path: root/Documentation/RCU
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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-01-20 15:36:33 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-02-21 09:03:52 -0800
commitc13f3757d0fcdcc2b7fc5d5e38da76b8913e6648 (patch)
tree7ae68a12459fc4f18b87fa1a44239e29f82cd244 /Documentation/RCU
parent105617da8dc0ae3cf5f5a581330b1e4846fe87f2 (diff)
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 <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'Documentation/RCU')
1 files changed, 18 insertions, 0 deletions
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!
+ 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.

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