Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 14 Jun 2022 07:33:50 -0700
In-Reply-To: <20220614143353.1559597-1-irogers@google.com>
Message-Id: <20220614143353.1559597-4-irogers@google.com>
Mime-Version: 1.0
References: <20220614143353.1559597-1-irogers@google.com>
Subject: [PATCH v2 3/6] perf cpumap: Compute mask size in constant time
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>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

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