>Number:         3221
>Category:       kern
>Synopsis:       problem with vnode_pager_sync
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Feb 16 15:35:01 1997
>Last-Modified:
>Originator:     Bernd Ernesti
>Organization:
	
>Release:        NetBSD-current 17-02-96 10pm GMT
>Environment:
	
System: NetBSD parresum 1.2C NetBSD 1.2C (VEEGO) #35: Sun Feb 16 22:51:05 MET 1997     bernd@parresum:/home/obj_i386/src/sys/arch/i386/compile/VEEGO i386

>Description:
	The new vnode_pager_sync call slows down disk speed for about
	3-10 times.
>How-To-Repeat:
	do a 'make' and 'make install' in src/gnu/usr.bin and hear what your
	disk do:

	cd /src/gnu/usr.bin/groff

	Kernel without vnode_pager_sync:
	time make install
	7.158u 16.341s 0:50.18 46.8% 0+0k 799+1862io 6708pf+0w

	Kernel with vnode_pager_sync:
	time make install
	7.366u 17.153s 3:55.64 10.4% 0+0k 17977+1976io 6036pf+0w

	The problem is that this happens not right after you booted a new
	kernel. Try to do an 'make install' for the hole NetBSD source tree
	and you notice when it slows down.

NetBSD 1.2C (VEEGO) #34: Sun Feb 16 19:12:33 MET 1997
    bernd@parresum:/home/obj_i386/src/sys/arch/i386/compile/VEEGO
cpu0: family 5 model 2 step c
cpu0: Intel Pentium (P54C) (586-class)
real mem  = 66711552
avail mem = 60149760
using 839 buffers containing 3436544 bytes of memory

>Fix:
	use the old revision of vm_extern.h, vnode_pager.c and vfs_syscalls.c
	or find the problem.
vfs_syscalls.c: /*   $NetBSD: vfs_syscalls.c,v 1.75 1997/02/10 12:41:19 fvdl Exp $   */
vm_extern.h:    /*   $NetBSD: vm_extern.h,v 1.23 1997/02/05 08:09:45 mrg Exp $       */
vnode_pager.c:  /*   $NetBSD: vnode_pager.c,v 1.22 1997/01/31 03:06:06 thorpej Exp $ */

>Audit-Trail:
>Unformatted: