Re: [RFC PATCH] perf: Add load latency monitoring on Intel Nehalem/Westmere

Peter Zijlstra
2010-12-22T10:45:17Z

On Wed, 2010-12-22 at 11:08 +0100, Stephane Eranian wrote:
> Yes, I think there is more to it than just data source, unfortunately.
> If you want to avoid returning an opaque u64 (PERF_SAMPLE_EXTRA), then
> you need to break it down: PERF_SAMPLE_DATA_SRC, PERF_SAMPLE_XX
> and so on.

I guess we can do things like:

Satisfied by {L1, L2, L3, RAM}x{snoop, local, remote} + unknown, and
encode "Pending core cache HIT" as L2-snoop or something, whatever is
most appropriate.

But does that cover every architecture?

Also, since that doesn't require more that 4 bits to encode, we could
try and categorize what else is around and try and create a well
specified _EXTRA register, I mean, we still got 60bits left after this.