Re: [PATCH 04/29] x86/perfcounters: rework pmc_amd_save_disable_all() and pmc_amd_restore_all()

Paul Mackerras
2009-04-29T12:39:15Z

Ingo Molnar wrote:

> Could we remove the disable-all facility altogether and make the
> core code NMI-safe? The current approach wont scale on CPUs that
> dont have global-disable features.
>
> disable-all was arguably a hack i introduced and which spread too
> far. Can you see a conceptual need for it?

If you're talking about hw_perf_save_disable / hw_perf_restore, please
don't get rid of those. I use them to batch up counter enable/disable
operations so I only have to compute the PMU config once for each
batch rather than every time an individual counter is enabled or
disabled.

Paul.