linux.git/tools/tracing/rtla/src/timerlat_top.c, branch v6.12

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

2024-10-03T20:43:22+00:00

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: 1eceb2fc2ca54 ("rtla/osnoise: Add osnoise top mode")
Fixes: a828cd18bc4ad ("rtla: Add timerlat tool and timelart top mode")
Link: https://lore.kernel.org/20240813155831.384446-1-ezulian@redhat.com
Suggested-by: Tomas Glozar 
Reviewed-by: Tomas Glozar 
Signed-off-by: Eder Zulian 
Signed-off-by: Steven Rostedt (Google)

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

2024-05-16T14:49:10+00:00

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/20240515183024.59985-1-jkacur@redhat.com

Cc: Daniel Bristot de Oliveria 
Signed-off-by: John Kacur 
Signed-off-by: Daniel Bristot de Oliveira

rtla: Add --trace-buffer-size option

2024-05-16T14:44:34+00:00

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 
Cc: Juri Lelli 
Cc: John Kacur 
Signed-off-by: Daniel Bristot de Oliveira

rtla/timerlat: Make user-space threads the default

2024-05-15T13:13:57+00:00

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 
Cc: Juri Lelli 
Signed-off-by: Daniel Bristot de Oliveira

rtla: Add the --warm-up option

2024-05-15T13:13:57+00:00

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  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 
Cc: Juri Lelli 
Signed-off-by: Daniel Bristot de Oliveira

rtla/timerlat: Add a summary for top mode

2024-05-15T13:13:57+00:00

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 
Suggested-by: Juri Lelli 
Signed-off-by: Daniel Bristot de Oliveira

rtla/timerlat: Use pretty formatting only on interactive tty

2024-05-15T13:13:57+00:00

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 
Cc: Juri Lelli 
Signed-off-by: Daniel Bristot de Oliveira

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

2024-05-15T13:13:56+00:00

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 
Cc: Juri Lelli 
Fixes: cdca4f4e5e8e ("rtla/timerlat_top: Add timerlat user-space support")
Signed-off-by: Daniel Bristot de Oliveira

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

2024-03-20T04:39:06+00:00

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 
Cc: Masami Hiramatsu 
Signed-off-by: Daniel Bristot de Oliveira

tools/rtla: Exit with EXIT_SUCCESS when help is invoked

2024-02-12T09:59:09+00:00

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: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode")
Signed-off-by: John Kacur 
Signed-off-by: Daniel Bristot de Oliveira