Patch "[PATCH 104/135] perf/x86/cqm: Fix CQM handling of grouping events" has been added to the 4.4-stable tree

Patch "[PATCH 104/135] perf/x86/cqm: Fix CQM handling of grouping events" has been added to the 4.4-stable tree

[gregkh]

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

    [PATCH 104/135] perf/x86/cqm: Fix CQM handling of grouping events

to the 4.4-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:
     0104-perf-x86-cqm-Fix-CQM-handling-of-grouping-events-int.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 14f7272e474c54172b243755f2e5edb9e1b614cc Mon Sep 17 00:00:00 2001
From: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Date: Thu, 10 Mar 2016 15:32:07 -0800
Subject: [PATCH 104/135] perf/x86/cqm: Fix CQM handling of grouping events
 into a cache_group

[ Upstream commit a223c1c7ab4cc64537dc4b911f760d851683768a ]

Currently CQM (cache quality of service monitoring) is grouping all
events belonging to same PID to use one RMID. However its not counting
all of these different events. Hence we end up with a count of zero
for all events other than the group leader.

The patch tries to address the issue by keeping a flag in the
perf_event.hw which has other CQM related fields. The field is updated
at event creation and during grouping.

Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
[peterz: Changed hw_perf_event::is_group_event to an int]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: fenghua.yu@intel.com
Cc: h.peter.anvin@intel.com
Cc: ravi.v.shankar@intel.com
Cc: vikas.shivappa@intel.com
Link: http://lkml.kernel.org/r/1457652732-4499-2-git-send-email-vikas.shivappa@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/kernel/cpu/perf_event_intel_cqm.c |   13 ++++++++++---
 include/linux/perf_event.h                 |    1 +
 2 files changed, 11 insertions(+), 3 deletions(-)

--- a/arch/x86/kernel/cpu/perf_event_intel_cqm.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
@@ -281,9 +281,13 @@ static bool __match_event(struct perf_ev
 
 	/*
 	 * Events that target same task are placed into the same cache group.
+	 * Mark it as a multi event group, so that we update ->count
+	 * for every event rather than just the group leader later.
 	 */
-	if (a->hw.target == b->hw.target)
+	if (a->hw.target == b->hw.target) {
+		b->hw.is_group_event = true;
 		return true;
+	}
 
 	/*
 	 * Are we an inherited event?
@@ -849,6 +853,7 @@ static void intel_cqm_setup_event(struct
 	bool conflict = false;
 	u32 rmid;
 
+	event->hw.is_group_event = false;
 	list_for_each_entry(iter, &cache_groups, hw.cqm_groups_entry) {
 		rmid = iter->hw.cqm_rmid;
 
@@ -940,7 +945,9 @@ static u64 intel_cqm_event_count(struct
 		return __perf_event_count(event);
 
 	/*
-	 * Only the group leader gets to report values. This stops us
+	 * Only the group leader gets to report values except in case of
+	 * multiple events in the same group, we still need to read the
+	 * other events.This stops us
 	 * reporting duplicate values to userspace, and gives us a clear
 	 * rule for which task gets to report the values.
 	 *
@@ -948,7 +955,7 @@ static u64 intel_cqm_event_count(struct
 	 * specific packages - we forfeit that ability when we create
 	 * task events.
 	 */
-	if (!cqm_group_leader(event))
+	if (!cqm_group_leader(event) && !event->hw.is_group_event)
 		return 0;
 
 	/*
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -121,6 +121,7 @@ struct hw_perf_event {
 		struct { /* intel_cqm */
 			int			cqm_state;
 			u32			cqm_rmid;
+			int			is_group_event;
 			struct list_head	cqm_events_entry;
 			struct list_head	cqm_groups_entry;
 			struct list_head	cqm_group_entry;


Patches currently in stable-queue which might be from vikas.shivappa@linux.intel.com are

queue-4.4/0104-perf-x86-cqm-Fix-CQM-handling-of-grouping-events-int.patch
queue-4.4/0105-perf-x86-cqm-Fix-CQM-memory-leak-and-notifier-leak.patch