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From: Ian Rogers <irogers@google.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	James Clark <james.clark@arm.com>,
	Kees Cook <keescook@chromium.org>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Riccardo Mancini <rickyman7@gmail.com>,
	German Gomez <german.gomez@arm.com>,
	Colin Ian King <colin.king@intel.com>,
	Song Liu <songliubraving@fb.com>,
	Dave Marchevsky <davemarchevsky@fb.com>,
	Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
	Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>,
	Leo Yan <leo.yan@linaro.org>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Stephane Eranian <eranian@google.com>, Ian Rogers <irogers@google.com>
Subject: [PATCH 3/6] perf cpumap: Compute mask size in constant time
Date: Mon, 13 Jun 2022 01:47:36 -0700	[thread overview]
Message-ID: <20220613084739.1159111-4-irogers@google.com> (raw)
In-Reply-To: <20220613084739.1159111-1-irogers@google.com>

perf_cpu_map__max computes the cpumap's maximum value, no need to
iterate over all values.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/synthetic-events.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index b8a42a096502..0d87df20ec44 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -1213,18 +1213,7 @@ static size_t cpus_size(const struct perf_cpu_map *map)
 
 static size_t mask_size(const struct perf_cpu_map *map, int *max)
 {
-	int i;
-
-	*max = 0;
-
-	for (i = 0; i < perf_cpu_map__nr(map); i++) {
-		/* bit position of the cpu is + 1 */
-		int bit = perf_cpu_map__cpu(map, i).cpu + 1;
-
-		if (bit > *max)
-			*max = bit;
-	}
-
+	*max = perf_cpu_map__max(map).cpu;
 	return sizeof(struct perf_record_record_cpu_map) + BITS_TO_LONGS(*max) * sizeof(long);
 }
 
-- 
2.36.1.476.g0c4daa206d-goog


  parent reply	other threads:[~2022-06-13  8:48 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-13  8:47 [PATCH 0/6] Corrections to cpu map event encoding Ian Rogers
2022-06-13  8:47 ` [PATCH 1/6] perf cpumap: Const map for max Ian Rogers
2022-06-13  8:47 ` [PATCH 2/6] perf cpumap: Synthetic events and const/static Ian Rogers
2022-06-13  8:47 ` Ian Rogers [this message]
2022-06-13  8:47 ` [PATCH 4/6] perf cpumap: Fix alignment for masks in event encoding Ian Rogers
2022-06-13  8:47 ` [PATCH 5/6] perf events: Prefer union over variable length array Ian Rogers
2022-06-13  8:47 ` [PATCH 6/6] perf cpumap: Add range data encoding Ian Rogers

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