add an
option for the user to set the CPUs in which rtla should run. For
instance:
# rtla timerlat top -H 0 -c 1-7
Will place rtla in the CPU 0, while running the measurement threads in
the CPU 1-7.
Link: https://lkml.kernel.org/r/6a6c78a579a96ba8b02ae67ee1e0ba2cb5e03c4a.1686066600.git.bristot@kernel.org
Cc: William White <chwhite@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Suggested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The -C option sets a cgroup to the tracer's threads. If the -C option is
passed without arguments, the tracer's thread will inherit rtla's
cgroup. Otherwise, the threads will be placed on the cgroup passed
to the option.
Link: https://lkml.kernel.org/r/cb051477331d292f17c08bf1d66f0e0384bbe5a5.1686066600.git.bristot@kernel.org
Cc: William White <chwhite@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The "Previous IRQ interference" line is misaligned and without
a \n, breaking the tool's output:
## CPU 12 hit stop tracing, analyzing it ##
Previous IRQ interference: up to 2.22 us IRQ handler delay: 18.06 us (0.00 %)
IRQ latency: 18.52 us
Timerlat IRQ duration: 4.41 us (0.00 %)
Blocking thread: 216.93 us (0.03 %)
Fix the output:
## CPU 7 hit stop tracing, analyzing it ##
Previous IRQ interference: up to 8.93 us
IRQ handler delay: 0.98 us (0.00 %)
IRQ latency: 2.95 us
Timerlat IRQ duration: 11.26 us (0.03 %)
Link: https://lore.kernel.org/linux-trace-devel/8b5819077f15ccf24745c9bf3205451e16ee32d9.1679685525.git.bristot@kernel.org
Fixes: 27e348b221 ("rtla/timerlat: Add auto-analysis core")
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>
Parsing and formating timerlat data might consume a reasonable
amount of CPU time on very large systems, or when timerlat
has a too short period.
Add an option to run timerlat with auto-analysis enabled while
skipping the statistics parsing. In this mode, rtla timerlat
periodically checks if the tracing is on, going to sleep waiting
for the stop tracing condition to stop tracing, or for the
tracing session to finish.
If the stop tracing condition is hit, the tool prints the auto
analysis. Otherwise, the tool prints the max observed latency and
exit. The max observed latency is captured via tracing_max_latency.
Link: https://lore.kernel.org/linux-trace-devel/4dc514d1d5dc353c537a466a9b5af44c266b6da2.1680106912.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>
- Add function names as a way to filter function addresses
- Add sample module to test ftrace ops and dynamic trampolines
- Allow stack traces to be passed from beginning event to end event for
synthetic events. This will allow seeing the stack trace of when a task is
scheduled out and recorded when it gets scheduled back in.
- Add trace event helper __get_buf() to use as a temporary buffer when printing
out trace event output.
- Add kernel command line to create trace instances on boot up.
- Add enabling of events to instances created at boot up.
- Add trace_array_puts() to write into instances.
- Allow boot instances to take a snapshot at the end of boot up.
- Allow live patch modules to include trace events
- Minor fixes and clean ups
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Merge tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt:
- Add function names as a way to filter function addresses
- Add sample module to test ftrace ops and dynamic trampolines
- Allow stack traces to be passed from beginning event to end event for
synthetic events. This will allow seeing the stack trace of when a
task is scheduled out and recorded when it gets scheduled back in.
- Add trace event helper __get_buf() to use as a temporary buffer when
printing out trace event output.
- Add kernel command line to create trace instances on boot up.
- Add enabling of events to instances created at boot up.
- Add trace_array_puts() to write into instances.
- Allow boot instances to take a snapshot at the end of boot up.
- Allow live patch modules to include trace events
- Minor fixes and clean ups
* tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (31 commits)
tracing: Remove unnecessary NULL assignment
tracepoint: Allow livepatch module add trace event
tracing: Always use canonical ftrace path
tracing/histogram: Fix stacktrace histogram Documententation
tracing/histogram: Fix stacktrace key
tracing/histogram: Fix a few problems with stacktrace variable printing
tracing: Add BUILD_BUG() to make sure stacktrace fits in strings
tracing/histogram: Don't use strlen to find length of stacktrace variables
tracing: Allow boot instances to have snapshot buffers
tracing: Add trace_array_puts() to write into instance
tracing: Add enabling of events to boot instances
tracing: Add creation of instances at boot command line
tracing: Fix trace_event_raw_event_synth() if else statement
samples: ftrace: Make some global variables static
ftrace: sample: avoid open-coded 64-bit division
samples: ftrace: Include the nospec-branch.h only for x86
tracing: Acquire buffer from temparary trace sequence
tracing/histogram: Wrap remaining shell snippets in code blocks
tracing/osnoise: No need for schedule_hrtimeout range
bpf/tracing: Use stage6 of tracing to not duplicate macros
...
The canonical location for the tracefs filesystem is at /sys/kernel/tracing.
But, from Documentation/trace/ftrace.rst:
Before 4.1, all ftrace tracing control files were within the debugfs
file system, which is typically located at /sys/kernel/debug/tracing.
For backward compatibility, when mounting the debugfs file system,
the tracefs file system will be automatically mounted at:
/sys/kernel/debug/tracing
Many comments and Kconfig help messages in the tracing code still refer
to this older debugfs path, so let's update them to avoid confusion.
Link: https://lore.kernel.org/linux-trace-kernel/20230215223350.2658616-2-zwisler@google.com
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The hwnoise tool is a special mode for the osnoise top tool.
hwnoise dispatches the osnoise tracer and displays a summary of the noise.
The difference is that it runs the tracer with the OSNOISE_IRQ_DISABLE
option set, thus only allowing only hardware-related noise, resulting in
a simplified output. hwnoise has the same features of osnoise.
An example of the tool's output:
# rtla hwnoise -c 1-11 -T 1 -d 10m -q
Hardware-related Noise
duration: 0 00:10:00 | time is in us
CPU Period Runtime Noise % CPU Aval Max Noise Max Single HW NMI
1 #599 599000000 138 99.99997 3 3 4 74
2 #599 599000000 85 99.99998 3 3 4 75
3 #599 599000000 86 99.99998 4 3 6 75
4 #599 599000000 81 99.99998 4 4 2 75
5 #599 599000000 85 99.99998 2 2 2 75
Link: https://lkml.kernel.org/r/2d6f49a6f3a4f8b51b2c806458b1cff71ad4d014.1675805361.git.bristot@kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Currently, timerlat top displays the timerlat tracer latency results, saving
the intuitive timerlat trace for the developer to analyze.
This patch goes a step forward in the automaton of the scheduling latency
analysis by providing a summary of the root cause of a latency higher than
the passed "stop tracing" parameter if the trace stops.
The output is intuitive enough for non-expert users to have a general idea
of the root cause by looking at each factor's contribution percentage while
keeping the technical detail in the output for more expert users to start
an in dept debug or to correlate a root cause with an existing one.
The terminology is in line with recent industry and academic publications
to facilitate the understanding of both audiences.
Here is one example of tool output:
----------------------------------------- %< -----------------------------------------------------
# taskset -c 0 timerlat -a 40 -c 1-23 -q
Timer Latency
0 00:00:12 | IRQ Timer Latency (us) | Thread Timer Latency (us)
CPU COUNT | cur min avg max | cur min avg max
1 #12322 | 0 0 1 15 | 10 3 9 31
2 #12322 | 3 0 1 12 | 10 3 9 23
3 #12322 | 1 0 1 21 | 8 2 8 34
4 #12322 | 1 0 1 17 | 10 2 11 33
5 #12322 | 0 0 1 12 | 8 3 8 25
6 #12322 | 1 0 1 14 | 16 3 11 35
7 #12322 | 0 0 1 14 | 9 2 8 29
8 #12322 | 1 0 1 22 | 9 3 9 34
9 #12322 | 0 0 1 14 | 8 2 8 24
10 #12322 | 1 0 0 12 | 9 3 8 24
11 #12322 | 0 0 0 15 | 6 2 7 29
12 #12321 | 1 0 0 13 | 5 3 8 23
13 #12319 | 0 0 1 14 | 9 3 9 26
14 #12321 | 1 0 0 13 | 6 2 8 24
15 #12321 | 1 0 1 15 | 12 3 11 27
16 #12318 | 0 0 1 13 | 7 3 10 24
17 #12319 | 0 0 1 13 | 11 3 9 25
18 #12318 | 0 0 0 12 | 8 2 8 20
19 #12319 | 0 0 1 18 | 10 2 9 28
20 #12317 | 0 0 0 20 | 9 3 8 34
21 #12318 | 0 0 0 13 | 8 3 8 28
22 #12319 | 0 0 1 11 | 8 3 10 22
23 #12320 | 28 0 1 28 | 41 3 11 41
rtla timerlat hit stop tracing
## CPU 23 hit stop tracing, analyzing it ##
IRQ handler delay: 27.49 us (65.52 %)
IRQ latency: 28.13 us
Timerlat IRQ duration: 9.59 us (22.85 %)
Blocking thread: 3.79 us (9.03 %)
objtool:49256 3.79 us
Blocking thread stacktrace
-> timerlat_irq
-> __hrtimer_run_queues
-> hrtimer_interrupt
-> __sysvec_apic_timer_interrupt
-> sysvec_apic_timer_interrupt
-> asm_sysvec_apic_timer_interrupt
-> _raw_spin_unlock_irqrestore
-> cgroup_rstat_flush_locked
-> cgroup_rstat_flush_irqsafe
-> mem_cgroup_flush_stats
-> mem_cgroup_wb_stats
-> balance_dirty_pages
-> balance_dirty_pages_ratelimited_flags
-> btrfs_buffered_write
-> btrfs_do_write_iter
-> vfs_write
-> __x64_sys_pwrite64
-> do_syscall_64
-> entry_SYSCALL_64_after_hwframe
------------------------------------------------------------------------
Thread latency: 41.96 us (100%)
The system has exit from idle latency!
Max timerlat IRQ latency from idle: 17.48 us in cpu 4
Saving trace to timerlat_trace.txt
----------------------------------------- >% -----------------------------------------------------
In this case, the major factor was the delay suffered by the IRQ handler
that handles timerlat wakeup: 65.52 %. This can be caused by the
current thread masking interrupts, which can be seen in the blocking
thread stacktrace: the current thread (objtool:49256) disabled interrupts
via raw spin lock operations inside mem cgroup, while doing write
syscall in a btrfs file system.
A simple search for the function name on Google shows that this is
a legit case for disabling the interrupts:
cgroup: Use irqsave in cgroup_rstat_flush_locked()
lore.kernel.org/linux-mm/20220301122143.1521823-2-bigeasy@linutronix.de/
The output also prints other reasons for the latency root cause, such as:
- an IRQ that happened before the IRQ handler that caused delays
- The interference from NMI, IRQ, Softirq, and Threads
The details about how these factors affect the scheduling latency
can be found here:
https://bristot.me/demystifying-the-real-time-linux-latency/
Link: https://lkml.kernel.org/r/3d45f40e630317f51ac6d678e2d96d310e495729.1675179318.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <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>
Currently, timerlat displays a summary of the timerlat tracer results
saving the trace if the system hits a stop condition.
While this represented a huge step forward, the root cause was not
that is accessible to non-expert users.
The auto-analysis fulfill this gap by parsing the trace timerlat runs,
printing an intuitive auto-analysis.
Link: https://lkml.kernel.org/r/1ee073822f6a2cbb33da0c817331d0d4045e837f.1675179318.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <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>
Calculate average value in osnoise-hist summary with two-digit
precision to avoid displaying too optimitic results.
Link: https://lkml.kernel.org/r/20230103103400.275566-3-br015@umbiko.net
Signed-off-by: Andreas Ziegler <br015@umbiko.net>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Sampled durations must be weighted by observed quantity, to arrive at a correct
average duration value.
Perform calculation of total duration by summing (duration * count).
Link: https://lkml.kernel.org/r/20230103103400.275566-2-br015@umbiko.net
Fixes: 829a6c0b56 ("rtla/osnoise: Add the hist mode")
Signed-off-by: Andreas Ziegler <br015@umbiko.net>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
rtla_usage(), osnoise_usage() and timerlat_usage() all exit with an
error status.
However when these are called from help, they should exit with a
non-error status.
Fix this by passing the exit status to the functions.
Note, although we remove the subsequent call to exit after calling
usage, we leave it in at the end of a function to suppress the compiler
warning "control reaches end of a non-void function".
Link: https://lkml.kernel.org/r/20221107144313.22470-1-jkacur@redhat.com
Signed-off-by: John Kacur <jkacur@redhat.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
To allow for distributions and other builders to apply hardening
policy and other customisation, append EXTRA_CFLAGS and EXTRA_LDFLAGS
to the corresponding variables.
Link: https://lore.kernel.org/linux-trace-devel/YtLBshz0nMQ7530H@decadent.org.uk
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>
"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: 0605bf009f ("rtla: Add osnoise tool")
Fixes: a828cd18bc ("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>
RISC-V uses the same (generic) syscall numbers as ARM64.
Link: https://lkml.kernel.org/r/mvma68wl2ul.fsf@suse.de
Signed-off-by: Andreas Schwab <schwab@suse.de>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Avoid double free by making trace_instance_destroy indempotent. When
trace_instance_init fails, it calls trace_instance_destroy, but its only
caller osnoise_destroy_tool calls it again.
Link: https://lkml.kernel.org/r/mvmilnlkyzx.fsf_-_@suse.de
Fixes: 0605bf009f ("rtla: Add osnoise tool")
Signed-off-by: Andreas Schwab <schwab@suse.de>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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: 8619e32825 ("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>
Replace malloc with calloc and add memory allocating check
of mon_cpus before used.
Link: https://lkml.kernel.org/r/20220615073348.6891-1-jianchunfu@cmss.chinamobile.com
Fixes: 7d0dc9576d ("rtla/timerlat: Add --dma-latency option")
Signed-off-by: jianchunfu <jianchunfu@cmss.chinamobile.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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: b1696371d8 ("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>
- 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: 79ce8f43ac ("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>
Eder Zulian