From f885b7f2b2de70be266d2cecc476f773a1e2ca5d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 23 Apr 2012 15:52:53 -0700 Subject: rcu: Control RCU_FANOUT_LEAF from boot-time parameter Although making RCU_FANOUT_LEAF a kernel configuration parameter rather than a fixed constant makes it easier for people to decrease cache-miss overhead for large systems, it is of little help for people who must run a single pre-built kernel binary. This commit therefore allows the value of RCU_FANOUT_LEAF to be increased (but not decreased!) via a boot-time parameter named rcutree.rcu_fanout_leaf. Reported-by: Mike Galbraith Signed-off-by: Paul E. McKenney --- Documentation/kernel-parameters.txt | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation/kernel-parameters.txt') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index a92c5ebf373..12783fa833c 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2367,6 +2367,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Set maximum number of finished RCU callbacks to process in one batch. + rcutree.fanout_leaf= [KNL,BOOT] + Increase the number of CPUs assigned to each + leaf rcu_node structure. Useful for very large + systems. + rcutree.qhimark= [KNL,BOOT] Set threshold of queued RCU callbacks over which batch limiting is disabled. -- cgit v1.2.3