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NILFS2: Pagecache usage optimization on NILFS2

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Hi,

I introduced "is_partially_uptodate" aops for NILFS2.

A page can have multiple buffers and even if a page is not uptodate, some buffers
can be uptodate on pagesize != blocksize environment.
This aops checks that all buffers which correspond to a part of a file
that we want to read are uptodate. If so, we do not have to issue actual
read IO to HDD even if a page is not uptodate because the portion we
want to read are uptodate.
"block_is_partially_uptodate" function is already used by ext2/3/4.
With the following patch random read/write mixed workloads or random read after
random write workloads can be optimized and we can get performance improvement.

I did a performance test using the sysbench.

1 --file-block-size=8K --file-total-size=2G --file-test-mode=rndrw --file-fsync-freq=0 --fil
e-rw-ratio=1 run

-2.6.30-rc5

Test execution summary:
    total time:                          151.2907s
    total number of events:              200000
    total time taken by event execution: 2409.8387
    per-request statistics:
         min:                            0.0000s
         avg:                            0.0120s
         max:                            0.9306s
         approx.  95 percentile:         0.0439s

Threads fairness:
    events (avg/stddev):           12500.0000/238.52
    execution time (avg/stddev):   150.6149/0.01

-2.6.30-rc5-patched

Test execution summary:
    total time:                          140.8828s
    total number of events:              200000
    total time taken by event execution: 2240.8577
    per-request statistics:
         min:                            0.0000s
         avg:                            0.0112s
         max:                            0.8750s
         approx.  95 percentile:         0.0418s

Threads fairness:
    events (avg/stddev):           12500.0000/218.43
    execution time (avg/stddev):   140.0536/0.01

arch: ia64
pagesize: 16k

Thanks.

Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This commit is contained in:
Hisashi Hifumi 2009-05-13 11:19:40 +09:00 committed by Ryusuke Konishi
parent 7cde31d7d6
commit 258ef67e24
1 changed files with 1 additions and 0 deletions
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1
fs/nilfs2/inode.c
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@ -249,6 +249,7 @@ struct address_space_operations nilfs_aops = {
/* .releasepage = nilfs_releasepage, */ /* .releasepage = nilfs_releasepage, */
.invalidatepage = block_invalidatepage, .invalidatepage = block_invalidatepage,
.direct_IO = nilfs_direct_IO, .direct_IO = nilfs_direct_IO,
.is_partially_uptodate = block_is_partially_uptodate,
}; };
struct inode *nilfs_new_inode(struct inode *dir, int mode) struct inode *nilfs_new_inode(struct inode *dir, int mode)