Re: [PATCH v11 8/8] perf: ARM DynamIQ Shared Unit PMU support

[Mark Rutland]

On Thu, Feb 22, 2018 at 12:38:39PM -0800, Saravana Kannan wrote:
> On 02/22/2018 03:33 AM, Mark Rutland wrote:
> > On Wed, Feb 21, 2018 at 06:32:46PM -0800, Saravana Kannan wrote:
> > > I'm not exactly sure if we can add entries to perf_type_id. If that's
> > > allowed maybe we need to add something line PERF_TYPE_DSU and use that?
> > > 
> > > Or if that's not allowed then would it be better to offset the DSU PMU
> > > events by some number (say 0x1000) and then delete the event type check or
> > > pass PERF_TYPE_RAW to perf_pmu_register()?
> > 
> > As above, neither of these should be necessary.
> 
> For the userspace interface. How about the kernel interface though?
> perf_event_create_kernel_counter() takes attr.type as an input. But there's
> no way to look up the DSU PMU's "type".

There is no lookup mechanism currently.

I take it you want to use DSU events from a kernel module?

It would be possible to have a simlar name -> type lookup mechanism
kernel-side, if necessary.

Thanks,
Mark.