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From: Matthew Wilcox <matthew@wil.cx>
To: "Ma, Chinang" <chinang.ma@intel.com>
Cc: Rick Jones <rick.jones2@hp.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Jeff Garzik <jeff@garzik.org>,
	"andi@firstfloor.org" <andi@firstfloor.org>,
	"arjan@infradead.org" <arjan@infradead.org>,
	"jens.axboe@oracle.com" <jens.axboe@oracle.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Styner, Douglas W" <douglas.w.styner@intel.com>,
	"Prickett, Terry O" <terry.o.prickett@intel.com>,
	"Wilcox, Matthew R" <matthew.r.wilcox@intel.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"Brandeburg, Jesse" <jesse.brandeburg@intel.com>
Subject: Re: >10% performance degradation since 2.6.18
Date: Mon, 6 Jul 2009 12:53:53 -0600	[thread overview]
Message-ID: <20090706185353.GY5480@parisc-linux.org> (raw)
In-Reply-To: <BC02C49EEB98354DBA7F5DD76F2A9E800357E11D67@azsmsx501.amr.corp.intel.com>

On Mon, Jul 06, 2009 at 11:48:47AM -0700, Ma, Chinang wrote:
> On the distributing interrupt load subject.  Can we do the same thing with the IOC interrupts. We have 4 LSI 3801, The number of i/o interrupt is huge on 4 of the cpus. Is there a way to divide the IOC irq number so we can spread out the i/o interrupt to more cpu?

I think the LSI 3801 only has one interrupt per ioc, but they could
perhaps be better spread-out.  Right now, they're delivering interrupts
to CPUs 2, 3, 4 and 5.  Possibly spreading them out to CPUs 2, 6, 10
and 14 would help.  Or maybe it would hurt ...

(nb: the ioc interrupts are similarly tied to CPUs 2, 3, 4 and 5 with
2.6.18, so this isn't a likely cause of/solution to the regression,
it may just be a path to better numbers).

-- 
Matthew Wilcox				Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."

      reply	other threads:[~2009-07-06 18:53 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20090703025607.GK5480@parisc-linux.org>
     [not found] ` <87skhdaaub.fsf@basil.nowhere.org>
     [not found]   ` <20090703185414.GP23611@kernel.dk>
     [not found]     ` <20090703191321.GO5480@parisc-linux.org>
     [not found]       ` <20090703192235.GV23611@kernel.dk>
     [not found]         ` <20090703194557.GQ5480@parisc-linux.org>
     [not found]           ` <20090703195458.GK2041@one.firstfloor.org>
     [not found]             ` <20090703130421.646fe5cb@infradead.org>
     [not found]               ` <20090703233505.GL2041@one.firstfloor.org>
     [not found]                 ` <20090703230408.4433ee39@infradead.org>
     [not found]                   ` <20090704084430.GO2041@one.firstfloor.org>
2009-07-04  9:19                     ` >10% performance degradation since 2.6.18 Jeff Garzik
2009-07-05  4:01                       ` Herbert Xu
2009-07-05 13:09                         ` Matthew Wilcox
2009-07-05 16:11                           ` Herbert Xu
2009-07-06  8:38                           ` Andi Kleen
2009-07-05 20:44                         ` Jeff Garzik
2009-07-06  1:19                           ` Herbert Xu
2009-07-06  8:45                           ` Andi Kleen
2009-07-06 17:00                         ` Rick Jones
2009-07-06 17:36                           ` Ma, Chinang
2009-07-06 17:42                             ` Matthew Wilcox
2009-07-06 17:57                               ` Ma, Chinang
2009-07-06 18:05                                 ` Matthew Wilcox
2009-07-06 18:48                                   ` Ma, Chinang
2009-07-06 18:53                                     ` Matthew Wilcox [this message]

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