4.4-stable review patch. If anyone has any objections, please let me know.
------------------ [ 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 <[email protected]> [peterz: Changed hw_perf_event::is_group_event to an int] Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Reviewed-by: Tony Luck <[email protected]> Acked-by: Thomas Gleixner <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: David Ahern <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Matt Fleming <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: Vince Weaver <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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;
