From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
mingo@kernel.org, jiangshanlai@gmail.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 5/5] torture: Make jitter.sh handle large systems
Date: Wed, 3 Mar 2021 16:29:55 -0800 [thread overview]
Message-ID: <20210304002955.24132-5-paulmck@kernel.org> (raw)
In-Reply-To: <20210304002919.GA24003@paulmck-ThinkPad-P72>
From: "Paul E. McKenney" <paulmck@kernel.org>
The current jitter.sh script expects cpumask bits to fit into whatever
the awk interpreter uses for an integer, which clearly does not hold for
even medium-sized systems these days. This means that on a large system,
only the first 32 or 64 CPUs (depending) are subjected to jitter.sh
CPU-time perturbations. This commit therefore computes a given CPU's
cpumask using text manipulation rather than arithmetic shifts.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
tools/testing/selftests/rcutorture/bin/jitter.sh | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/rcutorture/bin/jitter.sh b/tools/testing/selftests/rcutorture/bin/jitter.sh
index 188b864..3a856ec 100755
--- a/tools/testing/selftests/rcutorture/bin/jitter.sh
+++ b/tools/testing/selftests/rcutorture/bin/jitter.sh
@@ -67,10 +67,10 @@ do
srand(n + me + systime());
ncpus = split(cpus, ca);
curcpu = ca[int(rand() * ncpus + 1)];
- mask = lshift(1, curcpu);
- if (mask + 0 <= 0)
- mask = 1;
- printf("%#x\n", mask);
+ z = "";
+ for (i = 1; 4 * i <= curcpu; i++)
+ z = z "0";
+ print "0x" 2 ^ (curcpu % 4) z;
}' < /dev/null`
n=$(($n+1))
if ! taskset -p $cpumask $$ > /dev/null 2>&1
--
2.9.5
prev parent reply other threads:[~2021-03-04 1:08 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 0:29 [PATCH tip/core/rcu 0/5] Realtime-related RCU updates for v5.13 Paul E. McKenney
2021-03-04 0:29 ` [PATCH tip/core/rcu 1/5] rcu: Expedite deboost in case of deferred quiescent state paulmck
2021-03-04 0:29 ` [PATCH tip/core/rcu 2/5] rcutorture: Make TREE03 use real-time tree.use_softirq setting paulmck
2021-03-04 0:29 ` [PATCH tip/core/rcu 3/5] rcutorture: Fix testing of RCU priority boosting paulmck
2021-03-04 0:29 ` [PATCH tip/core/rcu 4/5] rcu: Make rcu_read_unlock_special() expedite strict grace periods paulmck
2021-03-04 0:29 ` paulmck [this message]
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