linux-kernel - [PATCH 06/11] perf, tools, stat: Force --per-core mode for .aggr-per-core aliases

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Message-Id: <1461787251-6702-7-git-send-email-andi@firstfloor.org>
Date:	Wed, 27 Apr 2016 13:00:46 -0700
From:	Andi Kleen <andi@...stfloor.org>
To:	acme@...nel.org
Cc:	peterz@...radead.org, jolsa@...nel.org,
	linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>
Subject: [PATCH 06/11] perf, tools, stat: Force --per-core mode for .aggr-per-core aliases

From: Andi Kleen <ak@...ux.intel.com>

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@...ux.intel.com>
---
 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 1f19f2f999c8..447a434d23bc 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -2156,6 +2156,7 @@ 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
@@ -2299,6 +2300,23 @@ 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) {
-- 
2.5.5