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_top: 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 fai

rtla/timerlat_top: 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, rtla only pulls the summary from the BPF map and
displays it every second, improving the performance.

In --aa-only mode, the BPF program does not collect any data and only
signalizes the end of tracing to userspace. An optimization that re-used
the main trace instance for auto-analysis in aa-only mode was dropped, as
rtla no longer turns tracing on in the main trace instance, making it
useless for auto-analysis.

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_top: Move divisor to update

Unlike timerlat-hist, timerlat-top applies the output divisor used to
set ns/us mode when printing results instead of applying it when
collecting the sample

rtla/timerlat_top: Move divisor to update

Unlike timerlat-hist, timerlat-top applies the output divisor used to
set ns/us mode when printing results instead of applying it when
collecting the samples.

Move the application of the divisor from timerlat_top_print into
timerlat_top_update to make it consistent with 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/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_top: 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/option

rtla/timerlat_top: 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 top -u
^\Quit (core dumped)
$ rtla timerlat top -k -d 1s
Timer Latency
0 00:00:01 | IRQ Timer Latency (us) | Thread Timer Latency (us)
CPU COUNT | cur min avg max | cur 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: cdca4f4e5e8e ("rtla/timerlat_top: Add timerlat user-space support")
Signed-off-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

show more ...

rtla/timerlat_top: 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 le

rtla/timerlat_top: 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_top: 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 m

rtla/timerlat_top: 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: a828cd18bc4a ("rtla: Add timerlat tool and timelart top 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 top

Add option to limit deepest idle state on CPUs where timerlat is running
for the duration of the workload.

Link: https://lore.kernel.org/202410171409

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

Add option to limit deepest idle state on CPUs where timerlat is running
for the duration of the workload.

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_top_cpu->*_count unsigned long long

Most fields of struct timerlat_top_cpu are unsigned long long, but the
fields {irq,thread,user}_count are int (32-bit signed).

This

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

Most fields of struct timerlat_top_cpu are unsigned long long, but the
fields {irq,thread,user}_count are int (32-bit signed).

This leads to overflow when tracing on a large number of CPUs for a long
enough time:
$ rtla timerlat top -a20 -c 1-127 -d 12h
...
0 12:00:00 | IRQ Timer Latency (us) | Thread Timer Latency (us)
CPU COUNT | cur min avg max | cur min avg max
1 #43200096 | 0 0 1 2 | 3 2 6 12
...
127 #43200096 | 0 0 1 2 | 3 2 5 11
ALL #119144 e4 | 0 5 4 | 2 28 16

The average latency should be 0-1 for IRQ and 5-6 for thread, but is
reported as 5 and 28, about 4 to 5 times more, due to the count
overflowing when summed over all CPUs: 43200096 * 127 = 5486412192,
however, 1191444898 (= 5486412192 mod MAX_INT) is reported instead, as
seen on the last line of the output, and the averages are thus ~4.6
times higher than they should be (5486412192 / 1191444898 = ~4.6).

Fix the issue by changing {irq,thread,user}_count fields to unsigned
long long, similarly to other fields in struct timerlat_top_cpu and to
the count variable in timerlat_top_print_sum.

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: use the definition for stdout fd when calling isatty()

Use the STDOUT_FILENO definition when testing whether the standard
output file descriptor refers to a terminal (for better redability).

rtla: use the definition for stdout fd when calling isatty()

Use the STDOUT_FILENO definition when testing whether the standard
output file descriptor refers to a terminal (for better redability).

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

show more ...

rtla: Fix the help text in osnoise and timerlat top tools

The help text in osnoise top and timerlat top had some minor errors
and omissions. The -d option was missing the 's' (second) abbreviation a

rtla: Fix the help text in osnoise and timerlat top tools

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: [email protected]
Fixes: 1eceb2fc2ca54 ("rtla/osnoise: Add osnoise top mode")
Fixes: a828cd18bc4ad ("rtla: Add timerlat tool and timelart top mode")
Link: https://lore.kernel.org/[email protected]
Suggested-by: Tomas Glozar <[email protected]>
Reviewed-by: Tomas Glozar <[email protected]>
Signed-off-by: Eder Zulian <[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: 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 top mode

While the per-cpu values are the results to take into consideration, the
overall system values are also useful.

Add a summary at the bottom of rtla timerla

rtla/timerlat: Add a summary for top mode

While the per-cpu values are the results to take into consideration, the
overall system values are also useful.

Add a summary at the bottom of rtla timerlat top showing the overall
results. For instance:

Timer Latency
0 00:00:10 | IRQ Timer Latency (us) | Thread Timer Latency (us)
CPU COUNT | cur min avg max | cur min avg max
0 #10003 | 113 19 150 441 | 134 35 170 459
1 #10003 | 63 8 99 462 | 84 15 119 481
2 #10003 | 3 2 89 396 | 21 8 108 414
3 #10002 | 206 11 210 394 | 223 21 228 415
---------------|----------------------------------------|---------------------------------------
ALL #40011 e0 | 2 137 462 | 8 156 481

Link: https://lkml.kernel.org/r/5eb510d6faeb4ce745e09395196752df75a2dd1a.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 ...

rtla/timerlat: Use pretty formatting only on interactive tty

timerlat top does some background/font color formatting. While useful
on terminal, it breaks the output on other formats. For example, wh

rtla/timerlat: Use pretty formatting only on interactive tty

timerlat top does some background/font color formatting. While useful
on terminal, it breaks the output on other formats. For example, when
piping the output for pastebin tools, the format strings are printed
as characters. For instance:

[2;37;40m Timer Latency [0;0;0m
0 00:00:01 | IRQ Timer Latency (us) | Thread Timer Latency (us)
[2;30;47mCPU COUNT | cur min avg max | cur min avg max[0;0;0m
0 #1013 | 1 0 1 54 | 5 2 4 57
1 #1013 | 3 0 1 10 | 6 2 4 15

To avoid this problem, do the formatting only if running on a tty,
and in !quiet mode.

Link: https://lkml.kernel.org/r/8288e1544ceab21557d5dda93a0f00339497c649.1713968967.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: Simplify "no value" printing on top

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 als

rtla/timerlat: Simplify "no value" printing on top

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: [email protected]
Cc: Jonathan Corbet <[email protected]>
Cc: Juri Lelli <[email protected]>
Fixes: cdca4f4e5e8e ("rtla/timerlat_top: Add timerlat user-space support")
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>

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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]>

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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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