Re: PEBS (in perf) stopped working from 3.6 -> 3.7

[David Ahern]

On 1/4/13 6:05 PM, Steinar H. Gunderson wrote:
> On Fri, Jan 04, 2013 at 05:16:27PM -0700, David Ahern wrote:
> > Known problem. Pick one of: update perf to 3.7, add H to the command
> > (-e cycles:ppH) or apply this patch:
> > https://lkml.org/lkml/2012/12/28/384
>
> I spoke too soon. This works for cycles, but not for branch-misses:
>
>    pannekake:~> sudo perf record -e branch-misses:ppH -a
>
>      Error: sys_perf_event_open() syscall returned with 95 (Operation not supported) for event branch-misses:ppH. /bin/dmesg may provide additional information.
>
>    No hardware sampling interrupt available. No APIC? If so then you can boot the kernel with the "lapic" boot parameter to force-enable it.
>
> Why would the two be different?

I will make a guess that is processor dependent. On an E5540 with 
3.4.11-1.fc16.x86_64, 3.6.10-2.fc16.x86_64, and 3.8 I get the same 
failure message.

But on a E5620, it works fine with 3.4 and 3.7 (no intermediate kernels 
on that box).

David
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