In ocfs2, fdatasync and fsync are identical.
I think fdatasync should skip committing transaction when
inode->i_state is set just I_DIRTY_SYNC and this indicates
only atime or/and mtime updates.
Following patch improves fdatasync throughput.
#sysbench --num-threads=16 --max-requests=300000 --test=fileio
--file-block-size=4K --file-total-size=16G --file-test-mode=rndwr
--file-fsync-mode=fdatasync run
Results:
-2.6.30-rc8
Test execution summary:
total time: 107.1445s
total number of events: 119559
total time taken by event execution: 116.1050
per-request statistics:
min: 0.0000s
avg: 0.0010s
max: 0.1220s
approx. 95 percentile: 0.0016s
Threads fairness:
events (avg/stddev): 7472.4375/303.60
execution time (avg/stddev): 7.2566/0.64
-2.6.30-rc8-patched
Test execution summary:
total time: 86.8529s
total number of events: 300016
total time taken by event execution: 24.3077
per-request statistics:
min: 0.0000s
avg: 0.0001s
max: 0.0336s
approx. 95 percentile: 0.0001s
Threads fairness:
events (avg/stddev): 18751.0000/718.75
execution time (avg/stddev): 1.5192/0.05
Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Acked-by: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
e04cc15f52