RE: [Linux-ia64] [PATCH] Support for alternative kernel profiler

Luck, Tony
2002-01-10T23:26:58Z

We don't currently have any way for different software packages
to share the performance counters, so it's very likely that there
would be interactions with Stephane's PMU code (e.g. I rewrite
cr.pmv to a new vector and re-write all of the pmc[] and pmd[]
registers for my own purposes ... this will upset Stephane's code,
similarly my code does not expect anyone else to touch any PMU
registers, or fiddle with psr.pp/dcr.pp).

It would probably be safest to turn off CONFIG_PERFMON in a kernel
that is going to load an alternate profiler ... my profiler seems
to cope ok provided nobody calls sys_perfmonctl().

-Tony

David Mosberger wrote:
> I'd like Stephane to take a look at this patch and see whether there
> are any potential bad interactions with the PMU code he is working on
> (due to the manipulation of the psr.pp bit). Other than that, the
> patch looks good to me.