oprofile and ARM A9 hardware counter

[Ming Lei]

Hi,

On Tue, Jan 10, 2012 at 6:49 AM, Will Deacon <will.deacon at arm.com> wrote:
> On Mon, Jan 09, 2012 at 04:39:09PM +0000, Maynard Johnson wrote:
>> On 01/08/2012 8:58 PM, Lik Lik wrote:
>> > Hi all,
>
> Hi guys [adding a bunch of people to CC because this issue is really
> annoying me now],
>
>> > I am an oprofile user and I need to profile one of my applications on a TI OMAP4
>> > platform (pandaboard, to be specific). I have ubuntu 11.10 installed. My problem
>> > is that oprofile always use the timer interrupt mode but doesn't recognize the
>> > hardware counters, which I am sure my platform has.
>
> First and foremost, we can't currently generate PMU interrupts on OMAP4 in
> mainline. There are some additional patches required for these to work:
>
> http://marc.info/?l=linux-arm-kernel&m=131946761428296&w=2
>
> However, as Stephane has pointed out here:
>
> http://marc.info/?l=linux-omap&m=132585784125352&w=2
>
> the interrupts still don't seem to work, even with the patches above
> applied.
>
> Ming Lei doesn't seem to be replying to email anymore, so maybe somebody

Sorry, I am on a trip now and no pandboard at my hand, so I may have
time to verify
the latest mainline next week after I return home.

I remembered that last time I verified these patches on 3.2-rc2 and
3.2-rc2 next tree,
and perf did work well on my pandaboard.

Also seems there were reports that omap4 perf may not work on some specific
uboot version even with these patches.

> else on linux-omap could please help us? I'm hoping that we're just missing
> some patches from somewhere, but it would be great if somebody could verify
> this (and indeed, verify that the interrupts we're registering in the thread
> above look sane).
>
>> OProfile userspace support for ARM Cortex-A9 was added by Will Deacon in June
>> 2010.  This support is available in OProfile 0.9.7.  According to Will's
>> posting, the kernel support was due to be added to Ubuntu Maverick, so I would
>> expect your version should support CA9 out of the box.  If not already using
>> oprofile 0.9.7, please upgrade to that version and retry.  If it still doesn't
>> work, please re-post with complete information (kernel version, oprofile command
>> output, and contents of /dev/oprofile/cpu_type).
>
> If with the latest OProfile, `timer mode' is still reported then you should
> check that you have CONFIG_HW_PERF_EVENTS enabled in your kernel. It still
> won't work though, because of the problems I mentioned above.

If debug message from 'dmesg' can be provided, maybe we can find clue
about the problem.

thanks,
--
Ming Lei