Re: Announcement: Release Candidate 1 for OProfile 1.0.0

On Thu, Aug 28, 2014 at 07:24:07PM +0100, William Cohen wrote:
> On 08/28/2014 02:07 PM, Will Deacon wrote:
> > Thanks for giving this a whirl. Which was the A9 SoC you used? The PMU
> > interrupts are often not described properly on those, so it could simply be
> > that perf hasn't initialised.
> > 
> The perf utils seem to work on the machine:
> 
> $ perf record ls
> ...
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.011 MB perf.data (~502 samples) ]

Can you take a look at /proc/interrupts after this run, and see if any of
them fired? Also, what does perf report show?

> $ perf stat ls
> ...
> 
>  Performance counter stats for 'ls':
> 
>           6.077000      task-clock (msec)         #    0.401 CPUs utilized          
>                 15      context-switches          #    0.002 M/sec                  
>                  0      cpu-migrations            #    0.000 K/sec                  
>                 96      page-faults               #    0.016 M/sec                  
>          6,003,324      cycles                    #    0.988 GHz                    
>          1,085,235      stalled-cycles-frontend   #   18.08% frontend cycles idle   
>          4,600,125      stalled-cycles-backend    #   76.63% backend  cycles idle   
>          2,117,086      instructions              #    0.35  insns per cycle        
>                                                   #    2.17  stalled cycles per insn
>            220,666      branches                  #   36.312 M/sec                  
>             94,593      branch-misses             #   42.87% of all branches        
> 
>        0.015141693 seconds time elapsed
> 
> 
> However, the oprofile commands do not:
> 
> $ operf ls
> perf_event_open failed with Operation not supported
> Caught runtime_error: Internal Error.  Perf event setup failed.
> Error running profiler

Any chance you can dump the perf_event_attr so we can try to establish
why the kernel is throwing this back at us?

Cheers,

Will

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