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From: Eric Dumazet <eric.dumazet@gmail.com>
To: jhs@mojatatu.com
Cc: David Miller <davem@davemloft.net>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	netdev@vger.kernel.org
Subject: Re: [PATCH] net_sched: fix dequeuer fairness
Date: Sun, 26 Jun 2011 17:53:50 +0200	[thread overview]
Message-ID: <1309103630.2532.42.camel@edumazet-laptop> (raw)
In-Reply-To: <1309102334.5134.31.camel@mojatatu>

Le dimanche 26 juin 2011 à 11:32 -0400, jamal a écrit :
> On Sun, 2011-06-26 at 17:09 +0200, Eric Dumazet wrote:
> 
> 
> > I would just remove the jiffies break, now we have a 64 packets limit...
> > 
> > if (quota >= work || need_resched()) {
> > 	...
> > }
> 
> Seems reasonable to do. Some stats (on two different machines
> at least with dummy) on a system with low # of processes:
> ~80% of the time - we exit the loop because of packet quota
> ~1% for both need_resched and jiffy
> ~19% simply because there were less than quota packets
> 
> Note: we do use a jiffy check on net_rx_action() but i suspect
> we never ever hit it.

This is because of commit 24f8b2385e03a4f.

Prior to this, we could exit very fast from this function, even after
receiving a single packet.

jiffies break is kind of lazy, IMHO ;)




  reply	other threads:[~2011-06-26 15:53 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-26 14:07 [PATCH] net_sched: fix dequeuer fairness jamal
2011-06-26 14:17 ` jamal
2011-06-26 14:53   ` Ben Hutchings
2011-06-26 15:27     ` jamal
2011-06-26 15:09 ` Eric Dumazet
2011-06-26 15:32   ` jamal
2011-06-26 15:53     ` Eric Dumazet [this message]
2011-06-26 16:13       ` jamal
2011-06-26 16:03     ` jamal
2011-06-26 16:26       ` Eric Dumazet
2011-06-26 16:29         ` jamal
2011-06-26 21:18           ` Ben Hutchings
2011-06-26 16:38         ` jamal
2011-06-26 18:13           ` jamal
2011-06-27  7:15             ` David Miller

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