2011/06/18 16:19, Andreas Dilger wrote:
I was thinking about this, and am wondering if it makes sense to have an absolute score for fragmentation instead of a relative one? By absolute I mean something like fragments per MB or similar. A bad score might be anything> 1. For files smaller than 1 MB in size it would scale the ratio to the equivalent if the file was 1MB in size (e.g. a 16kB file with 4 fragments would have a score of 256, which is clearly bad). Large files can have a score much less than 1, which is good.
I think fragments per MB is easy to understand. I will fix the library function to "double e2p_get_fragscore(int fd)". To return fragments per MB, it will get the number of extents and the total length of extents except the following special cases: - The extent whose initialize status is different from the next extent - There is a hole between the extent and the next extent - The extent is a tail The output of filefrag would be as follows: # filefrag /mnt/mp1/testfile /mnt/mp1/testfile: 4 extents found, 0.75 fragments/MB Regards, Kazuya Mio -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
