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Re: [Fwd: Re: possible bug x86 2.4.2 SMP in IP receive stack]

To: andrewm@xxxxxxxxxx, kuznet@xxxxxxxxxxxxx
Subject: Re: [Fwd: Re: possible bug x86 2.4.2 SMP in IP receive stack]
From: Bob Felderman <feldy@xxxxxxxx>
Date: Wed, 7 Mar 2001 10:34:19 -0800 (PST)
Cc: davem@xxxxxxxxxx, feldy@xxxxxxxx, netdev@xxxxxxxxxxx, pp@xxxxxxxxxxxxxx
Sender: owner-netdev@xxxxxxxxxxx
=> > So you're saying that you can reproduce this crash with acenic?
=> 
=> Yes, I found capital logical bug there. Evictor on smp can corrupt queues.
=> Shame on me, I _knew_ that this pattern is wrong, socket hash tables need
=> the same, but they are right. So, fix is to work like sockets.
=> 
=> Patch is appended. Please, test.
=> 
=> Alexey


The patch appears to fix the problems I was seeing.
I've been blasting UDP streams at the smp box for
an hour or so. It used to die in a few seconds.
I'm also not seeing the RX-ERR increment at all. I was 
often not able to get an skb. Definitely a BIG 
improvement from my perspective - Thanks!
I'll be doing some more performance characterization
shortly. At first glance, I think the udp receive rate
is down quite a bit.


rcc2 33% netstat -i
Kernel Interface table
Iface   MTU Met    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0   1500   0     4834      0      0      0      607      0      0      0 BRU
lo    16192   0       46      0      0      0       46      0      0      0 LRU
myri0  9000   0 133058589      0      0      0     2867      0      0      0 BRU

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