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Patch "perf/x86: Honor the architectural performance monitoring version" has been added to the 3.14-stable tree

PATCH [email protected] 1 participant 1 message Jul 25, 2016

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This is a note to let you know that I've just added the patch titled

perf/x86: Honor the architectural performance monitoring version

to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
perf-x86-honor-the-architectural-performance-monitoring-version.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 2c33645d366d13b969d936b68b9f4875b1fdddea Mon Sep 17 00:00:00 2001

From: "Palik, Imre" <[email protected]>
Date: Mon, 8 Jun 2015 14:46:49 +0200
Subject: perf/x86: Honor the architectural performance monitoring version

From: Palik, Imre <[email protected]>

commit 2c33645d366d13b969d936b68b9f4875b1fdddea upstream.

Architectural performance monitoring, version 1, doesn't support fixed counters.

Currently, even if a hypervisor advertises support for architectural performance monitoring version 1, perf may still try to use the fixed counters, as the constraints are set up based on the CPU model.

This patch ensures that perf honors the architectural performance monitoring version returned by CPUID, and it only uses the fixed counters for version 2 and above.

(Some of the ideas in this patch came from Peter Zijlstra.)

Signed-off-by Imre Palik <[email protected]>
Signed-off-by Peter Zijlstra (Intel) <[email protected]>
Cc Andrew Morton <[email protected]>
Cc Andy Lutomirski <[email protected]>
Cc Anthony Liguori <[email protected]>
Cc Arnaldo Carvalho de Melo <[email protected]>
Cc Borislav Petkov <[email protected]>
Cc Brian Gerst <[email protected]>
Cc Denys Vlasenko <[email protected]>
Cc H. Peter Anvin <[email protected]>
Cc Linus Torvalds <[email protected]>
Cc Oleg Nesterov <[email protected]>
Cc Paul Mackerras <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Thomas Gleixner <[email protected]>
Link http://lkml.kernel.org/r/[email protected] open here
Signed-off-by Ingo Molnar <[email protected]>
Cc Kevin Christopher <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 arch/x86/kernel/cpu/perf_event_intel.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)
arch/x86/kernel/cpu/perf_event_intel.c +6 -6
@@ -2606,13 +2606,13 @@ __init int intel_pmu_init(void)
 		 * counter, so do not extend mask to generic counters
 		 */
 		for_each_event_constraint(c, x86_pmu.event_constraints) {
-			if (c->cmask != FIXED_EVENT_FLAGS
-			    || c->idxmsk64 == INTEL_PMC_MSK_FIXED_REF_CYCLES) {
-				continue;
+			if (c->cmask == FIXED_EVENT_FLAGS
+			    && c->idxmsk64 != INTEL_PMC_MSK_FIXED_REF_CYCLES) {
+				c->idxmsk64 |= (1ULL << x86_pmu.num_counters) - 1;
 			}
-
-			c->idxmsk64 |= (1ULL << x86_pmu.num_counters) - 1;
-			c->weight += x86_pmu.num_counters;
+			c->idxmsk64 &=
+				~(~0UL << (INTEL_PMC_IDX_FIXED + x86_pmu.num_counters_fixed));
+			c->weight = hweight64(c->idxmsk64);
 		}
 	}

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/perf-x86-fix-undefined-shift-on-32-bit-kernels.patch queue-3.14/perf-x86-honor-the-architectural-performance-monitoring-version.patch