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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2008-06-25 12:24:52 -0700
committerIngo Molnar <mingo@elte.hu>2008-06-26 09:24:33 +0200
commit0729fbf3bc70870370b4f43d652f05a468dc68b8 (patch)
tree92557b04b368fac084f59d8397c32c5461ac26fd /Documentation/RCU/torture.txt
parent9a13150109fb418c50fa400c012f90d0ce6f67c3 (diff)
downloadlinux-linaro-stable-0729fbf3bc70870370b4f43d652f05a468dc68b8.tar.gz
rcu: make rcutorture even more vicious: invoke RCU readers from irq handlers (timers)
This patch allows torturing RCU from irq handlers (timers, in this case). A new module parameter irqreader enables such additional torturing, and is enabled by default. Variants of RCU that do not tolerate readers being called from irq handlers (e.g., SRCU) ignore irqreader. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: josh@freedesktop.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: dino@in.ibm.com Cc: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org Cc: vegard.nossum@gmail.com Cc: adobriyan@gmail.com Cc: oleg@tv-sign.ru Cc: bunk@kernel.org Cc: rjw@sisk.pl Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation/RCU/torture.txt')
-rw-r--r--Documentation/RCU/torture.txt23
1 files changed, 14 insertions, 9 deletions
diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt
index 516527d4bc55..a342b6e1cc10 100644
--- a/Documentation/RCU/torture.txt
+++ b/Documentation/RCU/torture.txt
@@ -30,10 +30,10 @@ MODULE PARAMETERS
This module has the following parameters:
-nreaders This is the number of RCU reading threads supported.
- The default is twice the number of CPUs. Why twice?
- To properly exercise RCU implementations with preemptible
- read-side critical sections.
+irqreaders Says to invoke RCU readers from irq level. This is currently
+ done via timers. Defaults to "1" for variants of RCU that
+ permit this. (Or, more accurately, variants of RCU that do
+ -not- permit this know to ignore this variable.)
nfakewriters This is the number of RCU fake writer threads to run. Fake
writer threads repeatedly use the synchronous "wait for
@@ -44,6 +44,16 @@ nfakewriters This is the number of RCU fake writer threads to run. Fake
to trigger special cases caused by multiple writers, such as
the synchronize_srcu() early return optimization.
+nreaders This is the number of RCU reading threads supported.
+ The default is twice the number of CPUs. Why twice?
+ To properly exercise RCU implementations with preemptible
+ read-side critical sections.
+
+shuffle_interval
+ The number of seconds to keep the test threads affinitied
+ to a particular subset of the CPUs, defaults to 3 seconds.
+ Used in conjunction with test_no_idle_hz.
+
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.
@@ -51,11 +61,6 @@ stat_interval The number of seconds between output of torture
be printed -only- when the module is unloaded, and this
is the default.
-shuffle_interval
- The number of seconds to keep the test threads affinitied
- to a particular subset of the CPUs, defaults to 3 seconds.
- Used in conjunction with test_no_idle_hz.
-
stutter The length of time to run the test before pausing for this
same period of time. Defaults to "stutter=5", so as
to run and pause for (roughly) five-second intervals.