svn commit: r247549 - projects/calloutng/sys/kern

[Alexander Motin]

Author: mav
Date: Fri Mar  1 15:09:23 2013
New Revision: 247549
URL: http://svnweb.freebsd.org/changeset/base/247549

Log:
  Change CC_HASH_SHIFT from 10 to 8, changing callwheel bucket size from 1ms
  to 4ms.  This allows to reduce time consumed by callout_process() on linear
  travense through the array of empty buckets on systems with few callouts.
  On systems with many callouts result depends on callouts time and precision:
  smaller CC_HASH_SHIFT value improves handling of long callouts, while bigger
  value improves handling of short and precise (not aggregable) ones.

Modified:
  projects/calloutng/sys/kern/kern_timeout.c

Modified: projects/calloutng/sys/kern/kern_timeout.c
==============================================================================
--- projects/calloutng/sys/kern/kern_timeout.c	Fri Mar  1 14:54:37 2013	(r247548)
+++ projects/calloutng/sys/kern/kern_timeout.c	Fri Mar  1 15:09:23 2013	(r247549)
@@ -367,7 +367,7 @@ start_softclock(void *dummy)
 
 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL);
 
-#define	CC_HASH_SHIFT	10
+#define	CC_HASH_SHIFT	8
 
 static inline u_int
 callout_hash(sbintime_t sbt)