linux-kernel - [PATCH] perf: cs-etm: Optimize option setup for CPU-wide sessions

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Date:   Tue, 11 Jun 2019 14:45:28 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     acme@...nel.org
Cc:     suzuki.poulose@....com, peterz@...radead.org, mingo@...hat.com,
        alexander.shishkin@...ux.intel.com, jolsa@...hat.com,
        namhyung@...nel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] perf: cs-etm: Optimize option setup for CPU-wide sessions

Call function cs_etm_set_option() once with all relevant options set rather
than multiple times to avoid going through the list of CPU more than once.

Suggested-by: Suzuki K Poulose <suzuki.poulose@....com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
---
 tools/perf/arch/arm/util/cs-etm.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
index 279c69caef91..c6f1ab5499b5 100644
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -162,20 +162,19 @@ static int cs_etm_set_option(struct auxtrace_record *itr,
 		    !cpu_map__has(online_cpus, i))
 			continue;
 
-		switch (option) {
-		case ETM_OPT_CTXTID:
+		if (option & ETM_OPT_CTXTID) {
 			err = cs_etm_set_context_id(itr, evsel, i);
 			if (err)
 				goto out;
-			break;
-		case ETM_OPT_TS:
+		}
+		if (option & ETM_OPT_TS) {
 			err = cs_etm_set_timestamp(itr, evsel, i);
 			if (err)
 				goto out;
-			break;
-		default:
-			goto out;
 		}
+		if (option & ~(ETM_OPT_CTXTID | ETM_OPT_TS))
+			/* Nothing else is currently supported */
+			goto out;
 	}
 
 	err = 0;
@@ -398,11 +397,8 @@ static int cs_etm_recording_options(struct auxtrace_record *itr,
 	if (!cpu_map__empty(cpus)) {
 		perf_evsel__set_sample_bit(cs_etm_evsel, CPU);
 
-		err = cs_etm_set_option(itr, cs_etm_evsel, ETM_OPT_CTXTID);
-		if (err)
-			goto out;
-
-		err = cs_etm_set_option(itr, cs_etm_evsel, ETM_OPT_TS);
+		err = cs_etm_set_option(itr, cs_etm_evsel,
+					ETM_OPT_CTXTID | ETM_OPT_TS);
 		if (err)
 			goto out;
 	}
-- 
2.11.0