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Commit eb8417aa authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf/x86/intel: Remove division from the intel_pmu_drain_pebs_nhm() hot path 



Only do the division in case we have to print the result out in a warning.

Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-43nl31erfbajwpfj254f6zji@git.kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7f2ee91f

arch/x86/kernel/cpu/perf_event_intel_ds.c

+5 −5
Original line number Diff line number Diff line
@@ -944,7 +944,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs) 
	struct perf_event *event = NULL;

	void *at, *top;

	u64 status = 0;

	int bit, n;

	int bit;



	if (!x86_pmu.pebs_active)

		return;
@@ -954,16 +954,16 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs) 


	ds->pebs_index = ds->pebs_buffer_base;



	n = (top - at) / x86_pmu.pebs_record_size;

	if (n <= 0)

	if (unlikely(at > top))

		return;



	/*

	 * Should not happen, we program the threshold at 1 and do not

	 * set a reset value.

	 */

	WARN_ONCE(n > x86_pmu.max_pebs_events,

		  "Unexpected number of pebs records %d\n", n);

	WARN_ONCE(top - at > x86_pmu.max_pebs_events * x86_pmu.pebs_record_size,

		  "Unexpected number of pebs records %ld\n",

		  (top - at) / x86_pmu.pebs_record_size);



	for (; at < top; at += x86_pmu.pebs_record_size) {

		struct pebs_record_nhm *p = at;