Re: perf record and intel_cqm/llc_occupancy

[Omar Awile <omar.awile@cern.ch>]

Hi Andi,

Thanks, I see your point. I’ve seen tried perf stat for these events, which is quite nice. However, we would like to be able to correlate the cache occupancy with the current call stack. I don’t see how this could be done with perf stat. Is there a way to do this?

Alternatively, since perf record already keeps track of the call stack, is it feasible to extend it to allow recording cache occupancy, or is this inherently impossible?

Finally, if none of the two alternatives work, do you have an idea how else this could be achieved?

Thanks!

Omar

PS. sorry for repost...

On 23 June 2016 at 22:53:43, Andi Kleen (andi@firstfloor.org(mailto:andi@firstfloor.org)) wrote:

> Omar Awile writes:
> >
> > Is it possible that for intel_cqm/llc_occupancy interrupts are not
> > supported?5A
>  
> Interrupts wouldn't be meaningful on these counters because they
> don't count continuous events, but just report the current cache
> occupancy. So yes.
>  
> You can use perf stat -I ... instead to get a time series.
>  
> -Andi