linux-kernel - [RFC PATCH v5 12/16] perf stat: Handle NMI in hardware-grouping

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Message-ID: <20240412210756.309828-13-weilin.wang@intel.com>
Date: Fri, 12 Apr 2024 14:07:52 -0700
From: weilin.wang@...el.com
To: weilin.wang@...el.com,
	Ian Rogers <irogers@...gle.com>,
	Kan Liang <kan.liang@...ux.intel.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>
Cc: linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Perry Taylor <perry.taylor@...el.com>,
	Samantha Alt <samantha.alt@...el.com>,
	Caleb Biggers <caleb.biggers@...el.com>
Subject: [RFC PATCH v5 12/16] perf stat: Handle NMI in hardware-grouping

From: Weilin Wang <weilin.wang@...el.com>

Add an easy nmi watchdog support in grouping. When nmi watchdog is enabled,
we reduce the total num of events could be assigned to one group by 1. A
more efficient solution will be added in later.

Reviewed-by: Ian Rogers <irogers@...gle.com>
Signed-off-by: Weilin Wang <weilin.wang@...el.com>
---
 tools/perf/util/metricgroup.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index 9548654c9f6d..31036035484c 100644
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -1993,6 +1993,10 @@ static int insert_new_group(struct list_head *head,
 			   size_t counters_num_fixed)
 {
 	INIT_LIST_HEAD(&new_group->event_head);
+	if (sysctl__nmi_watchdog_enabled()) {
+		pr_debug("NMI watchdog is enabled. Reduce num of counters by 1\n");
+		counters_num_gp -= 1;
+	}
 	fill_counter_bitmap(new_group->gp_counters, 0, counters_num_gp);
 	fill_counter_bitmap(new_group->fixed_counters, 0, counters_num_fixed);
 	list_add_tail(&new_group->nd, head);
-- 
2.42.0