[PATCH tip/core/rcu 17/22] rcutorture: Change units of onoff_interval to jiffies

From: Paul E. McKenney
Date: Tue Jun 26 2018 - 13:13:03 EST


Some RCU bugs have been sensitive to the frequency of CPU-hotplug
operations, which have been gradually increased over time. But this
frequency is now at the one-second lower limit that can be specified using
the rcutorture.onoff_interval kernel parameter. This commit therefore
changes the units of rcutorture.onoff_interval from seconds to jiffies,
and also sets the value specified for this kernel parameter in the TREE03
rcutorture scenario to 200, which is 200 milliseconds for HZ=1000.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 4 ++--
kernel/rcu/rcutorture.c | 4 ++--
tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot | 2 +-
.../testing/selftests/rcutorture/configs/rcu/ver_functions.sh | 2 +-
4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index efc7aa7a0670..77bd3e635313 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3632,8 +3632,8 @@
Set time (s) after boot for CPU-hotplug testing.

rcutorture.onoff_interval= [KNL]
- Set time (s) between CPU-hotplug operations, or
- zero to disable CPU-hotplug testing.
+ Set time (jiffies) between CPU-hotplug operations,
+ or zero to disable CPU-hotplug testing.

rcutorture.shuffle_interval= [KNL]
Set task-shuffle interval (s). Shuffling tasks
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 0481c7286875..eb6d4915b4e6 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -87,7 +87,7 @@ torture_param(int, object_debug, 0,
"Enable debug-object double call_rcu() testing");
torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
torture_param(int, onoff_interval, 0,
- "Time between CPU hotplugs (s), 0=disable");
+ "Time between CPU hotplugs (jiffies), 0=disable");
torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
@@ -1889,7 +1889,7 @@ rcu_torture_init(void)
firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
if (firsterr)
goto unwind;
- firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
+ firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval);
if (firsterr)
goto unwind;
firsterr = rcu_torture_stall_init();
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot b/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot
index b79ddb9eb9e8..5c3213cc3ad7 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot
@@ -1,4 +1,4 @@
-rcutorture.onoff_interval=1 rcutorture.onoff_holdoff=30
+rcutorture.onoff_interval=200 rcutorture.onoff_holdoff=30
rcutree.gp_preinit_delay=12
rcutree.gp_init_delay=3
rcutree.gp_cleanup_delay=3
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh b/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh
index 24ec91041957..7bab8246392b 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh
+++ b/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh
@@ -39,7 +39,7 @@ rcutorture_param_onoff () {
if ! bootparam_hotplug_cpu "$1" && configfrag_hotplug_cpu "$2"
then
echo CPU-hotplug kernel, adding rcutorture onoff. 1>&2
- echo rcutorture.onoff_interval=3 rcutorture.onoff_holdoff=30
+ echo rcutorture.onoff_interval=1000 rcutorture.onoff_holdoff=30
fi
}

--
2.17.1