rtla: Unify apply_config between top and hist

The functions osnoise_top_apply_config and osnoise_hist_apply_config, as
well as timerlat_top_apply_config and timerlat_hist_apply_config, are
mostly th

rtla: Unify apply_config between top and hist

The functions osnoise_top_apply_config and osnoise_hist_apply_config, as
well as timerlat_top_apply_config and timerlat_hist_apply_config, are
mostly the same.

Move common part from them into separate functions osnoise_apply_config
and timerlat_apply_config.

For rtla-timerlat, also unify params->user_hist and params->user_top
into one field called params->user_data, and move several fields used
only by timerlat-top into the top-only section of struct
timerlat_params.

Cc: Luis Goncalves <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Tomas Glozar <[email protected]>
Reviewed-by: John Kacur <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla: Fix segfault in save_trace_to_file call

Running rtla with exit on threshold, but without saving trace leads to a
segmenetation fault:

$ rtla timerlat hist -T 10
...
Max timerlat IRQ latency f

rtla: Fix segfault in save_trace_to_file call

Running rtla with exit on threshold, but without saving trace leads to a
segmenetation fault:

$ rtla timerlat hist -T 10
...
Max timerlat IRQ latency from idle: 4.29 us in cpu 0
Segmentation fault

This is caused by null pointer deference in the call of
save_trace_to_file, which attempts to dereference an uninitialized
osnoise_tool variable:

save_trace_to_file(record->trace.inst, params->trace_output);
^ this is uninitialized if params->trace_output is
not set

Fix this by not attempting to dereference "record" if it is NULL and
passing NULL instead. As a safety measure, the first field is also
checked for NULL inside save_trace_to_file.

Cc: John Kacur <[email protected]>
Cc: Luis Goncalves <[email protected]>
Cc: Costa Shulyupin <[email protected]>
Link: https://lore.kernel.org/[email protected]
Fixes: dc4d4e7c72d1 ("rtla: Refactor save_trace_to_file")
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla: Refactor save_trace_to_file

The functions osnoise_hist_main(), osnoise_top_main(),
timerlat_hist_main(), and timerlat_top_main() are lengthy and contain
duplicated code.

Refactor by consolida

rtla: Refactor save_trace_to_file

The functions osnoise_hist_main(), osnoise_top_main(),
timerlat_hist_main(), and timerlat_top_main() are lengthy and contain
duplicated code.

Refactor by consolidating the duplicate lines into the
save_trace_to_file() function.

Cc: Daniel Bristot de Oliveira <[email protected]>
Cc: John Kacur <[email protected]>
Cc: "Luis Claudio R. Goncalves" <[email protected]>
Cc: Eder Zulian <[email protected]>
Cc: Dan Carpenter <[email protected]>
Cc: Gabriele Monaco <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Costa Shulyupin <[email protected]>
Reviewed-by: Tomas Glozar <[email protected]>
Tested-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla/timerlat_hist: Use BPF to collect samples

Collect samples using BPF program instead of pulling them from tracefs.

If the osnoise:timerlat_sample tracepoint is unavailable or the BPF
program fa

rtla/timerlat_hist: Use BPF to collect samples

Collect samples using BPF program instead of pulling them from tracefs.

If the osnoise:timerlat_sample tracepoint is unavailable or the BPF
program fails to load for whatever reason, rtla falls back to the old
implementation.

The collection of samples using the BPF program is fully self-contained
and requires no activity of the userspace part of rtla during the
measurement. Thus, instead of waking up every second to collect samples,
rtla simply sleeps until woken up by a signal or threshold overflow.

Cc: John Kacur <[email protected]>
Cc: Luis Goncalves <[email protected]>
Cc: Gabriele Monaco <[email protected]>
Cc: Clark Williams <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla/timerlat: Unify params struct

Instead of having separate structs timerlat_top_params and
timerlat_hist_params, use one struct timerlat_params for both.

This allows code using the structs to be

rtla/timerlat: Unify params struct

Instead of having separate structs timerlat_top_params and
timerlat_hist_params, use one struct timerlat_params for both.

This allows code using the structs to be shared between timerlat-top and
timerlat-hist.

Cc: John Kacur <[email protected]>
Cc: Luis Goncalves <[email protected]>
Cc: Gabriele Monaco <[email protected]>
Cc: Clark Williams <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla: Report missed event count

Print how many events were missed by trace buffer overflow in the main
instance at the end of the run (for hist) or during the run (for top).

Cc: John Kacur <jkacur@

rtla: Report missed event count

Print how many events were missed by trace buffer overflow in the main
instance at the end of the run (for hist) or during the run (for top).

Cc: John Kacur <[email protected]>
Cc: Luis Goncalves <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Tomas Glozar <[email protected]>
Tested-by: Gabriele Monaco <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

tools/rtla: Add osnoise_trace_is_off()

All of the users of trace_is_off() passes in &record->trace as the second
parameter, where record is a pointer to a struct osnoise_tool. This record
could be N

tools/rtla: Add osnoise_trace_is_off()

All of the users of trace_is_off() passes in &record->trace as the second
parameter, where record is a pointer to a struct osnoise_tool. This record
could be NULL and there is a hidden dependency that the trace field is the
first field to allow &record->trace to work with a NULL record pointer.

In order to make this code a bit more robust, as record shouldn't be
dereferenced if it is NULL, even if the code does work, create a new
function called osnoise_trace_is_off() that takes the pointer to a
struct osnoise_tool as its second parameter. This way it can properly test
if it is NULL before it dereferences it.

The old function trace_is_off() is removed and the function
osnoise_trace_is_off() is added into osnoise.c which is what the
struct osnoise_tool is associated with.

Cc: John Kacur <[email protected]>
Cc: "Luis Claudio R. Goncalves" <[email protected]>
Cc: Eder Zulian <[email protected]>
Cc: Dan Carpenter <[email protected]>
Cc: Tomas Glozar <[email protected]>
Cc: Gabriele Monaco <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Costa Shulyupin <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla/timerlat_hist: Set OSNOISE_WORKLOAD for kernel threads

When using rtla timerlat with userspace threads (-u or -U), rtla
disables the OSNOISE_WORKLOAD option in
/sys/kernel/tracing/osnoise/optio

rtla/timerlat_hist: Set OSNOISE_WORKLOAD for kernel threads

When using rtla timerlat with userspace threads (-u or -U), rtla
disables the OSNOISE_WORKLOAD option in
/sys/kernel/tracing/osnoise/options. This option is not re-enabled in a
subsequent run with kernel-space threads, leading to rtla collecting no
results if the previous run exited abnormally:

$ rtla timerlat hist -u
^\Quit (core dumped)
$ rtla timerlat hist -k -d 1s
Index
over:
count:
min:
avg:
max:
ALL: IRQ Thr Usr
count: 0 0 0
min: - - -
avg: - - -
max: - - -

The issue persists until OSNOISE_WORKLOAD is set manually by running:
$ echo OSNOISE_WORKLOAD > /sys/kernel/tracing/osnoise/options

Set OSNOISE_WORKLOAD when running rtla with kernel-space threads if
available to fix the issue.

Cc: [email protected]
Cc: John Kacur <[email protected]>
Cc: Luis Goncalves <[email protected]>
Link: https://lore.kernel.org/[email protected]
Fixes: ed774f7481fa ("rtla/timerlat_hist: Add timerlat user-space support")
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla/timerlat_hist: Abort event processing on second signal

If either SIGINT is received twice, or after a SIGALRM (that is, after
timerlat was supposed to stop), abort processing events currently l

rtla/timerlat_hist: Abort event processing on second signal

If either SIGINT is received twice, or after a SIGALRM (that is, after
timerlat was supposed to stop), abort processing events currently left
in the tracefs buffer and exit immediately.

This allows the user to exit rtla without waiting for processing all
events, should that take longer than wanted, at the cost of not
processing all samples.

Cc: John Kacur <[email protected]>
Cc: Luis Goncalves <[email protected]>
Cc: Gabriele Monaco <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla/timerlat_hist: Stop timerlat tracer on signal

Currently, when either SIGINT from the user or SIGALRM from the duration
timer is caught by rtla-timerlat, stop_tracing is set to break out of
the

rtla/timerlat_hist: Stop timerlat tracer on signal

Currently, when either SIGINT from the user or SIGALRM from the duration
timer is caught by rtla-timerlat, stop_tracing is set to break out of
the main loop. This is not sufficient for cases where the timerlat
tracer is producing more data than rtla can consume, since in that case,
rtla is looping indefinitely inside tracefs_iterate_raw_events, never
reaches the check of stop_tracing and hangs.

In addition to setting stop_tracing, also stop the timerlat tracer on
received signal (SIGINT or SIGALRM). This will stop new samples so that
the existing samples may be processed and tracefs_iterate_raw_events
eventually exits.

Cc: [email protected]
Cc: John Kacur <[email protected]>
Cc: Luis Goncalves <[email protected]>
Cc: Gabriele Monaco <[email protected]>
Link: https://lore.kernel.org/[email protected]
Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode")
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla/timerlat: Fix histogram ALL for zero samples

rtla timerlat hist currently computers the minimum, maximum and average
latency even in cases when there are zero samples. This leads to
nonsensical

rtla/timerlat: Fix histogram ALL for zero samples

rtla timerlat hist currently computers the minimum, maximum and average
latency even in cases when there are zero samples. This leads to
nonsensical values being calculated for maximum and minimum, and to
divide by zero for average.

A similar bug is fixed by 01b05fc0e5f3 ("rtla/timerlat: Fix histogram
report when a cpu count is 0") but the bug still remains for printing
the sum over all CPUs in timerlat_print_stats_all.

The issue can be reproduced with this command:

$ rtla timerlat hist -U -d 1s
Index
over:
count:
min:
avg:
max:
Floating point exception (core dumped)

(There are always no samples with -U unless the user workload is
created.)

Fix the bug by omitting max/min/avg when sample count is zero,
displaying a dash instead, just like we already do for the individual
CPUs. The logic is moved into a new function called
format_summary_value, which is used for both the individual CPUs
and for the overall summary.

Cc: [email protected]
Link: https://lore.kernel.org/[email protected]
Fixes: 1462501c7a8 ("rtla/timerlat: Add a summary for hist mode")
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla/timerlat: Do not set params->user_workload with -U

Since commit fb9e90a67ee9 ("rtla/timerlat: Make user-space threads
the default"), rtla-timerlat has been defaulting to
params->user_workload i

rtla/timerlat: Do not set params->user_workload with -U

Since commit fb9e90a67ee9 ("rtla/timerlat: Make user-space threads
the default"), rtla-timerlat has been defaulting to
params->user_workload if neither that or params->kernel_workload is set.
This has unintentionally made -U, which sets only params->user_hist/top
but not params->user_workload, to behave like -u unless -k is set,
preventing the user from running a custom workload.

Example:
$ rtla timerlat hist -U -c 0 &
[1] 7413
$ python sample/timerlat_load.py 0
Error opening timerlat fd, did you run timerlat -U?
$ ps | grep timerlatu
7415 pts/4 00:00:00 timerlatu/0

Fix the issue by checking for params->user_top/hist instead of
params->user_workload when setting default thread mode.

Link: https://lore.kernel.org/[email protected]
Fixes: fb9e90a67ee9 ("rtla/timerlat: Make user-space threads the default")
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla/timerlat: Add --deepest-idle-state for hist

Support limiting deepest idle state also for timerlat-hist.

Link: https://lore.kernel.org/[email protected]
Signed-off-by:

rtla/timerlat: Add --deepest-idle-state for hist

Support limiting deepest idle state also for timerlat-hist.

Link: https://lore.kernel.org/[email protected]
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla/timerlat: Make timerlat_hist_cpu->*_count unsigned long long

Do the same fix as in previous commit also for timerlat-hist.

Link: https://lore.kernel.org/20241011121015.2868751-2-tglozar@redhat

rtla/timerlat: Make timerlat_hist_cpu->*_count unsigned long long

Do the same fix as in previous commit also for timerlat-hist.

Link: https://lore.kernel.org/[email protected]
Reported-by: Attila Fazekas <[email protected]>
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla: Fix consistency in getopt_long for timerlat_hist

Commit e9a4062e1527 ("rtla: Add --trace-buffer-size option") adds a new
long option to rtla utilities, but among all affected files,
timerlat_h

rtla: Fix consistency in getopt_long for timerlat_hist

Commit e9a4062e1527 ("rtla: Add --trace-buffer-size option") adds a new
long option to rtla utilities, but among all affected files,
timerlat_hist misses a trailing `:` in the corresponding short option
inside the getopt string (e.g. `\3:`). This patch propagates the `:`.

Although this change is not functionally required, it improves
consistency and slightly reduces the likelihood a future change would
introduce a problem.

Cc: John Kacur <[email protected]>
Cc: Luis Goncalves <[email protected]>
Cc: Tomas Glozar <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Gabriele Monaco <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla: Fix -t\--trace[=file]

The -t option has an optional argument.
The usual case is for a short option to be specified without an '='
and for the long version to be specified with an '='

Various

rtla: Fix -t\--trace[=file]

The -t option has an optional argument.
The usual case is for a short option to be specified without an '='
and for the long version to be specified with an '='

Various forms of this do not work as expected.
For example:
rtla timerlat hist -T50 -tfile.txt
will result in a truncated file name of "ile.txt"

Another example is that the long form without the '=' will result in the
default file name instead of the requested file name.

This patch properly parses the optional argument with and without '='
and with and without spaces for the short form.

This patch was also tested using -t and --trace without providing a file
name both as the last requested option and with a following long and
short option.

For example:

rtla timerlat hist -T50 -t -u
rtla timerlat hist -T50 --trace -u

This fix is applied to both timerlat top and hist
and to osnoise top and hist.

Here is the full testing for rtla timerlat hist.
Before applying the patch

rtla timerlat hist -T50 -t=file.txt
Works as expected, "file.txt"

rtla timerlat hist -T50 -tfile.txt
Truncated file name "ile.txt"

rtla timerlat hist -T50 -t file.txt
Default file name instead of file.txt

rtla timerlat hist -T50 --trace=file.txt
Truncated file name "ile.txt"

rtla timerlat hist -T50 --trace file.txt
Default file name "timerlat_trace.txt" instead of "file.txt"

After applying the patch:

rtla timerlat hist -T50 -t=file.txt
Works as expected, "file.txt"

rtla timerlat hist -T50 -tfile.txt
Works as expected, "file.txt"

rtla timerlat hist -T50 -t file.txt
Works as expected, "file.txt"

rtla timerlat hist -T50 --trace=file.txt
Works as expected, "file.txt"

rtla timerlat hist -T50 --trace file.txt
Works as expected, "file.txt"

In addition the following tests were performed to make sure that
the default file name worked as expected including with trailing
options.

rtla timerlat hist -T50 -t
Works as expected "timerlat_trace.txt"

rtla timerlat hist -T50 --trace
Works as expected "timerlat_trace.txt"

rtla timerlat hist -T50 -t -u
Works as expected "timerlat_trace.txt"

rtla timerlat hist -T50 --trace -u
Works as expected "timerlat_trace.txt"

Link: https://lkml.kernel.org/r/[email protected]

Cc: Daniel Bristot de Oliveria <[email protected]>
Signed-off-by: John Kacur <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>

show more ...

rtla/timerlat: Fix histogram report when a cpu count is 0

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

rtla/timerlat: Fix histogram report when a cpu count is 0

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/[email protected]

Cc: [email protected]
Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode")
Suggested-by: Daniel Bristot de Oliveria <[email protected]>
Signed-off-by: John Kacur <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>

show more ...

rtla: Add --trace-buffer-size option

Add the option allow the users to set a different buffer size for the
trace. For example, in large systems, the user might be interested on
reducing the trace bu

rtla: Add --trace-buffer-size option

Add the option allow the users to set a different buffer size for the
trace. For example, in large systems, the user might be interested on
reducing the trace buffer to avoid large tracing files.

The buffer size is specified in kB, and it is only affecting
the tracing instance.

The function trace_set_buffer_size() appears on libtracefs v1.6,
so increase the minimum required version on Makefile.config.

Link: https://lkml.kernel.org/r/e7c9ca5b3865f28e131a49ec3b984fadf2d056c6.1715860611.git.bristot@kernel.org

Cc: Jonathan Corbet <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: John Kacur <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>

show more ...

rtla/timerlat: Make user-space threads the default

After ther -u addition, most of the known users are setting it. And
it makes sense, as it adds more information, and inherits the default
setup for

rtla/timerlat: Make user-space threads the default

After ther -u addition, most of the known users are setting it. And
it makes sense, as it adds more information, and inherits the default
setup for the threads - e.g., cgroups configs.

Thus, if the user-space interface is available, enable -u. Otherwise,
use the in-kernel thread.

Add the -k option to allow the user to request kernel-threads.

Link: https://lkml.kernel.org/r/9241d3089de4091b124f780ed832a0e6646cadaa.1713968967.git.bristot@kernel.org

Cc: Jonathan Corbet <[email protected]>
Cc: Juri Lelli <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>

show more ...

rtla: Add the --warm-up option

On many cases, the results right after the startup are different
from the rest of the execution, biasing the results. For example,
on osnoise, the scheduler might take

rtla: Add the --warm-up option

On many cases, the results right after the startup are different
from the rest of the execution, biasing the results. For example,
on osnoise, the scheduler might take some time to adapt to the new
busy-loop workload.

Add the --warm-up <seconds> option, adding a warm-up phase (in
seconds) where the workload is set, but the results are discarded.

Link: https://lkml.kernel.org/r/e682d5ce5af90f123bd13220f63d5c3d118a92be.1713968967.git.bristot@kernel.org

Cc: Jonathan Corbet <[email protected]>
Cc: Juri Lelli <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>

show more ...

rtla/timerlat: Add a summary for hist mode

Like on rtla timerlat top, add an overall summary at the bottom
of timerlat hist. For instance:

# timerlat hist -c 0-1 -d 10s -E 20
# RTLA timerlat hi

rtla/timerlat: Add a summary for hist mode

Like on rtla timerlat top, add an overall summary at the bottom
of timerlat hist. For instance:

# timerlat hist -c 0-1 -d 10s -E 20
# RTLA timerlat histogram
# Time unit is microseconds (us)
# Duration: 0 00:00:10
Index IRQ-000 Thr-000 IRQ-001 Thr-001
6 1 0 0 0
7 1 0 0 0
8 1 0 1 0
9 7 0 0 0
10 16 0 0 0
11 1 0 3 0
15 0 0 3 0
16 0 0 12 0
17 0 0 28 0
18 0 2 26 0
19 1 1 80 1
over: 9973 9998 9848 10000
count: 10001 10001 10001 10001
min: 6 18 8 19
avg: 185 204 95 113
max: 428 450 341 371
ALL: IRQ Thr
count: 20002 20002
min: 6 18
avg: 140 159
max: 428 450

Link: https://lkml.kernel.org/r/a6bc06c798f72127edc57d1f99da8d57e1187cee.1713968967.git.bristot@kernel.org

Cc: Jonathan Corbet <[email protected]>
Suggested-by: Juri Lelli <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>

show more ...

tools/rtla: Add -U/--user-load option to timerlat

The timerlat tracer provides an interface for any application to wait
for the timerlat's periodic wakeup. Currently, rtla timerlat uses it
to dispat

tools/rtla: Add -U/--user-load option to timerlat

The timerlat tracer provides an interface for any application to wait
for the timerlat's periodic wakeup. Currently, rtla timerlat uses it
to dispatch its user-space workload (-u option).

But as the tracer interface is generic, rtla timerlat can also be used
to monitor any workload that uses it. For example, a user might
place their own workload to wait on the tracer interface, and
monitor the results with rtla timerlat.

Add the -U option to rtla timerlat top and hist. With this option, rtla
timerlat will not dispatch its workload but only setting up the
system, waiting for a user to dispatch its workload.

The sample code in this patch is an example of python application
that loops in the timerlat tracer fd.

To use it, dispatch:

# rtla timerlat -U

In a terminal, then run the python program on another terminal,
specifying the CPU to run it. For example, setting on CPU 1:

#./timerlat_load.py 1

Then rtla timerlat will start printing the statistics of the
./timerlat_load.py app.

An interesting point is that the "Ret user Timer Latency" value
is the overall response time of the load. The sample load does
a memory copy to exemplify that.

The stop tracing options on rtla timerlat works in this setup
as well, including auto analysis.

Link: https://lkml.kernel.org/r/36e6bcf18fe15c7601048fd4c65aeb193c502cc8.1707229706.git.bristot@kernel.org

Cc: Jonathan Corbet <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>

show more ...

tools/rtla: Exit with EXIT_SUCCESS when help is invoked

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 t

tools/rtla: Exit with EXIT_SUCCESS when help is invoked

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/[email protected]

Cc: [email protected]
Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode")
Signed-off-by: John Kacur <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>

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tools/rtla: Fix uninitialized bucket/data->bucket_size warning

When compiling rtla with clang, I am getting the following warnings:

$ make HOSTCC=clang CC=clang LLVM_IAS=1

[..]
clang -O -g -DVERSI

tools/rtla: Fix uninitialized bucket/data->bucket_size warning

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: [email protected]
Cc: Masami Hiramatsu <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Bill Wendling <[email protected]>
Cc: Justin Stitt <[email protected]>
Cc: Donald Zickus <[email protected]>
Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode")
Fixes: 829a6c0b5698 ("rtla/osnoise: Add the hist mode")
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>

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rtla/timerlat_hist: Add timerlat user-space support

Add the support for running timerlat threads in user-space. In this
mode, enabled with -u/--user-threads, timerlat dispatches user-space
processes

rtla/timerlat_hist: Add timerlat user-space support

Add the support for running timerlat threads in user-space. In this
mode, enabled with -u/--user-threads, timerlat dispatches user-space
processes that will loop in the timerlat_fd, measuring the overhead
for going to user-space and then returning to the kernel - in addition
to the existing measurements.

Here is one example of the tool's output with -u enabled:

$ sudo timerlat hist -u -c 1-3 -d 600
# RTLA timerlat histogram
# Time unit is microseconds (us)
# Duration: 0 00:10:01
Index IRQ-001 Thr-001 Usr-001 IRQ-002 Thr-002 Usr-002 IRQ-003 Thr-003 Usr-003
0 477555 0 0 425287 0 0 474357 0 0
1 122385 7998 0 174616 1921 0 125412 3138 0
2 47 587376 492150 89 594717 447830 147 593463 454872
3 11 2549 101930 7 2682 145580 64 2530 138680
4 3 1954 2833 1 463 4917 11 548 4656
5 0 60 1037 0 138 1117 6 179 1130
6 0 26 1837 0 38 277 1 76 339
7 0 15 143 0 28 147 2 37 156
8 0 10 23 0 11 75 0 12 80
9 0 7 17 0 0 26 0 11 42
10 0 2 11 0 0 18 0 2 20
11 0 0 7 0 1 8 0 2 12
12 0 0 6 0 1 4 0 2 8
13 0 1 3 0 0 0 0 0 1
14 0 1 0 0 0 1 0 0 2
15 0 1 0 0 0 0 0 0 2
16 0 1 2 0 0 0 0 0 0
17 0 0 1 0 0 0 0 0 0
19 0 0 1 0 0 0 0 0 0
over: 0 0 0 0 0 0 0 0 0
count: 600001 600001 600001 600000 600000 600000 600000 600000 600000
min: 0 1 2 0 1 2 0 1 2
avg: 0 1 2 0 2 2 0 2 2
max: 4 16 19 4 12 14 7 12 15

The tuning setup like -p or -C work for the user-space threads as well.

Link: https://lkml.kernel.org/r/b6a042d55003c4a67ff7dce28d96044b7044f00d.1686066600.git.bristot@kernel.org

Cc: William White <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Tested-by: Juri Lelli <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

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