linux.git/tools/tracing/rtla/src/timerlat_top.c, branch for-next

Merge tag 'trace-tools-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2024-11-22T21:24:22+00:00

Pull tracing tools updates from Steven Rostedt:

 - Add ':' to getopt option 'trace-buffer-size' in timerlat_hist for
   consistency

 - Remove unused sched_getattr define

 - Rename sched_setattr() helper to syscall_sched_setattr() to avoid
   conflicts

 - Update counters to long from int to avoid overflow

 - Add libcpupower dependency detection

 - Add --deepest-idle-state to timerlat to limit deep idle sleeps

 - Other minor clean ups and documentation changes

* tag 'trace-tools-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  verification/dot2: Improve dot parser robustness
  tools/rtla: Improve exception handling in timerlat_load.py
  tools/rtla: Enhance argument parsing in timerlat_load.py
  tools/rtla: Improve code readability in timerlat_load.py
  rtla/timerlat: Do not set params->user_workload with -U
  rtla: Documentation: Mention --deepest-idle-state
  rtla/timerlat: Add --deepest-idle-state for hist
  rtla/timerlat: Add --deepest-idle-state for top
  rtla/utils: Add idle state disabling via libcpupower
  rtla: Add optional dependency on libcpupower
  tools/build: Add libcpupower dependency detection
  rtla/timerlat: Make timerlat_hist_cpu->*_count unsigned long long
  rtla/timerlat: Make timerlat_top_cpu->*_count unsigned long long
  tools/rtla: fix collision with glibc sched_attr/sched_set_attr
  tools/rtla: drop __NR_sched_getattr
  rtla: Fix consistency in getopt_long for timerlat_hist
  rv: Fix a typo
  tools/rv: Correct the grammatical errors in the comments
  tools/rv: Correct the grammatical errors in the comments
  rtla: use the definition for stdout fd when calling isatty()

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

2024-11-19T13:56:59+00:00

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)

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

2024-10-17T21:13:15+00:00

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

Link: https://lore.kernel.org/20241017140914.3200454-5-tglozar@redhat.com
Signed-off-by: Tomas Glozar 
Signed-off-by: Steven Rostedt (Google)

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

2024-10-11T17:09:57+00:00

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/20241011121015.2868751-1-tglozar@redhat.com
Reported-by: Attila Fazekas 
Signed-off-by: Tomas Glozar 
Signed-off-by: Steven Rostedt (Google)

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

2024-10-04T17:42:22+00:00

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/20240813142338.376039-1-ezulian@redhat.com
Signed-off-by: Eder Zulian 
Signed-off-by: Steven Rostedt (Google)

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