[perf] exporting perf_pmu_register?

[perf] exporting perf_pmu_register?

[Vince Weaver]

Hello

I'm attempting to write a perf pmu driver as a kernel module, but
am finding this difficult to do it properly because
   perf_pmu_register
is not exported.

Would a patch similar to
  https://lkml.org/lkml/2010/8/18/64
be accepted that exported this?

I'm trying to write a RAPL/energy pmu module on a Sandybridge-EP machine
but the sysadmin won't install a custom kernel so I'm stuck trying to do 
it entirely via loadable module, and it turns out this doesn't seem to be 
possible at all :(

Vince
vweaver1@eecs.utk.edu

Re: [perf] exporting perf_pmu_register?

[Peter Zijlstra]

On Thu, 2012-03-15 at 17:41 -0400, Vince Weaver wrote:
> Would a patch similar to
>   https://lkml.org/lkml/2010/8/18/64
> be accepted that exported this?
> 
If it comes with a patch that uses the exports, sure.

Re: [perf] exporting perf_pmu_register?

[Vince Weaver]

On Wed, 6 Jun 2012, Peter Zijlstra wrote:

> On Thu, 2012-03-15 at 17:41 -0400, Vince Weaver wrote:
> > Would a patch similar to
> >   https://lkml.org/lkml/2010/8/18/64
> > be accepted that exported this?
> > 
> If it comes with a patch that uses the exports, sure.
> 

while I understand the logic behind that from a kernel-developer 
perspective, it does make things harder in the real world.

In the end PAPI has implemented RAPL support via reading /dev/cpu/*/msr
because it was easier to convince our sysadmin to give us read-only 
permission to /dev/cpu/*/msr than to take our in-production Sandybridge-EP 
system and patch it up to export perf_pmu_register so we could work on a 
proper driver.

Vince