Hi Jon,

Did you have any luck getting to the bottom of this?

It would be good to take your PMU suspend/resume patches once we know that
they will get used.

On Tue, Jun 12, 2012 at 11:41:27PM +0100, Jon Hunter wrote:

On 06/12/2012 04:31 PM, Will Deacon wrote:

quoted

That's understandable -- one of the CPUs is likely more loaded than the
other. However, I'd like to confirm whether or not you see what I see. With
the 4430_init hack on a 4460, if I run:

# taskset 0x2 perf top

then I get no samples. If I do:

# taskset 0x1 perf top

then I *do* get samples and from *both* CPUs. So it smells more like an
issue poking some configuration registers from CPU1 rather than the IRQ
path being broken. As I said before, if I don't do the extra init hack
then I don't get this problem (but event counters don't tick).

In both cases, I see interrupts on both CPUs. However, typically more on
the CPU that perf is running on (which is probably to be expected). And
I confirm that the only change I made was ...

[...]

When you boot the kernel what 4460 rev does it show (very early in the
kernel boot log)? Mine shows ...

[    0.000000] OMAP4460 ES1.1

Snap: [    0.000000] OMAP4460 ES1.1

However, the A9 version has not changed between ES1.0 and ES1.1. Both
should be r2p10.

Yup, that's what /proc/cpuinfo says.

Will