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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 <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
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 <mingo@kernel.org>
This commit is contained in:
Alexander Shishkin 2016-04-28 18:35:46 +03:00 committed by Ingo Molnar
parent 5101ef20f0
commit ccbebba4c6
3 changed files with 8 additions and 0 deletions
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6
arch/x86/events/core.c
View File

@ -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);
}

1
arch/x86/events/intel/core.c
View File

@ -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;

1
arch/x86/events/perf_event.h
View File

@ -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