Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression

Ingo Molnar
2016-08-15T05:03:07Z

* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> Make sure you actually use "perf record -e cycles:pp" or something
> that uses PEBS to get real profiles using CPU performance counters.

Btw., 'perf record -e cycles:pp' is the default now for modern versions
of perf tooling (on most x86 systems) - if you do 'perf record' it will
just use the most precise profiling mode available on that particular
CPU model.

If unsure you can check the event that was used, via:

triton:~> perf report --stdio 2>&1 | grep '# Samples'
# Samples: 27K of event 'cycles:pp'

Thanks,

Ingo