Re: [PATCH] arm64: add OProfile support

[Will Deacon]

On Mon, Apr 28, 2014 at 03:32:04AM +0100, Ding Tianhong wrote:
> On 2014/4/26 18:22, Ding Tianhong wrote:
> > On 2014/4/26 17:23, Catalin Marinas wrote:
> >> On 26 Apr 2014, at 09:38, Ding Tianhong <dingtianhong@xxxxxxxxxx> wrote:
> >>> Add OProfile support for arm64,  using the perf backend, and failing back
> >>> to generic timer based sampling if PMU interrupt is not supported.
> >>>
> >>> I have test this patch on Cortex-A53 and Cortex-A57 motherboard, the OProfile
> >>> could work well by PMU irq or arch timer irq.
> >>
> >> This came up before a few times and we also had an implementation but
> >> decided not to merge it. We should rather get the user space oprofile to
> >> use the perf kernel API.
> >>
> >> Thatâs an old thread, it may have even made it into mainline oprofile
> >> but I havenât followed the development:
> >>
> >> http://marc.info/?l=oprofile-list&m=133002515616302&w=2
> >>
> >> Catalin
> >>
> 
> Hi Cadtalin:
> 
> Sorry I could not find the implementation that not to merge the orpfile support for aarch64 till now, and
> I still have questions that the existing code only support oprofile by arch timer event, but not
> PMU event, this patch only add HW PMU support for oprofile, it is more accurate and stable, can you
> give me more advise and appreciate for your help.

Just use the operf tool, which is part of the oprofile project. It uses the
perf syscall under the hood and doesn't need any kernel-side additions over
perf.

Will
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