rtla/osnoise: Add osnoise top mode
authorDaniel Bristot de Oliveira <bristot@kernel.org>
Fri, 10 Dec 2021 18:11:23 +0000 (19:11 +0100)
committerSteven Rostedt <rostedt@goodmis.org>
Thu, 13 Jan 2022 22:02:42 +0000 (17:02 -0500)
commit1eceb2fc2ca549a170d7ee7cd1fde2daeda646ac
tree5f702d5d37895cc6fe66245fd4bf52b4a7aefa5c
parent0605bf009f18d558758df9edef59698bf1389b28
rtla/osnoise: Add osnoise top mode

The rtla osnoise tool is an interface for the osnoise tracer. The
osnoise tracer dispatches a kernel thread per-cpu. These threads read
the time in a loop while with preemption, softirqs and IRQs enabled,
thus allowing all the sources of osnoise during its execution. The
osnoise threads take note of the entry and exit point of any source
of interferences, increasing a per-cpu interference counter. The
osnoise tracer also saves an interference counter for each source
of interference.

The rtla osnoise top mode displays information about the periodic
summary from the osnoise tracer.

One example of rtla osnoise top output is:

[root@alien ~]# rtla osnoise top -c 0-3 -d 1m -q -r 900000 -P F:1
                                         Operating System Noise
duration:   0 00:01:00 | time is in us
CPU Period       Runtime        Noise  % CPU Aval   Max Noise   Max Single          HW          NMI          IRQ      Softirq       Thread
  0 #58         52200000         1031    99.99802          91           60           0            0        52285            0          101
  1 #59         53100000            5    99.99999           5            5           0            9        53122            0           18
  2 #59         53100000            7    99.99998           7            7           0            8        53115            0           18
  3 #59         53100000         8274    99.98441         277           23           0            9        53778            0          660

"rtla osnoise top --help" works and provide information about the
available options.

Link: https://lkml.kernel.org/r/0d796993abf587ae5a170bb8415c49368d4999e1.1639158831.git.bristot@kernel.org
Cc: Tao Zhou <tao.zhou@linux.dev>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tools/tracing/rtla/src/osnoise.c
tools/tracing/rtla/src/osnoise.h
tools/tracing/rtla/src/osnoise_top.c [new file with mode: 0644]