Re: [PATCH] File readahead buffering

[Bean]

On Wed, Jul 23, 2008 at 10:56 PM, Colin D Bennett <address@hidden> wrote:
> On Wed, 23 Jul 2008 07:33:32 -0700
> Colin D Bennett <address@hidden> wrote:
>
>> On Wed, 23 Jul 2008 10:05:36 +0800
>> Bean <address@hidden> wrote:
>>
>> > On Wed, Jul 23, 2008 at 3:06 AM, Colin D Bennett <address@hidden>
>> > wrote:
>> > > On Tue, 22 Jul 2008 14:48:31 -0400
>> > > Pavel Roskin <address@hidden> wrote:
>> > >
>> > >> On Tue, 2008-07-22 at 08:43 -0700, Colin D Bennett wrote:
>> > >> > This patch speeds up loading a TGA image on my test system from
>> > >> > 29 seconds to approximately 1 second.
>> > >> >
>> > >> > I noticed that on my 1 GHz test system running from an IDE
>> > >> > CompactFlash drive, loading a certain TGA image in GRUB takes
>> > >> > about 29 seconds.
>> > >>
>> > >> I'm sorry for straying from your point, but maybe we should drop
>> > >> TGA support.  It was the first image format for GRUB to support,
>> > >> but now PNG is supported, and it should be better in all aspects.
>> > >
>> > > I agree that TGA is not, in general, a great choice for an image
>> > > format (unless it is faster to load a large background image -- a
>> > > 1024x768 RGB PNG file may take more time to decompress than a TGA
>> > > image would take to load -- although perhaps an uncompressed PNG
>> > > file would be comparable in speed to load).  However, I have not
>> > > been able to load any PNG images that I have tried to use.
>> > > Something about the chunk type not being supported.
>> > >
>> >
>> > Hi,
>> >
>> > Please upload the png file that cause problem.
>> >
>> > Also note that png use DEFLATE compression. I write a decoder in
>> > png, which may be a little slow. Perhaps I can import the decoder
>> > from zlib, if copyright allows.
>>
>> Ok, after some more testing, I have found that if I create PNG images
>> with ImageMagick or The GIMP, they work.  However, I have an image
>> that I was trying to use as a GRUB background which is from a MythTV
>> theme called Titivillus.  The PNG file from the MythTV theme doesn't
>> load in GRUB.  I get the message "error: png: block type fixed not
>> supported".
>
> Oops!  After more testing, I have found PNG images that I saved in The
> GIMP which also refuse to load due to the "block type fixed not
> supported" error.  One ZIP file [1] contains images that all fail to
> load in GRUB with that error, and the other [2] contains similar images
> that load just fine.
>
> [1] gibibit.com/upload/grub-png-bad.zip
> [2] gibibit.com/upload/grub-png-good.zip

Hi,

This patch should fix the problem.

-- 
Bean

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