[U-Boot] ext2 file system performance

Marek Vasut marex at denx.de
Fri Mar 16 05:42:58 CET 2012


Dear jonsmirl at gmail.com,

> The ext2 file system code is reading the kernel image off from my SD
> card one sector at a time. Of course this takes 61 seconds to get the
> kernel in to memory. Loading the same kernel off from the same SD on
> FAT takes less than a second.
> 
> Nice quick FAT reads...
> 
> reading uImage
> JDS start 7c0 count 1
> JDS start 9d0 count 2
> JDS start 7d0 count 6
> JDS start 1aa0 count 1090
> JDS start 2b30 count e
> JDS start 2b3e count 1
> 
> Ext2 takes about 8,000 single sector reads. File is not fragmented, it
> is the only file on a freshly formatted volume.
> Is there anyway to convince the ext2 code to use larger reads?

It's probably best to dive into the code, I can't answer this out of the top of 
my head, maybe someone else can though.

Best regards,
Marek Vasut


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