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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2016-01-30 20:56:38 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2016-03-31 13:38:58 -0700
commitdf37e66bfdbb57e8cae7dbf39a0c66b1b8701338 (patch)
tree76c3d3915b98d79870a54593530aa029f77a976e /kernel/rcu
parent2b03d038457fc8d694d34981cb0a2f1702ba35d6 (diff)
downloadlinux-sh-df37e66bfdbb57e8cae7dbf39a0c66b1b8701338.tar.gz
rcutorture: Add rcuperf holdoff boot parameter to reduce interference
Boot-time activity can legitimately grab CPUs for extended time periods, so the commit adds a boot parameter to delay the start of the performance test until boot has completed. Defaults to 10 seconds. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/rcuperf.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c
index 12561f96f0a2..278600143bb6 100644
--- a/kernel/rcu/rcuperf.c
+++ b/kernel/rcu/rcuperf.c
@@ -59,6 +59,7 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.vnet.ibm.com>");
do { if (verbose) pr_alert("%s" PERF_FLAG "!!! %s\n", perf_type, s); } while (0)
torture_param(bool, gp_exp, true, "Use expedited GP wait primitives");
+torture_param(int, holdoff, 10, "Holdoff time before test start (s)");
torture_param(int, nreaders, -1, "Number of RCU reader threads");
torture_param(int, nwriters, -1, "Number of RCU updater threads");
torture_param(bool, shutdown, false, "Shutdown at end of performance tests.");
@@ -368,6 +369,10 @@ rcu_perf_writer(void *arg)
set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
sp.sched_priority = 1;
sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
+
+ if (holdoff)
+ schedule_timeout_uninterruptible(holdoff * HZ);
+
t = ktime_get_mono_fast_ns();
if (atomic_inc_return(&n_rcu_perf_writer_started) >= nrealwriters) {
t_rcu_perf_writer_started = t;