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Re: [E1000-devel] Transmission limit

To: Scott Feldman <sfeldma@xxxxxxxxx>
Subject: Re: [E1000-devel] Transmission limit
From: Lennert Buytenhek <buytenh@xxxxxxxxxxxxxx>
Date: Wed, 1 Dec 2004 22:35:50 +0100
Cc: jamal <hadi@xxxxxxxxxx>, Robert Olsson <Robert.Olsson@xxxxxxxxxxx>, P@xxxxxxxxxxxxxx, mellia@xxxxxxxxxxxxxxxxxxxx, e1000-devel@xxxxxxxxxxxxxxxxxxxxx, Jorge Manuel Finochietto <jorge.finochietto@xxxxxxxxx>, Giulio Galante <galante@xxxxxxxxx>, netdev@xxxxxxxxxxx
In-reply-to: <20041201182943.GA14470@xi.wantstofly.org>
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On Wed, Dec 01, 2004 at 07:29:43PM +0100, Lennert Buytenhek wrote:

> > This doubles the kpps numbers for 60-byte packets.  I'd like to see what
> > happens on higher bus bandwidth systems.  Anyone?
> 
> Dual Xeon 2.4GHz, a 82540EM and a 82541GI both on 32/66 on separate
> PCI buses.
> 
> BEFORE performance is approx the same for both, ~620kpps.
> AFTER performance is ~730kpps, also approx the same for both.

Pretty graph attached.  From ~220B packets or so it does wire speed, but
there's still an odd drop in performance around 256B packets (which is
also there without your patch.)  From 350B packets or so, performance is
identical with or without your patch (wire speed.)

So.  Do you have any other good plans perhaps? :)


> Once or twice it went into a state where it started spitting out these
> kinds of messages and never recovered:
> 
>       Dec  1 19:13:18 phi kernel: NETDEV WATCHDOG: eth1: transmit timed out
>       [...]
>       Dec  1 19:13:31 phi kernel: NETDEV WATCHDOG: eth1: transmit timed out
>       [...]
>       Dec  1 19:13:43 phi kernel: NETDEV WATCHDOG: eth1: transmit timed out

Didn't see this happen anymore.  (ifconfig down and then up recovered it
both times I saw it happen.)


thanks,
Lennert

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