Commit-ID: 0bac237845e203dd1439cfc571b1baf1b2274b3b Gitweb: http://git.kernel.org/tip/0bac237845e203dd1439cfc571b1baf1b2274b3b Author: Thomas Gleixner <[email protected]> AuthorDate: Tue, 19 May 2015 00:00:55 +0000 Committer: Ingo Molnar <[email protected]> CommitDate: Wed, 27 May 2015 09:17:40 +0200
perf/x86/intel/cqm: Avoid pointless MSR write If the usage counter is non-zero there is no point to update the rmid in the PQR MSR. Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Acked-by: Matt Fleming <[email protected]> Cc: Kanaka Juvva <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Vikas Shivappa <[email protected]> Cc: Will Auld <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/kernel/cpu/perf_event_intel_cqm.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel_cqm.c b/arch/x86/kernel/cpu/perf_event_intel_cqm.c index 63391f8..2ce69c0 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_cqm.c +++ b/arch/x86/kernel/cpu/perf_event_intel_cqm.c @@ -974,10 +974,12 @@ static void intel_cqm_event_start(struct perf_event *event, int mode) event->hw.cqm_state &= ~PERF_HES_STOPPED; - if (state->cnt++) - WARN_ON_ONCE(state->rmid != rmid); - else + if (state->cnt++) { + if (!WARN_ON_ONCE(state->rmid != rmid)) + return; + } else { WARN_ON_ONCE(state->rmid); + } state->rmid = rmid; /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
