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Improve odirect-write performance for block-device.

majianpeng linux-fsdevel linux-raid 1 version In review

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  1. v1 Latest2 patches 13 repliesIn review

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#Subject and filesSizeRepliesApplied
1/2fs/block-dev.c:fix performance regression in O_DIRECT writes to md block devices.fs/block_dev.c+6 -12 replies
2/2raid5: For write performance, remove REQ_SYNC when write was odirect.drivers/md/raid5.c+3 -07 replies

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Cover letter [PATCH 0/2] Improve odirect-write performance for block-device.

Create a raid5 using four disk and the chunksize is 512K.
Test command is: dd if=/dev/zero of=/dev/md0 bs=1536K count=90000 oflag=direct

In RHEL6(kernel 2.6.32):speed about 240MB/s
In 3.5.0-rc5:speed about 77MB/S
Add two patch in 3.5.0-rc5, speed about 200MB/S.

So the performance of odirect-wrirte for block-deivce was obvious reduced. PATCH 1/2: Add blk_plug function for odirect-write block-device PATCH 2/2: Remove REQ_SYNC for odirect-write in raid456.

PATCH 2/2 maybe not correct because it alse for odirect-write for regular file. Jianpeng Ma (2):
fs/block-dev.c:fix performance regression in O_DIRECT writes to
md block devices.
raid5: For write performance, remove REQ_SYNC when write was odirect.

 drivers/md/raid5.c |    3 +++
 fs/block_dev.c     |    7 ++++++-
 2 files changed, 9 insertions(+), 1 deletions(-)
Signature · 1 line
1.7.5.4