Hi, > Currently fdatasync is identical to fsync in ext3,4. > I think fdatasync should skip journal flush in data=ordered and data=writeback mode > when it overwrites to already-instantiated blocks on HDD. > When I_DIRTY_DATASYNC flag is not set, fdatasync should skip journal writeout > because this indicates only atime or/and mtime updates. > > Following patch is the same approach of ext2's fsync code(ext2_sync_file). > > I did a performance test using the sysbench. > > #sysbench --num-threads=128 --max-requests=50000 --test=fileio --file-total-size=128G > --file-test-mode=rndwr --file-fsync-mode=fdatasync run > > The result was: > > -2.6.24 > Operations performed: 0 Read, 50080 Write, 59600 Other = 109680 Total > Read 0b Written 782.5Mb Total transferred 782.5Mb (12.116Mb/sec) > 775.45 Requests/sec executed > > Test execution summary: > total time: 64.5814s > total number of events: 50080 > total time taken by event execution: 3713.9836 > per-request statistics: > min: 0.0000s > avg: 0.0742s > max: 0.9375s > approx. 95 percentile: 0.2901s > > Threads fairness: > events (avg/stddev): 391.2500/23.26 > execution time (avg/stddev): 29.0155/1.99 > > > -2.6.24-patched > Operations performed: 0 Read, 50009 Write, 61596 Other = 111605 Total > Read 0b Written 781.39Mb Total transferred 781.39Mb (16.419Mb/sec) > 1050.83 Requests/sec executed > > Test execution summary: > total time: 47.5900s > total number of events: 50009 > total time taken by event execution: 2934.5768 > per-request statistics: > min: 0.0000s > avg: 0.0587s > max: 0.8938s > approx. 95 percentile: 0.1993s > > Threads fairness: > events (avg/stddev): 390.6953/22.64 > execution time (avg/stddev): 22.9264/1.17 > > > Filesystem I/O throughput was improved. > > Thanks. > > Signed-off-by :Hisashi Hifumi <hifumi.hisashi@xxxxxxxxxxxxx> Yes, the patch looks fine. You can add Acked-by: Jan Kara <jack@xxxxxxx> if you wish. Honza > diff -Nrup linux-2.6.24.org/fs/ext3/fsync.c linux-2.6.24/fs/ext3/fsync.c > --- linux-2.6.24.org/fs/ext3/fsync.c 2008-01-25 07:58:37.000000000 +0900 > +++ linux-2.6.24/fs/ext3/fsync.c 2008-02-04 12:42:42.000000000 +0900 > @@ -72,6 +72,9 @@ int ext3_sync_file(struct file * file, s > goto out; > } > > + if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) > + goto out; > + > /* > * The VFS has written the file data. If the inode is unaltered > * then we need not start a commit. > diff -Nrup linux-2.6.24.org/fs/ext4/fsync.c linux-2.6.24/fs/ext4/fsync.c > --- linux-2.6.24.org/fs/ext4/fsync.c 2008-01-25 07:58:37.000000000 +0900 > +++ linux-2.6.24/fs/ext4/fsync.c 2008-02-04 12:43:37.000000000 +0900 > @@ -72,6 +72,9 @@ int ext4_sync_file(struct file * file, s > goto out; > } > > + if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) > + goto out; > + > /* > * The VFS has written the file data. If the inode is unaltered > * then we need not start a commit. > > - > 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 -- Jan Kara <jack@xxxxxxx> SuSE CR Labs - 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
