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

[Seth Goldberg]

This problem is present, at least, on ZFS.

  --S

On Apr 14, 2011, at 8:55 PM, Vladimir 'φ-coder/phcoder' 
Serbinenko<address@hidden> wrote:

> On 15.04.2011 04:45, Bean wrote:
>> Hi,
>> 
>> I believe this is caused by the read algorithm of grub2. If the file
>> is continuous, grub legacy will read it in one pass, while grub2 will
>> break it up into small blocks, this will slow it down dramatically. I
>> haven't tested efi, but in bios mode, sometimes it takes twice as long
>> for grub2 to read the same file.
>> 
> That's why I asked which fs it is. On an FS like ext2 or fat Both GRUBs
> are limited by the need of rereading indirect blocks or FAT chain (sure
> this can be aleviated by buffering and merging the nodes but neither
> GRUB Legacy nor GRUB2 does it). Currently it makes difference only on
> extent-based filesystems like ext, xfs or btrfs. I don't want to embark
> on adding another code path in grub_disk_read before having enough info
> to confirm this theory yet neither the original reporter nor the others
> answered which FS they conducted experiments on.
> 
> -- 
> Regards
> Vladimir 'φ-coder/phcoder' Serbinenko
> 
> 
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