Re: [PATCH v7 1/5] perf report: properly handle branch count in match_chain

From: Milian Wolff
Date: Thu Oct 19 2017 - 07:42:27 EST


On Donnerstag, 19. Oktober 2017 13:38:32 CEST Milian Wolff wrote:
> Some of the code paths I introduced before returned too early
> without running the code to handle a node's branch count.
> By refactoring match_chain to only have one exit point, this
> can be remedied.

Note: I tested this with some of the code I have available, but I'm unsure I'm
doing it right. On my system, I never get avg_cycles != 0. I tried:

perf record -b --call-graph dwarf <some binary>
perf report --branch-history --no-children --stdio

I see predicted and iter values as before, so I think nothing is breaking. But
I'm somewhat unsure. Can someone paste an example source code and the perf
commands to get some meaningful avg_cycles? Or does this depend on a newer
Intel CPU? I have currently only a Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz
available.

Cheers

--
Milian Wolff | milian.wolff@xxxxxxxx | Senior Software Engineer
KDAB (Deutschland) GmbH&Co KG, a KDAB Group company
Tel: +49-30-521325470
KDAB - The Qt Experts