[PATCH 03/12] perf, tools, stat: Force --per-core mode for .aggr-per-core aliases

From: Andi Kleen
Date: Tue Jan 19 2016 - 21:28:46 EST


From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

When an event alias is used that the kernel marked as .aggr-per-core, force
--per-core mode (and also require -a and forbid cgroups or per thread mode).
This in term means, --topdown forces --per-core mode.

This is needed for TopDown in SMT mode, because it needs to measure
all threads in a core together and merge the values to compute the correct
percentages of how the pipeline is limited.

We do this if any alias is aggr-per-core.

The main stat code does the necessary checks and forces per core mode.

v2: Rename agg-per-core to aggr-per-core
v3: Split patch into parse and use
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
tools/perf/builtin-stat.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index b6dcafa..72bc9b4 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -2135,6 +2135,7 @@ static int __cmd_report(int argc, const char **argv)

int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
{
+ struct perf_evsel *counter;
const char * const stat_usage[] = {
"perf stat [<options>] [<command>]",
NULL
@@ -2276,6 +2277,23 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
if (add_default_attributes())
goto out;

+ evlist__for_each (evsel_list, counter) {
+ /* Enable per core mode if only a single event requires it. */
+ if (counter->aggr_per_core) {
+ if (stat_config.aggr_mode != AGGR_GLOBAL &&
+ stat_config.aggr_mode != AGGR_CORE) {
+ pr_err("per core event configuration requires per core mode\n");
+ goto out;
+ }
+ stat_config.aggr_mode = AGGR_CORE;
+ if (nr_cgroups || !target__has_cpu(&target)) {
+ pr_err("per core event configuration requires system-wide mode (-a)\n");
+ goto out;
+ }
+ break;
+ }
+ }
+
target__validate(&target);

if (perf_evlist__create_maps(evsel_list, &target) < 0) {
--
2.4.3