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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Changli Gao <xiaosuo@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	Tom Herbert <therbert@google.com>,
	netdev@vger.kernel.org, Ben Hutchings <bhutchings@solarflare.com>
Subject: Re: [PATCH] rps: make distributing packets fairly among all the online CPUs default
Date: Tue, 23 Mar 2010 12:38:26 +0100	[thread overview]
Message-ID: <1269344306.2983.16.camel@edumazet-laptop> (raw)
In-Reply-To: <412e6f7f1003230303l69fc142ey1581fff4c3e749be@mail.gmail.com>

Le mardi 23 mars 2010 à 18:03 +0800, Changli Gao a écrit :

> 
> Ben Hutchings raised this question, but nobody replied with any message.
> 
> I do think distributing packets fairly among all the online CPUs will
> helps most of users. I remember the smp_affinity of IRQ is the
> online_cpu_mask be default.
> 

I know _many_ applications that perform better when all network IRQS are
directed to one CPU only. Single threaded UDP server for example, with
fast answer, or routers, or ...

Many sysadmins tuned their machine to meet this requirement. Installing
2.6.35, if RPS enabled by default will make them unhappy, especially if
CONFIG_SYSFS is not set, since they wont be able to change RPS settings.

If RPS was good for all workloads, activating it would make sense, but
this is not the case.



  reply	other threads:[~2010-03-23 11:38 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-23  6:24 [PATCH] rps: make distributing packets fairly among all the online CPUs default Changli Gao
2010-03-23  7:20 ` Eric Dumazet
2010-03-23  9:56   ` Changli Gao
2010-03-23 11:23     ` Eric Dumazet
2010-03-23 11:27       ` Changli Gao
2010-03-23  7:27 ` Eric Dumazet
2010-03-23 10:03   ` Changli Gao
2010-03-23 11:38     ` Eric Dumazet [this message]
2010-03-23 11:58       ` Changli Gao
2010-03-23 13:06         ` Eric Dumazet
2010-03-23 19:09           ` David Miller
2010-03-23 14:05     ` Andi Kleen

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