Commit b5fe223a authored Apr 27, 2017 by Paul E. McKenney

srcu: Adjust default auto-expediting holdoff



The default value for the kernel boot parameter srcutree.exp_holdoff
is 50 microseconds, which is too long for good Tree SRCU performance
(compared to Classic SRCU) on the workloads tested by Mike Galbraith.
This commit therefore sets the default value to 25 microseconds, which
shows excellent results in Mike's testing.

Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Mike Galbraith <efault@gmx.de>

parent 96fd20cf

kernel/rcu/srcutree.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -39,7 +39,7 @@

		#include "rcu.h"

		ulong exp_holdoff = 50 * 1000; /* Holdoff (ns) for auto-expediting. */
		ulong exp_holdoff = 25 * 1000; /* Holdoff (ns) for auto-expediting. */
		module_param(exp_holdoff, ulong, 0444);

		static void srcu_invoke_callbacks(struct work_struct *work);