Gitweb: http://git.kernel.org/linus/bddaafa11a549fff311bcf2e04bbfb5139812cb7
Commit: bddaafa11a549fff311bcf2e04bbfb5139812cb7
Parent: 6447c36209c4268352d55d04d041396ebb8add4a
Author: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
AuthorDate: Sun Mar 29 09:53:38 2009 +0200
Committer: Christoph Hellwig <hch@brick.lst.de>
CommitDate: Sun Mar 29 09:53:38 2009 +0200
xfs: pagecache usage optimization
Hi.
I introduced "is_partially_uptodate" aops for XFS.
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.
#sysbench --num-threads=4 --max-requests=100000 --test=fileio --file-num=1 \
--file-block-size=8K --file-total-size=1G --file-test-mode=rndrw \
--file-fsync-freq=0 --file-rw-ratio=0.5 run
-2.6.29-rc6
Test execution summary:
total time: 123.8645s
total number of events: 100000
total time taken by event execution: 442.4994
per-request statistics:
min: 0.0000s
avg: 0.0044s
max: 0.3387s
approx. 95 percentile: 0.0118s
-2.6.29-rc6-patched
Test execution summary:
total time: 108.0757s
total number of events: 100000
total time taken by event execution: 417.7505
per-request statistics:
min: 0.0000s
avg: 0.0042s
max: 0.3217s
approx. 95 percentile: 0.0118s
arch: ia64
pagesize: 16k
blocksize: 4k
Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Felix Blyakher <felixb@sgi.com>
---
fs/xfs/linux-2.6/xfs_aops.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index de3a198..c13f673 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -1623,4 +1623,5 @@ const struct address_space_operations xfs_address_space_operations = {
.bmap = xfs_vm_bmap,
.direct_IO = xfs_vm_direct_IO,
.migratepage = buffer_migrate_page,
+ .is_partially_uptodate = block_is_partially_uptodate,
};
--
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