Re: [tip:perf/core] perf/x86/intel: Clean-up/reduce PEBS code

Andi Kleen
2013-09-14T06:18:24Z

tip-bot for Peter Zijlstra <tipbot@zytor.com> writes:
> +
> + at = (struct pebs_record_nhm *)(unsigned long)ds->pebs_buffer_base;
> + top = (struct pebs_record_nhm *)(unsigned long)ds->pebs_index;
>
> ds->pebs_index = ds->pebs_buffer_base;
>
> + n = (top - at) / x86_pmu.pebs_record_size;

This adds a full slow division to the PEBS hot path.

Does not seem like a improvement to me.

-Andi

--
ak@linux.intel.com -- Speaking for myself only