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From: Rick Jones <rick.jones2@hp.com>
To: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: netdev@vger.kernel.org
Subject: Re: [RFC PATCH] net: add additional lock to qdisc to increase	enqueue/dequeue fairness
Date: Tue, 23 Mar 2010 13:40:00 -0700	[thread overview]
Message-ID: <4BA92720.5090403@hp.com> (raw)
In-Reply-To: <20100323202553.21598.10754.stgit@gitlad.jf.intel.com>

Alexander Duyck wrote:
> The qdisc layer shows a significant issue when you start transmitting from
> multiple CPUs.  The issue is that the transmit rate drops significantly, and I
> believe it is due to the fact that the spinlock is shared between the 1
> dequeue, and n-1 enqueue cpu threads.  In order to improve this situation I am
> adding one additional lock which will need to be obtained during the enqueue
> portion of the path.  This essentially allows sch_direct_xmit to jump to
> near the head of the line when attempting to obtain the lock after
> completing a transmit.
> 
> Running the script below I saw an increase from 200K packets per second to
> 1.07M packets per second as a result of this patch.
> 
> for j in `seq 0 15`; do
> 	for i in `seq 0 7`; do
> 		netperf -H <ip> -t UDP_STREAM -l 600 -N -T $i -- -m 6 &
> 	done
> done


Wow - someone is using the no control connection mode in netperf :)  Or were you 
actually trying to get the test-specific -N option to control whether or not 
netperf "connects" the UDP socket?

rick jones

  parent reply	other threads:[~2010-03-23 20:40 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-23 20:25 [RFC PATCH] net: add additional lock to qdisc to increase enqueue/dequeue fairness Alexander Duyck
2010-03-23 20:31 ` David Miller
2010-03-24  2:12   ` Andi Kleen
2010-03-23 20:40 ` Rick Jones [this message]
2010-03-23 20:54 ` Eric Dumazet
2010-03-23 21:18   ` Eric Dumazet
2010-03-23 21:45   ` David Miller
2010-03-23 22:08     ` Duyck, Alexander H
2010-03-24  2:58       ` David Miller
2010-03-24  5:42         ` Eric Dumazet
2010-03-24  6:10           ` David Miller
2010-03-23 22:13     ` Eric Dumazet
2010-05-21 15:43       ` Stephen Hemminger
2010-05-21 16:44         ` Eric Dumazet
2010-05-21 17:38           ` Stephen Hemminger
2010-05-21 17:40           ` Eric Dumazet
2010-06-02  9:48             ` Eric Dumazet
2010-06-02  9:49             ` [PATCH 1/2 net-next-2.6] net: Define accessors to manipulate QDISC_STATE_RUNNING Eric Dumazet
2010-06-02 10:24               ` David Miller
2010-06-02  9:50             ` [PATCH 2/2 net-next-2.6] net: QDISC_STATE_RUNNING dont need atomic bit ops Eric Dumazet
2010-06-02 10:25               ` David Miller
2010-03-24 14:24 ` [RFC PATCH] net: add additional lock to qdisc to increase enqueue/dequeue fairness Eric Dumazet
2010-05-21 15:08 ` [PATCH] net: add additional lock to qdisc to increase throughput Eric Dumazet
2010-05-21 20:04   ` Duyck, Alexander H
2010-06-02 12:10     ` David Miller
2010-06-02 14:52       ` Eric Dumazet

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