Re: [RFC][PATCH 00/11] perf pmu interface -v2

Peter Zijlstra
2010-06-25T14:50:34Z

On Fri, 2010-06-25 at 15:36 +0100, Will Deacon wrote:
> Hello,
>
> On Fri, 2010-06-25 at 12:16 +0100, Peter Zijlstra wrote:
> > I seem to have lost a refresh before sending the emails, please check:
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/linux-2.6-perf.git perf-pmu
> >
> > I pushed out updated patches there.
>
> Ok, I rebuilt my Kernel and perf tools from that tree and tested it on a
> quad-core ARMv7 board.

Ooh, neat toy ;-)

> Per-task counters appear to work (software and
> hardware) but pinned hardware counters always return 0:
>
>
> root@will-lucid-nfs:~# perf stat -a -e cs -e cycles -e instructions -- ls
> linux-2.6 tmp
>
> Performance counter stats for 'ls':
>
> 33 context-switches
> 0 cycles
> 0 instructions # 0.000 IPC
>
> 0.028572009 seconds time elapsed
>
>
> It's odd if only ARM is affected in this way. Do pinned events still work
> for other people?

/me goes build that exact tree on his x86_64.. and gets:

# perf stat -a -e cs -e cycles -e instructions -- ls > /dev/null

Performance counter stats for 'ls':

51 context-switches
24963513 cycles
9225808 instructions # 0.370 IPC

0.002389051 seconds time elapsed

Not exactly sure how I could have messed up the ARM architecture code to
make this happen though... will have a peek.