From: "Michael Uhler" <uhler@mips.com>
To: "'Ralf Baechle'" <ralf@linux-mips.org>,
"'Matej Kupljen'" <matej.kupljen@ultra.si>
Cc: "'Maciej W. Rozycki'" <macro@linux-mips.org>,
"'Daniel Jacobowitz'" <dan@debian.org>,
<linux-mips@linux-mips.org>
Subject: RE: [PATCH] Fix TCP/UDP checksums on the Broadcom SB-1
Date: Tue, 20 Sep 2005 07:26:54 -0700 [thread overview]
Message-ID: <00da01c5bdef$596ee380$0502a8c0@MIPS.COM> (raw)
In-Reply-To: <20050920110609.GB3159@linux-mips.org>
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@linux-mips.org
> [mailto:linux-mips-bounce@linux-mips.org] On Behalf Of Ralf Baechle
> Sent: Tuesday, September 20, 2005 4:06 AM
> To: Matej Kupljen
> Cc: Maciej W. Rozycki; Daniel Jacobowitz; linux-mips@linux-mips.org
> 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
>
>
WARNING: multiple messages have this Message-ID (diff)
From: "Michael Uhler" <uhler@mips.com>
To: 'Ralf Baechle' <ralf@linux-mips.org>,
'Matej Kupljen' <matej.kupljen@ultra.si>
Cc: "'Maciej W. Rozycki'" <macro@linux-mips.org>,
'Daniel Jacobowitz' <dan@debian.org>,
linux-mips@linux-mips.org
Subject: RE: [PATCH] Fix TCP/UDP checksums on the Broadcom SB-1
Date: Tue, 20 Sep 2005 07:26:54 -0700 [thread overview]
Message-ID: <00da01c5bdef$596ee380$0502a8c0@MIPS.COM> (raw)
Message-ID: <20050920142654.9GRbgOxWKk277fDDxTBYiX-rWUPyAuZZWx8l_v3KX8g@z> (raw)
In-Reply-To: <20050920110609.GB3159@linux-mips.org>
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@linux-mips.org
> [mailto:linux-mips-bounce@linux-mips.org] On Behalf Of Ralf Baechle
> Sent: Tuesday, September 20, 2005 4:06 AM
> To: Matej Kupljen
> Cc: Maciej W. Rozycki; Daniel Jacobowitz; linux-mips@linux-mips.org
> 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
>
>
next prev parent reply other threads:[~2005-09-20 14:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-20 3:28 [PATCH] Fix TCP/UDP checksums on the Broadcom SB-1 Daniel Jacobowitz
2005-09-20 10:43 ` Maciej W. Rozycki
2005-09-20 11:00 ` Matej Kupljen
2005-09-20 11:06 ` Ralf Baechle
2005-09-20 14:26 ` Michael Uhler [this message]
2005-09-20 14:26 ` Michael Uhler
2005-09-20 14:59 ` Ralf Baechle
2005-09-20 11:01 ` Ralf Baechle
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