linux and initrd load very slowly on UEFI system
Bug #944347 reported by
Kamal Mostafa
This bug affects 2 people
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
grub2 (Ubuntu) |
Fix Released
|
Critical
|
Adam Conrad |
Bug Description
On a Intel Tunnel Mountain system, grub2 loads from disk very slowly when booting with UEFI: about 53 seconds to execute a pair of "linux" and "initrd" commands.
Expected behavior:
Load time for linux and initrd should be on order of 1 second.
Problem observed with:
grub2 (oneiric) 1.99-12ubuntu5
grub2 (precise) 1.99-14ubuntu2
Intel Tunnel Mountain UEFI BIOS version SDV.TM.B8 or SDV.TM.B9
Related branches
Changed in grub2 (Ubuntu): | |
assignee: | Kamal Mostafa (kamalmostafa) → nobody |
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The performance problem appears to be due to overhead of the individual disk read calls...
grub2's disk I/O layer buffers 8 disk sectors per read, hard-coded in include/grub/disk.h as GRUB_DISK_ CACHE_SIZE.
Increasing GRUB_DISK_ CACHE_SIZE to 1024 (patch attached) dramatically improves the load performance for my Intel Tunnel Mountain system booting with UEFI: total load time for linux and initrd is reduced from about 53 seconds to about 1 second.