linux-kernel - [PATCH rcu 16/21] torture: Use numeric taskset argument in jitter.sh

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Message-Id: <20210721210140.787717-16-paulmck@kernel.org>
Date:   Wed, 21 Jul 2021 14:01:35 -0700
From:   "Paul E. McKenney" <paulmck@...nel.org>
To:     rcu@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, kernel-team@...com, mingo@...nel.org,
        jiangshanlai@...il.com, akpm@...ux-foundation.org,
        mathieu.desnoyers@...icios.com, josh@...htriplett.org,
        tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org,
        dhowells@...hat.com, edumazet@...gle.com, fweisbec@...il.com,
        oleg@...hat.com, joel@...lfernandes.org,
        "Paul E. McKenney" <paulmck@...nel.org>
Subject: [PATCH rcu 16/21] torture: Use numeric taskset argument in jitter.sh

The jitter.sh script has some entertaining awk code to generate a
hex mask from a randomly selected CPU number, which is handed to the
"taskset" command.  Except that this command has a "-c" parameter to
take a comma/dash-separated list of CPU numbers.  This commit therefore
saves a few lines of awk by switching to a single-number CPU list.

Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
 tools/testing/selftests/rcutorture/bin/jitter.sh | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/rcutorture/bin/jitter.sh b/tools/testing/selftests/rcutorture/bin/jitter.sh
index 15d937ba96cad..fd1ffaa5a1358 100755
--- a/tools/testing/selftests/rcutorture/bin/jitter.sh
+++ b/tools/testing/selftests/rcutorture/bin/jitter.sh
@@ -68,16 +68,12 @@ do
 	cpumask=`awk -v cpus="$cpus" -v me=$me -v n=$n 'BEGIN {
 		srand(n + me + systime());
 		ncpus = split(cpus, ca);
-		curcpu = ca[int(rand() * ncpus + 1)];
-		z = "";
-		for (i = 1; 4 * i <= curcpu; i++)
-			z = z "0";
-		print "0x" 2 ^ (curcpu % 4) z;
+		print ca[int(rand() * ncpus + 1)];
 	}' < /dev/null`
 	n=$(($n+1))
-	if ! taskset -p $cpumask $$ > /dev/null 2>&1
+	if ! taskset -c -p $cpumask $$ > /dev/null 2>&1
 	then
-		echo taskset failure: '"taskset -p ' $cpumask $$ '"'
+		echo taskset failure: '"taskset -c -p ' $cpumask $$ '"'
 		exit 1
 	fi
 
-- 
2.31.1.189.g2e36527f23