>Number:         15020
>Category:       kern
>Synopsis:       NFS gives FIFO underruns with sip0 on SiS630/735 chipsets
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Dec 21 01:44:00 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     The Super-User
>Release:        NetBSD 1.5.2
>Organization:
Precedence Technologies Ltd
>Environment:
	
System: NetBSD laptop 1.5Y NetBSD 1.5Y (LAPTOP) #4: Thu Dec 20 11:22:27 GMT 2001 root@laptop:/usr/src/sys/arch/i386/compile/LAPTOP i386


>Description:
When using a SiS 630/735 chipset with integrated ethernet, medium to
heavy NFS usage will give the following errors:
sip0: discarding oversize frame (len=2047)
sip0: transmit FIFO underrun: increasing Tx drain threshold to xxx bytes
(xxx increases by 32 each time)

At this point, NFS mounts will hang.
 
>How-To-Repeat:
ifconfig sip0 and NFS mount a directory. In this directory untar a
fair-sized tar file. For example, mount /usr/pkgsrc over NFS and try to build
x11/xworld.
>Fix:
Fix unknown. Mounting with -r 1024 -w 1024 will work around it, but give
slow NFS performance.
>Release-Note:
>Audit-Trail:
>Unformatted: