lkml.org 
[lkml]   [2007]   [Nov]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] ext4: dir inode reservation V3
    Thanks for the feedback :-)

    Alex Tomas wrote:
    > hmm. so you trade 265% degradation of creation for 40% improvement of
    > unlink?
    >
    265% degradation is only for creating 50000 empty directories. This is not a common case.
    There are 13% improvement on create 15 files in each directories. Total time on creating these
    directories and files are 25m6s VS. 24m86s, indeed, dir inode reservation is a little faster.

    Maybe most of the people will not create dozens of empty directories in their applications,
    therefore IMHO the 265% degradation is acceptable.

    If user really need to create so many empty directories, they also can mount the file system without
    dir inode reservation to get better performance.

    > thanks, Alex
    >
    > Coly Li wrote:
    >> normal ext4 ext4 with dir inode reservation
    >> mount options: -o data=writeback -o
    >> data=writeback,dir_ireserve=low
    >> Create dirs: real 0m49.101s real 2m59.703s
    >> Create files: real 24m17.962s real 21m8.161s
    >> Unlink all: real 24m43.788s real 17m29.862s
    >> Creating dirs with dir inode reservation is slower than normal ext4 as
    >> predicted, because allocating
    >> directory inodes in non-linear order will cause extra hard disk
    >> seeking and block I/O. Creating
    >> files with dir inode reservation is 13% faster than normal ext4.
    >> Unlink all the directories and
    >> files is 29.2% faster as expected.
    >> When number of directories is increased, the performance improvement
    >> will be more considerable. More
    >> benchmark result will be posted here if necessary, because I need more
    >> time to run more test cases.
    >

    --
    Coly Li
    SuSE PRC Labs
    -
    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/

    \
     
     \ /
      Last update: 2007-11-13 17:23    [W:6.956 / U:0.032 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site