Messages in this thread |  | | | Date | Tue, 27 Jan 2004 20:13:54 +0100 | | From | Bart Samwel <> | | Subject | Re: Request: I/O request recording |
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Andrew Morton wrote: > You could certainly do that. Given disk block #N you need to search all > files on the disk asking "who owns this block". The FIBMAP ioctl can be > used on most filesystems (ext2, ext3, others..) to find out which blocks a > file is using. See bmap.c in > > http://www.zip.com.au/~akpm/linux/patches/stuff/ext3-tools.tar.gz > > Unfortunately you cannot determine a directory's blocks in this way. > Ext3's directories live in the /dev/hda1 pagecache anyway. ext2's > directories each have their own pagecache.
OK, I've written something that does this (but only correctly for ext3). I've put it here:
http://www.xs4all.nl/~bsamwel/bootup_prefetch.tar.gz
I haven't had the opportunity to do good measurements, so I don't really know if it even increases performance. If anyone feels like benchmarking this, I'd be very happy to hear from you. I don't really expect performance increases, as the bootup scripts seem to have enough processing to do to keep the system busy even without disk I/O. I wonder if it might make a difference on a faster processor though, my system's kind of sluggish by today's standards.
-- Bart - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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