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From: Benny Amorsen <benny+usenet@amorsen.dk>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Changli Gao <xiaosuo@gmail.com>,
	zhigang gong <zhigang.gong@gmail.com>,
	netdev@vger.kernel.org
Subject: Re: Strange packet drops with heavy firewalling
Date: Thu, 15 Apr 2010 15:23:50 +0200	[thread overview]
Message-ID: <m3633szw61.fsf@ursa.amorsen.dk> (raw)
In-Reply-To: <m3hbnfzsye.fsf@ursa.amorsen.dk> (Benny Amorsen's message of "Tue, 13 Apr 2010 09:56:25 +0200")

Benny Amorsen <benny+usenet@amorsen.dk> writes:

> I'll keep monitoring the server, and if it starts dropping packets again
> or load increases I'll check whether irqbalanced does the right thing,
> and if not I'll implement your suggestion.

It did start dropping packets (although very few, a few packets dropped
at once perhaps every ten minutes). Irqbalanced didn't move the
interrupts.

Doing

echo 01 >/proc/irq/99/smp_affinity
echo 02 >/proc/irq/100/smp_affinity
echo 04 >/proc/irq/101/smp_affinity

and so on like Erik Dumazet suggested seems to have helped, but not
entirely solved the problem.

The problem now manifests itself this way in ethtool -S:
     rx_no_buffer_count: 270
     rx_queue_drop_packet_count: 270

I can't be sure that I'm not just getting hit by a 1Gbps traffic spike,
of course, but it is a bit strange that a machine which can do 200Mbps
at 92% idle can't handle subsecond peaks close to 1Gbps...

I wish ifstat could report errors so I could see what the traffic rate
was when the problem occurred...


/Benny

  reply	other threads:[~2010-04-15 13:24 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-09  9:56 Strange packet drops with heavy firewalling Benny Amorsen
2010-04-09 11:47 ` Eric Dumazet
2010-04-09 12:33   ` Benny Amorsen
2010-04-09 13:29     ` Eric Dumazet
2010-04-12  6:20       ` Benny Amorsen
     [not found] ` <q2v40c9f5b21004120116p766df82dj88c6af4e4cad55f@mail.gmail.com>
2010-04-12 14:44   ` Benny Lyne Amorsen
     [not found]     ` <p2x40c9f5b21004120833jd7a749cak6ea69cebd28f8352@mail.gmail.com>
2010-04-12 17:06       ` Benny Amorsen
2010-04-12 23:18         ` Changli Gao
2010-04-13  5:56           ` Eric Dumazet
2010-04-13  7:56             ` Benny Amorsen
2010-04-15 13:23               ` Benny Amorsen [this message]
2010-04-15 13:42                 ` Eric Dumazet
2010-04-13 12:33           ` Paweł Staszewski
2010-04-13 12:53             ` Eric Dumazet
2010-04-13 13:39               ` Paweł Staszewski

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