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From: Anton Titov <a.titov@host.bg>
To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Bad network performance over 2Gbps
Date: Tue, 15 Apr 2008 21:06:44 +0300	[thread overview]
Message-ID: <1208282804.23631.27.camel@localhost> (raw)

I use Linux for serving a huge amount of static web on few servers. When
network traffic goes above 2Gbit/sec ksoftirqd/5 (not every time 5, but
every time just one) starts using exactly 100% CPU time and packet
packet loss starts preventing traffic from going up. When the network
traffic is lower than 1.9Gbit ksoftirqds use 0% CPU according to top.

Uplink is 6 gigabit Intel cards bonded together using 802.3ad algorithm
with xmit_hash_policy set to layer3+4. On the other side is Cisco 2960
switch. Machine is with two quad core Intel Xeons @2.33GHz.

Here goes a screen snapshot of "top" command. The described behavior
have nothing to do with 13% io-wait. It happens even if it is 0%
io-wait.
http://www.titov.net/misc/top-snap.png

kernel configuration:
http://www.titov.net/misc/config.gz

/proc/interrupts, lspci, dmesg (nothing intresting there), ifconfig,
uname -a:
http://www.titov.net/misc/misc.txt.gz

Is it a Linux bug or some hardware limitation?

Regards,
Anton Titov


             reply	other threads:[~2008-04-15 18:16 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-15 18:06 Anton Titov [this message]
2008-04-15 20:14 ` Bad network performance over 2Gbps Willy Tarreau
2008-04-15 20:40   ` Kok, Auke
2008-04-15 22:36     ` Anton Titov
2008-04-16  4:27       ` Willy Tarreau
2008-04-15 20:15 ` H. Willstrand
2008-04-15 20:34   ` Kok, Auke
2008-04-15 20:59     ` Chris Snook
2008-04-15 21:05       ` Kok, Auke
2008-04-17 10:02       ` Anton Titov
2008-04-17 17:37         ` [PATCH] " Kok, Auke
2008-04-20 12:08           ` Denys Fedoryshchenko
2008-04-21 13:19           ` Pavel Machek
2008-04-21 16:38             ` Kok, Auke
2008-04-21 15:28           ` Ingo Molnar
2008-04-21 16:58             ` Kok, Auke
2008-04-21 18:35               ` Andi Kleen
2008-04-22  5:07           ` Bill Fink

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