From c13f3757d0fcdcc2b7fc5d5e38da76b8913e6648 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 20 Jan 2012 15:36:33 -0800 Subject: rcu: Add CPU-stall capability to rcutorture Add module parameters to rcutorture that induce a CPU stall. The stall_cpu parameter specifies how long to stall in seconds, defaulting to zero, which indicates no stalling is to be undertaken. The stall_cpu_holdoff parameter specifies how many seconds after insmod (or boot, if rcutorture is built into the kernel) that this stall is to start. The default value for stall_cpu_holdoff is ten seconds. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- Documentation/RCU/torture.txt | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'Documentation/RCU') diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt index d25be872ae33..375d3fb71437 100644 --- a/Documentation/RCU/torture.txt +++ b/Documentation/RCU/torture.txt @@ -86,6 +86,24 @@ shutdown_secs The number of seconds to run the test before terminating zero, which disables test termination and system shutdown. This capability is useful for automated testing. +stall_cpu The number of seconds that a CPU should be stalled while + within both an rcu_read_lock() and a preempt_disable(). + This stall happens only once per rcutorture run. + If you need multiple stalls, use modprobe and rmmod to + repeatedly run rcutorture. The default for stall_cpu + is zero, which prevents rcutorture from stalling a CPU. + + Note that attempts to rmmod rcutorture while the stall + is ongoing will hang, so be careful what value you + choose for this module parameter! In addition, too-large + values for stall_cpu might well induce failures and + warnings in other parts of the kernel. You have been + warned! + +stall_cpu_holdoff + The number of seconds to wait after rcutorture starts + before stalling a CPU. Defaults to 10 seconds. + stat_interval The number of seconds between output of torture statistics (via printk()). Regardless of the interval, statistics are printed when the module is unloaded. -- cgit v1.2.3