Re: Announcement: Release Candidate 1 for OProfile 1.0.0

On 08/28/2014 04:16 PM, Arnaldo Carvalho de Melo wrote:
> Em Thu, Aug 28, 2014 at 03:54:58PM -0400, William Cohen escreveu:
>> On 08/28/2014 02:59 PM, Will Deacon wrote:
>>> 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.
>  
>> Hi Will,
>  
>> Yes, there are cases where dtb doesn't descrbibe the performance
>> monitoring hardware/interrupts properly, but in this case a compulab
>> trimslice with nvidia tegra2 process it appears "perf record ls" seems
>> to work correctly and "perf report" provides sane data.
>  
>> Below is before and after of /proc/interrupts of the "perf record".  I
>> suspect that there is some difference in the way that operf and ocount
>> are trying to set up the events when compared to "perf record" and
>> "perf stat.
>  
>> I should use systemtap to look at the various parameters being passed
>> in to set up perf and determine where "perf" and "operf" diverge.
> 
> You can try using perf evlist to see how 'perf record' sets up the event
> attributes:
> 
> [root@zoo ~]# perf record usleep 1
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.012 MB perf.data (~525 samples) ]
> [root@zoo ~]# perf evlist -v
> cycles: sample_freq=4000, size: 96, sample_type: IP|TID|TIME|PERIOD,
> disabled: 1, inherit: 1, mmap: 1, mmap2: 1, comm: 1, comm_exec: 1, freq:
> 1, enable_on_exec: 1, sample_id_all: 1, exclude_guest: 1
> [root@zoo ~]#
> 
> - Arnaldo
> 

oprofile uses raw events to set up the pmu hardware.  Both the cortex a9 and cortex a15 should be using the same basic setup.  A place setup differs is the processor specific code in the kernel.  Also the kernel kernel on the a15 is a locally built stock 3.15.10 kernel, while the cortex a9 machine is running a fedora kernel that may have patches and different config.

I rolled back to the oprofile-0.9.9-2.fc20.armv7hl rpm and operf works.  So it looks like there is some in the oprofile userspace code regression.  Doing git bisect to see where things broke.

-Will


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