linux-kernel - [PATCH 1/2] perf/x86/intel/bts: Make it an exclusive PMU

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Message-Id: <20160920154811.3255-2-alexander.shishkin@linux.intel.com>
Date:   Tue, 20 Sep 2016 18:48:10 +0300
From:   Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To:     Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:     Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
        vince@...ter.net, eranian@...gle.com,
        Arnaldo Carvalho de Melo <acme@...radead.org>,
        tglx@...utronix.de,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Subject: [PATCH 1/2] perf/x86/intel/bts: Make it an exclusive PMU

Just like intel_pt, intel_bts can only handle one event at a time,
which is the reason we introduced PERF_PMU_CAP_EXCLUSIVE in the first
place. However, at the moment one can have as many intel_bts events
within the same context at the same time as one pleases. Only one of
them, however, will get scheduled and receive the actual trace data.

Fix this by making intel_bts an "exclusive" PMU.

Signed-off-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
---
 arch/x86/events/intel/bts.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c
index bdcd651099..6112c3d538 100644
--- a/arch/x86/events/intel/bts.c
+++ b/arch/x86/events/intel/bts.c
@@ -584,7 +584,8 @@ static __init int bts_init(void)
 	if (!boot_cpu_has(X86_FEATURE_DTES64) || !x86_pmu.bts)
 		return -ENODEV;
 
-	bts_pmu.capabilities	= PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_ITRACE;
+	bts_pmu.capabilities	= PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_ITRACE |
+				  PERF_PMU_CAP_EXCLUSIVE;
 	bts_pmu.task_ctx_nr	= perf_sw_context;
 	bts_pmu.event_init	= bts_event_init;
 	bts_pmu.add		= bts_event_add;
-- 
2.9.3