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rcutorture: Make rcu_torture_reader() use cond_resched() 

The rcu_torture_reader() function currently uses schedule().  This commit
therefore speeds things up a bit by substituting cond_resched().
This change makes rcu_torture_reader() more CPU-bound, so this commit
also adjusts the number of readers (the "nreaders" module parameter,
which feeds into the "nrealreaders" variable) to allow one CPU to be
free of readers on SMP systems.  The point of this is to increase the
probability that readers will be watching while an updater makes a change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit is contained in:
Paul E. McKenney 2014-03-12 10:26:35 -07:00
parent ac1bea8578
commit 64e4b43ae0
1 changed files with 7 additions and 4 deletions
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11
kernel/rcu/rcutorture.c
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@ -942,7 +942,7 @@ rcu_torture_reader(void *arg)
__this_cpu_inc(rcu_torture_batch[completed]);
preempt_enable();
cur_ops->readunlock(idx);
schedule();
cond_resched();
stutter_wait("rcu_torture_reader");
} while (!torture_must_stop());
if (irqreader && cur_ops->irq_capable)
@ -1482,10 +1482,13 @@ rcu_torture_init(void)
if (cur_ops->init)
cur_ops->init(); /* no "goto unwind" prior to this point!!! */
if (nreaders >= 0)
if (nreaders >= 0) {
nrealreaders = nreaders;
else
nrealreaders = 2 * num_online_cpus();
} else {
nrealreaders = num_online_cpus() - 1;
if (nrealreaders <= 0)
nrealreaders = 1;
}
rcu_torture_print_module_parms(cur_ops, "Start of test");
/* Set up the freelist. */