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authorHisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>2009-03-29 09:53:38 +0200
committerChristoph Hellwig <hch@brick.lst.de>2009-03-29 09:53:38 +0200
commitbddaafa11a549fff311bcf2e04bbfb5139812cb7 (patch)
tree88bbe15cf5022c291f003b58bb6659e285cdda25 /fs/xfs/xfs_iomap.h
parent6447c36209c4268352d55d04d041396ebb8add4a (diff)
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>
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