oprofile and ARM A9 hardware counter

Will Deacon [off-list ref] writes:

Mans,

On Fri, Jan 27, 2012 at 12:56:35PM +0000, M?ns Rullg?rd wrote:

quoted

Will Deacon [off-list ref] writes:

quoted

Did this lead anywhere in the end? It seems as though Ming Lei has a working
setup but Stephane is unable to replicate it, despite applying the necessary
patches and trying an updated bootloader.

With the patches listed above plus the one in [1], I get PMU interrupts.
However, unless I restrict the profiled process to one CPU
(taskset 1 perf record ...), I get a panic in armpmu_event_update() with
the 'event' argument being null when called from armv7pmu_handle_irq().

[1] http://article.gmane.org/gmane.linux.ports.arm.omap/69696

Great, thanks for trying this out. Which version of the kernel were you
using? I fixed a bunch of NULL pointer derefs. during the 3.2 window, but if
you were using an -rc kernel you have have hit one of them.

This was with the Linaro tilt-3.2 kernel from
git://git.linaro.org/landing-teams/working/ti/kernel.git, commit
73e2c294444f209d281f7cd10b52b53b087e74f1.  Maybe one of the many patches
it has on top of 3.2 is to blame.

-- 
M?ns Rullg?rd
mans at mansr.com