Subject: Re: PF_PACKET ???
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Alfred Perlstein <bright@mu.org>
List: tech-net
Date: 11/21/2001 17:53:30
* der Mouse <mouse@Rodents.Montreal.QC.CA> [011121 17:30] wrote:
> > To 'shovel' 10Mb ethernet across the ISA bus means moving a byte
> > every 800ns.  I can't remember the exact figure, but a typical ISA
> > bus cycle is around 600ns (some of the cards I've seen actually add
> > wait states!).  So for an 8-bit card the data transfer takes 75% of
> > your cpu time -
> 
> Shouldn't that be "75% of your bus bandwidth"?

No, 100% of your ISA bus bandwidth, probably some thing like
10% of your CPU<->memory bus bandwidth, and 75% of your CPU
time spent stalled in IO.

-- 
-Alfred Perlstein [alfred@freebsd.org]
'Instead of asking why a piece of software is using "1970s technology,"
 start asking why software is ignoring 30 years of accumulated wisdom.'
                           http://www.morons.org/rants/gpl-harmful.php3