From mboxrd@z Thu Jan  1 00:00:00 1970
From: John Ronciak <john.ronciak@gmail.com>
Subject: Re: e1000 problem with NAPI?
Date: Tue, 1 Mar 2005 10:13:34 -0800
Message-ID: <56a8daef05030110137b712879@mail.gmail.com>
References: <20050301135931.GA14610@xi.wantstofly.org>
Reply-To: John Ronciak <john.ronciak@gmail.com>
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Cc: netdev@oss.sgi.com, hadi@cyberus.ca, robert.olsson@data.slu.se
To: Lennert Buytenhek <buytenh@wantstofly.org>
In-Reply-To: <20050301135931.GA14610@xi.wantstofly.org>
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Lennert,

It sounds like you are running into a bug we had with NAPI in that
e1000 driver.  Robert actually found it.  :-)  Please try the 5.7.6
driver available from Sourceforge.  It has the fixed NAPI code in it.

Let us know if this fixes the problem.

Thanks,
John


On Tue, 1 Mar 2005 14:59:31 +0100, Lennert Buytenhek
<buytenh@wantstofly.org> wrote:
> Hi all,
> 
> I'm seeing some strange issues with an e1000 NIC.  I'm flooding it
> with tinygrams from a packet generator and then abruptly stop the
> generator.  The last few packets from the burst don't come through
> until after two seconds.  Sometimes there are multiple trailing
> bursts, each of them separated by two seconds.
> 
> For example:  (The low 24 bits of the destination address are set
> to the packet sequence number by the generator.)
> 
> 14:44:19.649874 IP 10.10.0.0 > 1.4.10.11: [|tcp]
> 14:44:19.649878 IP 10.10.0.0 > 1.4.10.12: [|tcp]
> 14:44:19.649882 IP 10.10.0.0 > 1.4.10.13: [|tcp]
> 14:44:19.649887 IP 10.10.0.0 > 1.4.10.14: [|tcp]
> 14:44:19.649891 IP 10.10.0.0 > 1.4.10.15: [|tcp]
> 14:44:19.649895 IP 10.10.0.0 > 1.4.10.16: [|tcp]
> 14:44:19.649899 IP 10.10.0.0 > 1.4.10.17: [|tcp]
> 14:44:21.650293 IP 10.10.0.0 > 1.4.10.18: [|tcp]                <=== delayed
> 14:44:21.650303 IP 10.10.0.0 > 1.4.10.19: [|tcp]
> 14:44:21.650308 IP 10.10.0.0 > 1.4.10.20: [|tcp]
> 14:44:21.650312 IP 10.10.0.0 > 1.4.10.21: [|tcp]
> 14:44:21.650316 IP 10.10.0.0 > 1.4.10.22: [|tcp]
> 14:44:21.650320 IP 10.10.0.0 > 1.4.10.23: [|tcp]
> 14:44:21.650324 IP 10.10.0.0 > 1.4.10.24: [|tcp]
> 14:44:21.650328 IP 10.10.0.0 > 1.4.10.25: [|tcp]
> 14:44:21.650332 IP 10.10.0.0 > 1.4.10.26: [|tcp]
> 
> I wrote the packet generator code myself (ixp2400 platform), but I've
> verified that the packets do leave the generator back-to-back.  What's
> also strange is that when these trailing bursts come in, the interface
> statistics counters do not change -- the packets in the trailing bursts
> have already been counted by the time they show up in tcpdump.
> 
> Jamal suspects a NAPI 'rotting packet' issue, which doesn't sound all
> that unlikely.  (Oh, this is kernel 2.6.10-something with e1000 driver
> version "5.5.4-k2-NAPI".)
> 
> Ideas?
> 
> cheers,
> Lennert
> 
> 


-- 
Cheers,
John