[PATCH V2 1/1] perf, x86: bug fix for cycles:p and cycles:pp on SLM

[PATCH V2 1/1] perf, x86: bug fix for cycles:p and cycles:pp on SLM

[kan.liang]

From: Kan Liang <kan.liang@intel.com>

cycles:p and cycles:pp do not work on SLM since
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 call intel_pebs_aliases_core2 which uses INST_RETIRED.ANY_P
counts 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, here only
INST_RETIRED.ANY_P, inv=1, cmask=16 need to specially handled.

Signed-off-by: Kan Liang <kan.liang@intel.com>
---
Changes since V1
 - Only handle INST_RETIRED.ANY_P, inv=1, cmask=16

 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 3c895d4..0739833 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
-- 
1.7.11.7

[tip:perf/urgent] perf/x86/intel: Fix bug for "cycles:p" and " cycles:pp" on SLM

[tip-bot for Kan Liang]

Commit-ID:  33636732dcd7cc738a5913bb730d663c6b03c8fb
Gitweb:     http://git.kernel.org/tip/33636732dcd7cc738a5913bb730d663c6b03c8fb
Author:     Kan Liang <kan.liang@intel.com>
AuthorDate: Mon, 12 Jan 2015 17:42:21 +0000
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 16 Jan 2015 09:06:59 +0100

perf/x86/intel: Fix bug for "cycles:p" and "cycles:pp" on SLM

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@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1421084541-31639-1-git-send-email-kan.liang@intel.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.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 3c895d4..0739833 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