On Tue, Aug 6, 2019 at 1:19 PM Harald Geyer [off-list ref] wrote:

Vasily Khoruzhick writes:

quoted

On Tue, Aug 6, 2019 at 7:35 AM Robin Murphy [off-list ref] wrote:

quoted

On 06/08/2019 15:01, Vasily Khoruzhick wrote:

quoted

Looks like PMU in A64 is broken, it generates no interrupts at all and
as result 'perf top' shows no events.

Does something like 'perf stat sleep 1' at least count cycles correctly?
It could well just be that the interrupt numbers are wrong...

Looks like it does, at least result looks plausible:

I'm using perf stat regularly (cache benchmarks) and it works fine.

Unfortunately I wasn't aware that perf stat is a poor test for
the interrupts part of the node, when I added it. So I'm not too
surprised I got it wrong.

However, it would be unfortunate if the node got removed completely,
because perf stat would not work anymore. Maybe we can only remove
the interrupts or just fix them even if the HW doesn't work?

I'm not familiar with PMU driver. Is it possible to get it working
without interrupts?

Harald