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List:       grub-devel
Subject:    Re: Slow disk access
From:       Marco Gerards <metgerards () student ! han ! nl>
Date:       2005-02-05 14:07:39
Message-ID: 87sm4bqevo.fsf () marco ! marco-g ! com
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"Yoshinori K. Okuji" <okuji@enbug.org> writes:

> On Friday 04 February 2005 22:11, Marco Gerards wrote:
>> The disk access on GRUB 2 is terribly slow.  At first I thought it
>> was only a problem on the PPC, but it is also showing up in grub-emu
>> and I guess on the PC as well.  You can notice the problem when
>> reading in big files, like a big kernel.  Reading in a 20MB files
>> takes 17 seconds.
>
> I don't see such a problem with grub-emu on PC. I tested the current CVS 
> version. I made a hard disk image with ext2, put a 20MB file on it and 
> run "cat (hd0,0)/foo" with the output of cat disabled (I modified the 
> code). It took about 2 seconds on my laptop. Since my disk is really 
> slow, I think this is normal. I did this test after I "cat" two ISO 
> image files to /dev/null to flush the cache of the hard disk image.

Interesting, I will try this too or see how it differs from my test
code.

> So I guess it is specific to PowerPC.

The grub-emu test was on the PC.

Thanks a lot for testing this.  I guess the problem is even more
complex than I thought at first.

Thanks,
Marco




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