Commit-ID: 425507fa5f321bb5ce1b5eb57a9586e0cf0b9802 Gitweb: http://git.kernel.org/tip/425507fa5f321bb5ce1b5eb57a9586e0cf0b9802 Author: Andi Kleen <[email protected]> AuthorDate: Sun, 10 May 2015 12:22:46 -0700 Committer: Ingo Molnar <[email protected]> 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 <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- 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-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/
