RE: device polling takes more CPU hits??
From: Don Bowman (don_at_sandvine.com)
Date: 07/26/04
- Previous message: Don Bowman: "RE: device polling takes more CPU hits??"
- Maybe in reply to: James: "device polling takes more CPU hits??"
- Next in thread: Kelly Yancey: "RE: device polling takes more CPU hits??"
- Reply: Kelly Yancey: "RE: device polling takes more CPU hits??"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
To: 'Luigi Rizzo' <rizzo@icir.org>, Kelly Yancey <kbyanc@posi.net> Date: Mon, 26 Jul 2004 16:28:56 -0400
From: Luigi Rizzo [mailto:rizzo@icir.org]
> On Mon, Jul 26, 2004 at 01:18:46PM -0700, Kelly Yancey wrote:
> ...
> > Out of curiousity, what sort of testing did you do to
> arrive at these
> > settings? I did some testing a while back with a SmartBits
> box pumping
> > packets through a FreeBSD 2.8Ghz box configured to route
> between two em
> > gigabit interfaces; I found that changing the burst_max and
> each_burst
> > parameters had almost no effect on throughput (maximum 1%
> difference).
>
> fast boxes are pci-bus limited, not CPU limited(*) so
> changing the burst
> size (which basically amortizes some CPU costs) has little if any
> effect.
The PCI-X bus will probably be 64-bit 133MHz in this case,
the limit moves up to the P64H2 hub for large packets,
to the CPU for small packets. Polling becomes quite
critical to prevent livelock.
--don
_______________________________________________
freebsd-net@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-net
To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"
- Previous message: Don Bowman: "RE: device polling takes more CPU hits??"
- Maybe in reply to: James: "device polling takes more CPU hits??"
- Next in thread: Kelly Yancey: "RE: device polling takes more CPU hits??"
- Reply: Kelly Yancey: "RE: device polling takes more CPU hits??"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Relevant Pages
|
|