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From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>, Chris Friesen <cfriesen@nortel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	David Miller <davem@davemloft.net>,
	linuxppc-dev@ozlabs.org, paulus@samba.org,
	netdev@vger.kernel.org
Subject: Re: question about softirqs
Date: Tue, 12 May 2009 08:20:51 -0400 (EDT)	[thread overview]
Message-ID: <alpine.DEB.2.00.0905120818290.13234@gandalf.stny.rr.com> (raw)
In-Reply-To: <1242120761.11251.324.camel@twins>



On Tue, 12 May 2009, Peter Zijlstra wrote:

> On Tue, 2009-05-12 at 11:23 +0200, Ingo Molnar wrote:
> > 
> > Yeah, that would be "nice". A single IRQ thread plus the process 
> > context(s) doing networking might perform well.
> > 
> > Multiple IRQ threads (softirq and hardirq threads mixed) i'm not so 
> > sure about - it's extra context-switching cost.
> 
> Sure, that was implied by the getting rid of softirqs ;-), on -rt we
> currently suffer this hardirq/softirq thread ping-pong, it sucks.

I'm going to be playing around with bypassing the net-rx/tx with my 
network drivers. I'm going to add threaded irqs for my network cards and 
have the driver threads do the work to get through the tcp/ip stack.

I'll still keep the softirqs for other cards, but I want to see how fast 
it speeds things up if I have the driver thread do it.

-- Steve


WARNING: multiple messages have this Message-ID (diff)
From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: netdev@vger.kernel.org, David Miller <davem@davemloft.net>,
	linuxppc-dev@ozlabs.org, paulus@samba.org,
	Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: question about softirqs
Date: Tue, 12 May 2009 08:20:51 -0400 (EDT)	[thread overview]
Message-ID: <alpine.DEB.2.00.0905120818290.13234@gandalf.stny.rr.com> (raw)
In-Reply-To: <1242120761.11251.324.camel@twins>



On Tue, 12 May 2009, Peter Zijlstra wrote:

> On Tue, 2009-05-12 at 11:23 +0200, Ingo Molnar wrote:
> > 
> > Yeah, that would be "nice". A single IRQ thread plus the process 
> > context(s) doing networking might perform well.
> > 
> > Multiple IRQ threads (softirq and hardirq threads mixed) i'm not so 
> > sure about - it's extra context-switching cost.
> 
> Sure, that was implied by the getting rid of softirqs ;-), on -rt we
> currently suffer this hardirq/softirq thread ping-pong, it sucks.

I'm going to be playing around with bypassing the net-rx/tx with my 
network drivers. I'm going to add threaded irqs for my network cards and 
have the driver threads do the work to get through the tcp/ip stack.

I'll still keep the softirqs for other cards, but I want to see how fast 
it speeds things up if I have the driver thread do it.

-- Steve

  reply	other threads:[~2009-05-12 12:20 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-08 22:51 question about softirqs Chris Friesen
2009-05-08 23:05 ` David Miller
2009-05-08 23:34 ` Paul Mackerras
2009-05-08 23:53   ` David Miller
2009-05-09  2:52     ` Benjamin Herrenschmidt
2009-05-09  3:31     ` Paul Mackerras
2009-05-09  6:48       ` David Miller
2009-05-11 18:25         ` Chris Friesen
2009-05-11 23:24           ` David Miller
2009-05-12  0:43             ` Chris Friesen
2009-05-12  8:12               ` Ingo Molnar
2009-05-12  8:12                 ` Ingo Molnar
2009-05-12  9:12                 ` Peter Zijlstra
2009-05-12  9:23                   ` Ingo Molnar
2009-05-12  9:32                     ` Peter Zijlstra
2009-05-12 12:20                       ` Steven Rostedt [this message]
2009-05-12 12:20                         ` Steven Rostedt
2009-05-13  4:45                         ` David Miller
2009-05-13  4:44                     ` David Miller
2009-05-13  4:44                       ` David Miller
2009-05-13  5:15                       ` Paul Mackerras
2009-05-13  5:15                         ` Paul Mackerras
2009-05-13  5:28                         ` David Miller
2009-05-13  5:28                           ` David Miller
2009-05-13  5:55                   ` Evgeniy Polyakov
2009-05-13  5:55                     ` Evgeniy Polyakov
2009-05-12 15:18                 ` Chris Friesen
2009-05-12 15:18                   ` Chris Friesen
2009-05-13  8:34                   ` Andi Kleen
2009-05-13  8:34                     ` Andi Kleen
2009-05-13 13:23                     ` Chris Friesen
2009-05-13 14:15                       ` Andi Kleen
2009-05-13 14:15                         ` Andi Kleen
2009-05-13 14:17                         ` Thomas Gleixner
2009-05-13 14:17                           ` Thomas Gleixner
2009-05-13 14:24                           ` Andi Kleen
2009-05-13 14:24                             ` Andi Kleen
2009-05-13 14:54                             ` Eric Dumazet
2009-05-13 14:54                               ` Eric Dumazet
2009-05-13 15:02                               ` Andi Kleen
2009-05-13 15:02                                 ` Andi Kleen
2009-05-13 15:05                             ` Chris Friesen
2009-05-13 15:54                               ` Thomas Gleixner
2009-05-13 15:54                                 ` Thomas Gleixner
2009-05-13 16:10                                 ` Chris Friesen
2009-05-13 17:01                               ` Andi Kleen
2009-05-13 19:04                                 ` Chris Friesen
2009-05-13 19:04                                   ` Chris Friesen
2009-05-13 19:13                                   ` Andi Kleen
2009-05-13 19:13                                     ` Andi Kleen
2009-05-13 19:44                                     ` Chris Friesen
2009-05-13 19:53                                       ` Andi Kleen
2009-05-13 19:53                                         ` Andi Kleen
2009-05-13 20:55                                         ` Thomas Gleixner
2009-05-13 20:55                                           ` Thomas Gleixner
2009-05-11 23:34           ` Paul Mackerras
2009-05-09  0:28   ` Chris Friesen

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