On Fri, 09 Dec 2022, Joel Fernandes (Google) wrote:
The rt boosting in locktorture has a factor variable s currently large enough
that boosting only happens once every minute or so. Add a tunable to reduce the
factor so that boosting happens more often, to test paths and arrive at failure
modes earlier. With this change, I can set the factor to like 50 and have the
boosting happens every 10 seconds or so.
Tested with boot parameters:
locktorture.torture_type=mutex_lock
locktorture.onoff_interval=1
locktorture.nwriters_stress=8
locktorture.stutter=0
locktorture.rt_boost=1
locktorture.rt_boost_factor=50
locktorture.nlocks=3
Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Reviewed-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>
---
kernel/locking/locktorture.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 8968fd65a90d..b64a528e511c 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -48,6 +48,7 @@ torture_param(int, stat_interval, 60,
torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
torture_param(int, rt_boost, 2,
"Do periodic rt-boost. 0=Disable, 1=Only for rt_mutex, 2=For all lock types.");
+torture_param(int, rt_boost_factor, 50, "A factor determining how often rt-boost happens.");
torture_param(int, verbose, 1,
"Enable verbose debugging printk()s");
torture_param(int, nlocks, 1,
@@ -133,12 +134,12 @@ static void torture_lock_busted_write_unlock(int tid __maybe_unused)
static void __torture_rt_boost(struct torture_random_state *trsp)
{
- const unsigned int factor = 50000; /* yes, quite arbitrary */
+ const unsigned int factor = rt_boost_factor;
if (!rt_task(current)) {
/*
- * Boost priority once every ~50k operations. When the
- * task tries to take the lock, the rtmutex it will account
+ * Boost priority once every rt_boost_factor operations. When
+ * the task tries to take the lock, the rtmutex it will account
Nit: maybe refer to it as 'rt_boost_factor'?
* for the new priority, and do any corresponding pi-dance.
*/
if (trsp && !(torture_random(trsp) %
@@ -148,8 +149,9 @@ static void __torture_rt_boost(struct torture_random_state *trsp)
return;
} else {
/*
- * The task will remain boosted for another ~500k operations,
- * then restored back to its original prio, and so forth.
+ * The task will remain boosted for another 10*rt_boost_factor
+ * operations, then restored back to its original prio, and so
+ * forth.
*
* When @trsp is nil, we want to force-reset the task for
* stopping the kthread.
--
2.39.0.rc1.256.g54fd8350bd-goog
