Re: Hardware IP checksums

[Andrew Morton <andrewm@xxxxxxxxxx>]

Artur Skawina wrote:
> 
> > It appeared pretty useless. Jes noticed this first time,
> > I had to check this experimentally, and yes... No visible improvements.
> > HW checksum on transmit looks really not useful without zero copy.
> 
> for example on p2 the extra checksumming cost (vs a plain copy) is ~7%,
> and that's the worst case, ie everything cached. Add cache misses and
> the difference won't be visible...

Ah.  That's pretty convincing.  But it would be a huge win for zero-copy
Tx, as Alexey points out.  I need to pay a bit more attention to what's
happening on that front.

Thanks.

-- 
-akpm-