Re: RFE: perf lock contention --bpf on an RT kernel

[Arnaldo Carvalho de Melo]

Em Thu, Aug 17, 2023 at 10:57:25AM -0300, Arnaldo Carvalho de Melo escreveu:
> Hi Namhyung, I noticed this when trying to use the BPF mode of perf lock
> contention on an RT kernel:
> 
> 
> I tried up to now the following patch, it loads, but produces no output
> :-\

To check that a BPF skel based programs works with this kernel I tried:

[root@nine perf-tools-next]# uname -a
Linux nine 5.14.0-284.18.1.rt14.303.el9_2.x86_64 #1 SMP PREEMPT_RT Wed May 31 13:18:55 EDT 2023 x86_64 x86_64 x86_64 GNU/Linux
[root@nine perf-tools-next]# tools/bpf/runqslower/.output/runqslower 50 | head -20
Tracing run queue latency higher than 50 us
TIME     COMM             PID           LAT(us)
11:13:47 ktimers/5        60                 54
11:13:47 irq_work/5       62                124
11:13:47 ktimers/5        60                 53
11:13:47 irq_work/5       62                 88
11:13:47 swapper/0        3942               59
11:13:47 ktimers/4        52                 55
11:13:47 irq_work/4       54                102
11:13:47 swapper/0        3942               51
11:13:47 ktimers/5        60                 54
11:13:47 irq_work/5       62                 93
11:13:47 swapper/0        3942               51
11:13:47 kworker/2:2      38                141
11:13:47 swapper/4        14                 90
11:13:47 swapper/6        642               102
11:13:47 swapper/7        77                 52
11:13:47 ktimers/7        76                103
11:13:47 irq_work/7       78                 92
11:13:47 ktimers/6        68                 83
[root@nine perf-tools-next]#

- Arnaldo