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| author |   Paul E. McKenney <paulmck@kernel.org> | 2021-02-10 13:25:58 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-03-08 14:21:41 -0800 |
| commit | 8126c57f00cea3502a017b7c76df1fac58f89e88 (patch) | |
| tree | c81e5682d92d418dff541a4d5d8ea20185a1224c | |
| parent | rcu: Make rcu_read_unlock_special() expedite strict grace periods (diff) | |
| download | linux-dev-8126c57f00cea3502a017b7c76df1fac58f89e88.tar.xz linux-dev-8126c57f00cea3502a017b7c76df1fac58f89e88.zip | |
torture: Make jitter.sh handle large systems
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>
| -rwxr-xr-x | tools/testing/selftests/rcutorture/bin/jitter.sh | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/tools/testing/selftests/rcutorture/bin/jitter.sh b/tools/testing/selftests/rcutorture/bin/jitter.sh index 188b864bc4bf..3a856ec2e92a 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 |