Commit-ID: 425507fa5f321bb5ce1b5eb57a9586e0cf0b9802 Gitweb: http://git.kernel.org/tip/425507fa5f321bb5ce1b5eb57a9586e0cf0b9802 Author: Andi Kleen <ak@xxxxxxxxxxxxxxx> AuthorDate: Sun, 10 May 2015 12:22:46 -0700 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Tue, 4 Aug 2015 10:16:58 +0200 perf/x86/intel/lbr: Optimize v4 LBR unfreezing In Arch perfmon v4 the GLOBAL_STATUS reset automatically unfreezes LBRs. So no need to do it manually in the LBR code. Add a check to skip it. v2: Move test up to beginning of function. Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: eranian@xxxxxxxxxx Link: http://lkml.kernel.org/r/1431285767-27027-9-git-send-email-andi@xxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/kernel/cpu/perf_event_intel_lbr.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c index 2fb5737..769a42f 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c @@ -141,6 +141,13 @@ static void __intel_pmu_lbr_enable(bool pmi) u64 debugctl, lbr_select = 0, orig_debugctl; /* + * No need to unfreeze manually, as v4 can do that as part + * of the GLOBAL_STATUS ack. + */ + if (pmi && x86_pmu.version >= 4) + return; + + /* * No need to reprogram LBR_SELECT in a PMI, as it * did not change. */ -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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