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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: Andrew Morton <akpm@osdl.org>, Linus Torvalds <torvalds@osdl.org>,
	Linux Kernel list <linux-kernel@vger.kernel.org>,
	list linux-ide <linux-ide@vger.kernel.org>
Subject: Re: page fault scalability patch V12 [0/7]: Overview and performance tests
Date: Thu, 02 Dec 2004 18:05:48 +1100	[thread overview]
Message-ID: <1101971149.5593.64.camel@gaston> (raw)
In-Reply-To: <41AEBD95.7030804@pobox.com>

On Thu, 2004-12-02 at 02:00 -0500, Jeff Garzik wrote:

> 
> 2.6.9:
> 	bitbang ATA taskfile registers
> 	queue_work()
> 	workqueue thread bitbangs ATA data register (read id page)
> 
> So I wonder if <something> doesn't like CPU 0 sending I/O traffic to the 
> on-board SATA PCI device, then immediately after that, CPU 1 sending I/O 
> traffic.
> 
> Anyway, back to debugging...  :)

They may not end up in order if they are stores (the stores to the
taskfile may be out of order vs; the loads/stores to/from the data
register) unless you have a spinlock protecting both or a full sync (on
ppc), but then, I don't know the ordering things on x86_64. This could
certainly be a problem on ppc & ppc64 too.

Ben.



  reply	other threads:[~2004-12-02  7:06 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Pine.LNX.4.44.0411221457240.2970-100000@localhost.localdomain>
     [not found] ` <Pine.LNX.4.58.0411221343410.22895@schroedinger.engr.sgi.com>
     [not found]   ` <Pine.LNX.4.58.0411221419440.20993@ppc970.osdl.org>
     [not found]     ` <Pine.LNX.4.58.0411221424580.22895@schroedinger.engr.sgi.com>
     [not found]       ` <Pine.LNX.4.58.0411221429050.20993@ppc970.osdl.org>
     [not found]         ` <Pine.LNX.4.58.0412011539170.5721@schroedinger.engr.sgi.com>
     [not found]           ` <Pine.LNX.4.58.0412011608500.22796@ppc970.osdl.org>
     [not found]             ` <41AEB44D.2040805@pobox.com>
     [not found]               ` <20041201223441.3820fbc0.akpm@osdl.org>
2004-12-02  7:00                 ` page fault scalability patch V12 [0/7]: Overview and performance tests Jeff Garzik
2004-12-02  7:05                   ` Benjamin Herrenschmidt [this message]
2004-12-02  7:11                     ` Jeff Garzik
2004-12-02 11:16                       ` Benjamin Herrenschmidt
2004-12-02 14:30                   ` Andy Warner
2005-01-06 23:40                     ` Jeff Garzik

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