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authorDipankar Sarma <dipankar@in.ibm.com>2006-03-07 21:55:33 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-08 14:14:01 -0800
commit21a1ea9eb40411d4ee29448c53b9e4c0654d6ceb (patch)
tree86e4b681858ac562c953bd3ea3c038defd8ec4f4 /Documentation/kernel-parameters.txt
parente2bab3d92486fb781f4d06f56339264ed1492392 (diff)
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[PATCH] rcu batch tuning
This patch adds new tunables for RCU queue and finished batches. There are two types of controls - number of completed RCU updates invoked in a batch (blimit) and monitoring for high rate of incoming RCUs on a cpu (qhimark, qlowmark). By default, the per-cpu batch limit is set to a small value. If the input RCU rate exceeds the high watermark, we do two things - force quiescent state on all cpus and set the batch limit of the CPU to INTMAX. Setting batch limit to INTMAX forces all finished RCUs to be processed in one shot. If we have more than INTMAX RCUs queued up, then we have bigger problems anyway. Once the incoming queued RCUs fall below the low watermark, the batch limit is set to the default. Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
-rw-r--r--Documentation/kernel-parameters.txt13
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 75205391..bad5987 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1284,6 +1284,19 @@ running once the system is up.
New name for the ramdisk parameter.
See Documentation/ramdisk.txt.
+ rcu.blimit= [KNL,BOOT] Set maximum number of finished
+ RCU callbacks to process in one batch.
+
+ rcu.qhimark= [KNL,BOOT] Set threshold of queued
+ RCU callbacks over which batch limiting is disabled.
+
+ rcu.qlowmark= [KNL,BOOT] Set threshold of queued
+ RCU callbacks below which batch limiting is re-enabled.
+
+ rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
+ RCU callbacks to queued before forcing reschedule
+ on all cpus.
+
rdinit= [KNL]
Format: <full_path>
Run specified binary instead of /init from the ramdisk,
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