From ccbebba4c6bfda8e3ef9e431ce2c3d91c5fc5a63 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Thu, 28 Apr 2016 18:35:46 +0300 Subject: [PATCH] perf/x86/intel/pt: Bypass PT vs. LBR exclusivity if the core supports it Not all cores prevent using Intel PT and LBRs simultaneously, although most of them still do as of today. This patch adds an opt-in flag for such cores to disable mutual exclusivity between PT and LBR; also flip it on for Goldmont. Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mathieu Poirier Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: vince@deater.net Link: http://lkml.kernel.org/r/1461857746-31346-4-git-send-email-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/events/core.c | 6 ++++++ arch/x86/events/intel/core.c | 1 + arch/x86/events/perf_event.h | 1 + 3 files changed, 8 insertions(+) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 41d93d0e972b..5e5e76a52f58 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -360,6 +360,9 @@ int x86_add_exclusive(unsigned int what) { int i; + if (x86_pmu.lbr_pt_coexist) + return 0; + if (!atomic_inc_not_zero(&x86_pmu.lbr_exclusive[what])) { mutex_lock(&pmc_reserve_mutex); for (i = 0; i < ARRAY_SIZE(x86_pmu.lbr_exclusive); i++) { @@ -380,6 +383,9 @@ int x86_add_exclusive(unsigned int what) void x86_del_exclusive(unsigned int what) { + if (x86_pmu.lbr_pt_coexist) + return; + atomic_dec(&x86_pmu.lbr_exclusive[what]); atomic_dec(&active_events); } diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 90ba3ae3074e..cd319400dc10 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3609,6 +3609,7 @@ __init int intel_pmu_init(void) */ x86_pmu.pebs_aliases = NULL; x86_pmu.pebs_prec_dist = true; + x86_pmu.lbr_pt_coexist = true; x86_pmu.flags |= PMU_FL_HAS_RSP_1; pr_cont("Goldmont events, "); break; diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index 7d62a02f49a4..8bd764df815d 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -601,6 +601,7 @@ struct x86_pmu { u64 lbr_sel_mask; /* LBR_SELECT valid bits */ const int *lbr_sel_map; /* lbr_select mappings */ bool lbr_double_abort; /* duplicated lbr aborts */ + bool lbr_pt_coexist; /* LBR may coexist with PT */ /* * Intel PT/LBR/BTS are exclusive -- GitLab