For what it's worth, the 64-bit architecture, both prior to and with MIPS64, has always required that 64-bit GPRs be sign-extended when used with 32-bit operations. I'm surprised that this wasn't seen on more 64-bit CPUs than just the SB1. /gmu --- Michael Uhler, Chief Technology Officer MIPS Technologies, Inc. Email: uhler at mips.com 1225 Charleston Road Voice: (650)567-5025 Mountain View, CA 94043 > -----Original Message----- > From: linux-mips-bounce@xxxxxxxxxxxxxx > [mailto:linux-mips-bounce@xxxxxxxxxxxxxx] On Behalf Of Ralf Baechle > Sent: Tuesday, September 20, 2005 4:06 AM > To: Matej Kupljen > Cc: Maciej W. Rozycki; Daniel Jacobowitz; linux-mips@xxxxxxxxxxxxxx > Subject: Re: [PATCH] Fix TCP/UDP checksums on the Broadcom SB-1 > > > On Tue, Sep 20, 2005 at 01:00:04PM +0200, Matej Kupljen wrote: > > > > > This caused incorrect checksums in some UDP packets for > NFS root. > > > > The problem was mild when using a 10.0.1.x IP address, > but severe > > > > when using 192.168.1.x. > > > > > > Ah! So *that* is the reason for the absolutely abysmal NFS > > > performance > > > of the SWARM with 2.6! I have had no time to track it > down -- thanks a > > > lot! > > > > Is this for MIPS64 only? > > Because, on dbau1200 we also have poor NFS performance :-( > > It's for 64-bit kernels only. Note the difference, I didn't > say MIPS64. > > Also, since this bug did result in an operation that has > undefined behaviour it likely may will only have impacted > some 64-bit processors - such as the SB1 - but others may > have been unaffected. > > Ralf > >
