rcutorture: Change units of onoff_interval to jiffies

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@linux.vnet.ibm.com>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index efc7aa7..77bd3e6 100644 (file)
--- 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 0481c72..eb6d491 100644 (file)
--- 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 b79ddb9..5c3213c 100644 (file)
--- 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 24ec910..7bab824 100644 (file)
--- 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
 }