Re: perf_counters: page fault trace record

[Corey Ashford <cjashfor@linux.vnet.ibm.com>]

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