On Tue, Apr 5, 2011 at 12:02, Seth Goldberg <seth.goldb...@oracle.com> wrote: > 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 <aravind_s_...@yahoo.com> > 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 >> >> _______________________________________________ >> Grub-devel mailing list >> Grub-devel@gnu.org >> http://lists.gnu.org/mailman/listinfo/grub-devel > > _______________________________________________ > Grub-devel mailing list > Grub-devel@gnu.org > http://lists.gnu.org/mailman/listinfo/grub-devel >
I can confirm that grub2 x86_64-efi is very slow in loading initramfs files. I did my testing in VirtualBox 4.0.4 (VBox patched OVMF, quite old compared to updated OVMF) using an iso mounted in a virtual SATA AHCI CD drive and 1 GiB RAM alloted to the virtual machine. Intel VT extension was enabled. In a crude benchmarking using s top watch, the time between selection of menuentry to seeing the kernel boot messages is approx 4 minutes (236 seconds) measured using a stop watch. I have not yet tested with an updated ovmf in qemu or in duet. I guess accessing from HDDs is faster in UEFI systems. Its the CDs and USB which seem to take a lot of time. The kernel loaded by grub2 during the test and the initramfs can be downloaded from ftp://ftp.archlinux.org/iso/archboot/2011.02/boot/vm64 - kernel (lzma compressed) ftp://ftp.archlinux.org/iso/archboot/2011.02/boot/initrd64.img - initramfs (lzma -9 compressed cpio archive). Regards. Keshav _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org http://lists.gnu.org/mailman/listinfo/grub-devel
