Re: perf_counters: page fault trace record

From: Corey Ashford
Date: Sat Jun 13 2009 - 04:45:13 EST


Paul Mackerras wrote:
Corey Ashford writes:

One of the tools we are working on needs to be able to look not only at counts of page faults, but where they are occurring (ip and faulting page address).

What would you think about adding a new bit to the config record, something like:

Can't you do what you need just using a page fault software counter
with sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR and
sample_period = 1?

I thought about that, but I was under the (incorrect?) impression that on Power, the PERF_SAMPLE_ADDR would be set by the value of the SDAR register, which wouldn't be correct for the case of a page fault.

I need to go look at the kernel code :)

- Corey

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