linux-kernel - [PATCH 3.18 073/144] perf/x86/intel: Fix bug for "cycles:p" and "cycles:pp" on SLM

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Date:   Thu,  8 Nov 2018 13:50:44 -0800
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Kan Liang <kan.liang@...el.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Ingo Molnar <mingo@...nel.org>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 3.18 073/144] perf/x86/intel: Fix bug for "cycles:p" and "cycles:pp" on SLM

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 33636732dcd7cc738a5913bb730d663c6b03c8fb ]

cycles:p and cycles:pp do not work on SLM since commit:

   86a04461a99f ("perf/x86: Revamp PEBS event selection")

UOPS_RETIRED.ALL is not a PEBS capable event, so it should not be used
to count cycle number.

Actually SLM calls intel_pebs_aliases_core2() which uses INST_RETIRED.ANY_P
to count the number of cycles. It's a PEBS capable event. But inv and
cmask must be set to count cycles.

Considering SLM allows all events as PEBS with no flags, only
INST_RETIRED.ANY_P, inv=1, cmask=16 needs to handled specially.

Signed-off-by: Kan Liang <kan.liang@...el.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: http://lkml.kernel.org/r/1421084541-31639-1-git-send-email-kan.liang@intel.com
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/kernel/cpu/perf_event_intel_ds.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 46211bcc813e..423cbd9bea3e 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -568,8 +568,8 @@ struct event_constraint intel_atom_pebs_event_constraints[] = {
 };
 
 struct event_constraint intel_slm_pebs_event_constraints[] = {
-	/* UOPS_RETIRED.ALL, inv=1, cmask=16 (cycles:p). */
-	INTEL_FLAGS_EVENT_CONSTRAINT(0x108001c2, 0xf),
+	/* INST_RETIRED.ANY_P, inv=1, cmask=16 (cycles:p). */
+	INTEL_FLAGS_EVENT_CONSTRAINT(0x108000c0, 0x1),
 	/* Allow all events as PEBS with no flags */
 	INTEL_ALL_EVENT_CONSTRAINT(0, 0x1),
 	EVENT_CONSTRAINT_END
-- 
2.17.1