perf/x86/cqm: Fix CQM handling of grouping events into a cache_group
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>
diff --git a/arch/x86/events/intel/cqm.c b/arch/x86/events/intel/cqm.c
index 93cb412..b0226f1 100644
--- a/arch/x86/events/intel/cqm.c
+++ b/arch/x86/events/intel/cqm.c
@@ -281,9 +281,13 @@
/*
* 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 @@
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 @@
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 @@
* 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;
/*
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 79ec7bb..7bb315b 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -121,6 +121,7 @@
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;