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

[Peter Zijlstra <peterz@infradead.org>]

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.