rcutorture: Permit holding off CPU-hotplug operations during boot

When rcutorture is started automatically at boot time, it might well
also start CPU-hotplug operations at that time, which might not be
desirable.  This commit therefore adds an rcutorture parameter that
allows CPU-hotplug operations to be held off for the specified number
of seconds after the start of boot.

Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
This commit is contained in:
Paul E. McKenney 2012-01-17 14:36:51 -08:00 • committed by Paul E. McKenney
commit 9b9ec9b90e
2 changed files with 21 additions and 4 deletions

View file

@ -69,6 +69,13 @@ onoff_interval
CPU-hotplug operations regardless of what value is
specified for onoff_interval.
onoff_holdoff The number of seconds to wait until starting CPU-hotplug
operations. This would normally only be used when
rcutorture was built into the kernel and started
automatically at boot time, in which case it is useful
in order to avoid confusing boot-time code with CPUs
coming and going.
shuffle_interval
The number of seconds to keep the test threads affinitied
to a particular subset of the CPUs, defaults to 3 seconds.
@ -277,5 +284,7 @@ The following script may be used to torture RCU:
The output can be manually inspected for the error flag of "!!!".
One could of course create a more elaborate script that automatically
checked for such errors. The "rmmod" command forces a "SUCCESS" or
"FAILURE" indication to be printk()ed.
checked for such errors. The "rmmod" command forces a "SUCCESS",
"FAILURE", or "RCU_HOTPLUG" indication to be printk()ed. The first
two are self-explanatory, while the last indicates that while there
were no RCU failures, CPU-hotplug problems were detected.