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Date: Wed, 27 Dec 2000 06:38:10 +0100
From: Jens Axboe <axboe@suse.de>
To: David Mansfield <lkml@dm.ultramaster.com>
Cc: lkml <linux-kernel@vger.kernel.org>
Subject: Re: cdrom changes in test13-pre2 slow down cdrom access by 70%
Message-ID: <20001227063810.E5981@suse.de>
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On Tue, Dec 26 2000, David Mansfield wrote:
> > > > The cdrom changes that went into test13-pre2 really kill the performance
> > > > of my cdrom.  I'm using cdparanoia to read audio data, and it normally
> 
> ... cut ...
> 
> > Anyway, do you think a 'try to allocate 8, if that fails, try to
> > allocate 1' solution would be a simple compromise?  That should be easy
> > to do, based on the above code (if kmalloc returns NULL && frames > 1,
> > frames = 1, retry...).
> > 
> 
> Jens, 
> 
> Here's a version of the above idea, ontop of the patch you sent.  It's
> cut and pasted, but I don't think it's whitespace mangled...  I haven't
> actually run with this patch, but it does compile :-)

In principle it looks ok, but after some time we are bound to fail 8
frame allocations anyway and this patch won't help. For the modular
case, preallocation of a bigger chunk at init time is no good either.
Builtin would be fine of course. This almost screams sg to me :-)

-- 
* Jens Axboe <axboe@suse.de>
* SuSE Labs
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