From: Eric Dumazet <eric.dumazet@gmail.com>
To: Alexey Vlasov <renton@renton.name>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>
Subject: Re: Packet time delays on multi-core systems
Date: Thu, 30 Sep 2010 14:46:52 +0200 [thread overview]
Message-ID: <1285850812.2615.432.camel@edumazet-laptop> (raw)
In-Reply-To: <20100930123048.GA4094@beaver.vrungel.ru>
Le jeudi 30 septembre 2010 à 16:30 +0400, Alexey Vlasov a écrit :
> On Wed, Sep 29, 2010 at 11:45:21PM +0200, Eric Dumazet wrote:
> > But if you send SYN packets in the same time, (logged), this might
> > slow
> > down the reception (and answers) of ICMP frames. LOG target can be
> > quite
> > expensive...
>
> Yes, it's clear that some slow down can appear, but 100 ms is too much,
> and this happens at 200 SYN packets in 2 minutes just as in my example.
> On old servers where some tx/rx are missing in NIC card I don't see
> such a situation even at more then 1000 SYN-packets per sec.
Because all cpus were servicing interrupts, which was good for your
needs. Things apparently changed with 2.6.32.
You have a multiqueue NIC, but using a single CPU to handle the
workload.
>
> > Is using other rules gives same problem ?
> >
> > iptables -A OUTPUT -p tcp -m tcp --dport 80 --tcp-flags
>
> No, only LOG gives such a scheme.
>
prev parent reply other threads:[~2010-09-30 12:46 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20100929191851.GC86786@beaver.vrungel.ru>
2010-09-29 21:45 ` Packet time delays on multi-core systems Eric Dumazet
2010-09-30 6:24 ` Alexey Vlasov
2010-09-30 6:33 ` Eric Dumazet
2010-09-30 12:23 ` Alexey Vlasov
2010-09-30 12:44 ` Eric Dumazet
2010-09-30 17:37 ` Alexey Vlasov
2010-09-30 18:03 ` Eric Dumazet
2010-09-30 18:15 ` Alexey Vlasov
2010-09-30 18:52 ` Eric Dumazet
2010-10-01 10:16 ` Alexey Vlasov
2010-10-01 12:59 ` Eric Dumazet
2010-10-01 14:18 ` Alexey Vlasov
2010-10-01 15:27 ` Eric Dumazet
2010-10-01 18:54 ` Jeff Kirsher
2010-09-30 12:30 ` Alexey Vlasov
2010-09-30 12:46 ` Eric Dumazet [this message]
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