linux-stable.git/tools/tracing/rtla/src, branch linux-6.11.y

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

2024-12-05T12:53:44+00:00

[ Upstream commit fcbc60d7dc4b125c8de130aa1512e5d20726c06e ]

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/20241021123140.14652-1-tglozar@redhat.com
Fixes: fb9e90a67ee9 ("rtla/timerlat: Make user-space threads the default")
Signed-off-by: Tomas Glozar 
Signed-off-by: Steven Rostedt (Google) 
Signed-off-by: Sasha Levin

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

2024-10-10T10:04:10+00:00

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: 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) 
Signed-off-by: Greg Kroah-Hartman

rtla/osnoise: Prevent NULL dereference in error handling

2024-08-09T17:03:15+00:00

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 
Cc: "Luis Claudio R. Goncalves" 
Cc: Clark Williams 
Fixes: 1eceb2fc2ca5 ("rtla/osnoise: Add osnoise top mode")
Link: https://lore.kernel.org/f964ed1f-64d2-4fde-ad3e-708331f8f358@stanley.mountain
Signed-off-by: Dan Carpenter 
Signed-off-by: Steven Rostedt (Google)

rtla/osnoise: Better report when histogram is empty

2024-06-21T08:19:53+00:00

When osnoise hist does not observe any samples above the threshold,
no entries are recorded and the final report shows empty entries
for the usual statistics (count, min, max, avg):

    [~]# osnoise hist -d 5s -T 500
    # RTLA osnoise histogram
    # Time unit is microseconds (us)
    # Duration:   0 00:00:05
    Index
    over:
    count:
    min:
    avg:
    max:

That could lead users to confusing interpretations of the results.

A simple solution is to report 0 for count and the statistics, making it
clear that no noise (above the defined threshold) was observed:

    [~]# osnoise hist -d 5s -T 500
    # RTLA osnoise histogram
    # Time unit is microseconds (us)
    # Duration:   0 00:00:05
    Index
    over: 0
    count: 0
    min: 0
    avg: 0
    max: 0

Link: https://lkml.kernel.org/r/Zml6JmH5cbS7-HfZ@uudg.org

Cc: Daniel Bristot de Oliveira 
Cc: John Kacur 
Cc: Clark Williams 
Reviewed-by: John Kacur 
Signed-off-by: Luis Claudio R. Goncalves 
Signed-off-by: Daniel Bristot de Oliveira

rtla/osnoise: Use pretty formatting only on interactive tty

2024-06-21T08:17:51+00:00

osnoise top performs background/font color formatting that could make
the text output confusing if not on a terminal. Use the changes from
commit f5c0cdad6684a ("rtla/timerlat: Use pretty formatting only on
interactive tty") as an inspiration to fix this problem.

Apply the formatting only if running on a tty, and not in quiet mode.

Link: https://lkml.kernel.org/r/Zmb-yP_3EDHliI8Z@uudg.org

Suggested-by: Daniel Bristot de Oliveira 
Reviewed-by: John Kacur 
Reviewed-by: Clark Williams 
Signed-off-by: Luis Claudio R. Goncalves 
Signed-off-by: Daniel Bristot de Oliveira

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

2024-05-16T14:45:40+00:00

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: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode")
Suggested-by: 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