Re: [Bonding-devel] Re: [RFC][bonding] Improve VLAN support on top of bonding

[Ralph Doncaster <ralph@xxxxxxxxx>]

On Tue, 15 Jul 2003, Jeff Garzik wrote:

> Ralph Doncaster wrote:
> > On Tue, 15 Jul 2003, Dan Hollis wrote:
> >
> >
> >>That is exactly what it does. hw tcp checksumming helps a LOT at gbe rates
> >
> >
> > This still doesn't make any sense.  The copy from user-space to kernel
> > space does the checksum as far as I recall (unless you use the
> > router-not-host kernel build option).
>
>
> Not for the zero-copy case.

How common is this?  As far as I can tell, Apache 1.3 doesn't use sendfile
(you need 2.0 for that).  And even if 1.3 is using EnableMMAP with a large
write, you're limited to the size of SO_SNDBUF (or maybe only a single
page?).

This is not to say hw csum is a bad thing.  I think the linux IP stack
should support it.  When I was looking at the 2.4.19 code I noticed the
3c59x driver code supported hw csum, but I couldn't find anything in the
IP stack that used the csum flags set by the driver...

-Ralph