Thread (19 messages) 19 messages, 6 authors, 2012-05-15

oprofile and ARM A9 hardware counter

From: Jon Hunter <hidden>
Date: 2012-05-11 13:47:17
Also in: linux-omap

Possibly related (same subject, not in this thread)

Hi Will

On 05/11/2012 07:25 AM, Will Deacon wrote:
On Thu, May 10, 2012 at 07:55:01PM +0100, Jon Hunter wrote:
quoted
Hi Will,
Hi Jon,
quoted
For my testing I have just been reading the PM_EMU_PWRSTST register which shows the power state of the EMU power domain. It should read 3 when the power domain is ON and 0 when it is off. I did something like the following (dumping all EMU clock and power domain registers).
I figured I may as well take perf for a spin and see how I got on. The good
news is that the hwmod bits all seem to work as before and the correct IRQs
are requested:

root at florentine-pogen:~# cat /proc/interrupts
           CPU0       CPU1
 29:      44527      17916       GIC  twd
 33:          0          0       GIC  arm-pmu
 34:          0          0       GIC  arm-pmu

But, unfortunately, as you can see from the above, I just can't persuade them
to fire. The PMU counters do tick, but they happily increment through zero
without us realising. I retested with my perf/omap4 branch to make sure my
board is ok, and the irqs do fire there.

Any ideas?
Do you disable OMAP2/3 support in the kernel config, so that CPU_HAS_PMU
is enabled?

Cheers
Jon
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