From: Mike Hommey <mh@glandium.org>
Date: Tue, 26 Jan 2010 17:19:00 GMT
Subject: Re: [PATCH v4] Threaded grep
Message-ID: <20100126171900.GA14092@glandium.org>
In-Reply-To: <alpine.LFD.2.00.1001260846330.3574@localhost.localdomain>

On Tue, Jan 26, 2010 at 08:56:50AM -0800, Linus Torvalds wrote:
<snip>
> although it is worth noting that that machine has an Intel SSD, which is 
> why it gets sped up so much by parallel IO (there's no seek penalty, and 
> it is able to read multiple channels in parallel, so this gives much 
> better IO patterns for it - with rotational media the numbers might be 
> very different).

For rotational disks, using FIEMAP to get the position of the files on
disk to reorder how we read them could help.

Mike