Re: perf top for arm64?

[Zenghui Yu]

Hi John,

On 2019/12/11 1:08, Jiri Olsa wrote:
> On Tue, Dec 10, 2019 at 04:52:52PM +0000, John Garry wrote:
> > On 10/12/2019 16:36, Jiri Olsa wrote:
> > > On Tue, Dec 10, 2019 at 04:13:49PM +0000, John Garry wrote:
> > > > Hi all,
> > > >
> > > > I find to my surprise that "perf top" does not work for arm64:
> > > >
> > > > root@ubuntu:/home/john/linux# tools/perf/perf top
> > > > Couldn't read the cpuid for this machine: No such file or directory
> >
> > Hi Jirka,
> >
> > > there was recent change that check on cpuid and quits:
> > >     608127f73779 perf top: Initialize perf_env->cpuid, needed by the per arch annotation init routine
> >
> > ok, this is new code. I obviously didn't check the git history...
> >
> > But, apart from this, there are many other places where get_cpuid() is
> > called. I wonder what else we're missing out on, and whether we should still
> > add it.
>
> right, I was just wondering how come vendor events are working for you,
> but realized we have get_cpuid_str being called in there ;-)
>
> I think we should add it as you have it prepared already,
> could you post it with bigger changelog that would explain
> where it's being used for arm?

I've also seen the similar problem when I was looking to add support
for 'perf kvm stat' on arm64 [1] (which though got stuck due to some
other reasons for a very long time :(

It would be great if your patch can address this issue!


[1] https://lore.kernel.org/patchwork/patch/1087531/


Thanks,
Zenghui