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authorDipankar Sarma <dipankar@in.ibm.com>2006-03-08 00:55:33 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-08 17:14:01 -0500
commit21a1ea9eb40411d4ee29448c53b9e4c0654d6ceb (patch)
tree86e4b681858ac562c953bd3ea3c038defd8ec4f4 /Documentation
parente2bab3d92486fb781f4d06f56339264ed1492392 (diff)
[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')
-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 75205391b335..bad5987c4727 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1284,6 +1284,19 @@ running once the system is up.
1284 New name for the ramdisk parameter. 1284 New name for the ramdisk parameter.
1285 See Documentation/ramdisk.txt. 1285 See Documentation/ramdisk.txt.
1286 1286
1287 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1288 RCU callbacks to process in one batch.
1289
1290 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1291 RCU callbacks over which batch limiting is disabled.
1292
1293 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1294 RCU callbacks below which batch limiting is re-enabled.
1295
1296 rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
1297 RCU callbacks to queued before forcing reschedule
1298 on all cpus.
1299
1287 rdinit= [KNL] 1300 rdinit= [KNL]
1288 Format: <full_path> 1301 Format: <full_path>
1289 Run specified binary instead of /init from the ramdisk, 1302 Run specified binary instead of /init from the ramdisk,