Commit-ID: 64e4b43ae050146fcfafe696e61efc306f73d449
Gitweb: http://git.kernel.org/tip/64e4b43ae050146fcfafe696e61efc306f73d449
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Wed, 12 Mar 2014 10:26:35 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Wed, 14 May 2014 09:46:13 -0700
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@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
---
kernel/rcu/rcutorture.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 37ae5e1..693a90f 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -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. */
--
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