Re: Grub2 EFI: Image loading from USB takes too long

[Seth Goldberg]

It's not just USB.  Loading large files via UEFI with GRUB2 takes an extremely 
long time.  One of the things phcoder suggested was changing the cache size, 
which you've done.  Od love to see a larger cache committed to the trunk so 
UEFI platforms can benefit when large files need to be read by GRUB2 (assuming 
no other side effects)!

  --S

On Apr 4, 2011, at 10:33 PM, Aravind Srinivasan <address@hidden> wrote:

> 
> Hi,
> 
> I am trying Grub2 EFI - this is on a custom platform. On 1.99-rc1, compared 
> to 
> Legacy grub, loading image, in particular initrd image from a USB takes a 
> very 
> long.  Our initrd image is about 160M and it is taking about 2 mins to load 
> this 
> image. Turning on "set debug=all" in the grub.cfg file, I see that all the 
> time 
> is being spent in reading the USB. Looking at the source, I think the issue 
> is 
> the value set for GRUB_DISK_CACHE_SIZE in include/grub/disk.h
> Currently this is what it is set to:
> 
> include/grub/disk.h
> <snip>
> /* The size of a disk cache in sector units.  */
> #define GRUB_DISK_CACHE_SIZE   8 
> #define GRUB_DISK_CACHE_BITS   3       
> <snip>
> 
> I tried changing this value to 8192 - and the time it took to load the same 
> image came down to 10 secs ! 
> /* The size of a disk cache in sector units.  */
> #define GRUB_DISK_CACHE_SIZE   8192 
> #define GRUB_DISK_CACHE_BITS   13       
> 
> I am not sure of the reason for setting the cache size to a low value and any 
> possible issues in increasing this size. Appreciate any input on this.
> 
> Thanks,
> -Aravind
> Insert mode
> 
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