This patch allows you to set the frequency with which the syncer runs
by setting SYNCER_MAXDELAY in the kernel configuration file, and
altering the sysctls kern.syncdelay, kern.filedelay, kern.dirdelay,
and kern.metadelay.

--- /usr/src/sys/kern/vfs_subr.c.orig	Thu Jul 27 06:54:38 2000
+++ /usr/src/sys/kern/vfs_subr.c	Thu Jul 27 06:55:51 2000
@@ -43,6 +43,7 @@
  * External virtual filesystem routines
  */
 #include "opt_ddb.h"
+#include "opt_syncdelay.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -133,9 +134,12 @@
 /*
  * The workitem queue.
  */
+#ifndef SYNCER_MAXDELAY
 #define SYNCER_MAXDELAY		32
+#endif
 static int syncer_maxdelay = SYNCER_MAXDELAY;	/* maximum delay time */
 time_t syncdelay = 30;		/* max time to delay syncing data */
+SYSCTL_INT(_kern, OID_AUTO, syncdelay, CTLFLAG_RW, &syncdelay, 0, "");
 time_t filedelay = 30;		/* time to delay syncing files */
 SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0, "");
 time_t dirdelay = 29;		/* time to delay syncing directories */
--- /usr/src/sys/conf/options.orig	Thu Jul 27 07:01:11 2000
+++ /usr/src/sys/conf/options	Thu Jul 27 07:01:31 2000
@@ -77,6 +77,7 @@
 UCONSOLE
 ICMP_BANDLIM
 VFS_AIO
+SYNCER_MAXDELAY	opt_syncdelay.h
 
 # POSIX kernel options
 P1003_1B			opt_posix.h