This includes the two patches that we've discussed before. I sent this as a whole just in case you have to patch the code by yourself. :) thanks, liubo On 05/26/2011 04:19 PM, Liu Bo wrote: > I've been working to try to improve the write-ahead log's performance, > and I found that the bottleneck addresses in the checksum items, > especially when we want to make a random write on a large file, e.g a 4G file. > > Then a idea for this suggested by Chris is to use sub transaction ids and just > to log the part of inode that had changed since either the last log commit or > the last transaction commit. And as we also push the sub transid into the btree > blocks, we'll get much faster tree walks. As a result, we abandon the original > brute force approach, which is "to delete all items of the inode in log", > to making sure we get the most uptodate copies of everything, and instead > we manage to "find and merge", i.e. finding extents in the log tree and merging > in the new extents from the file. > > This patchset puts the above idea into code, and although the code is now more > complex, it brings us a great deal of performance improvement. > > Beside the improvement of log, patch 8 fixes a small but critical bug of log code > with sub transaction. > > Here I have some test results to show, I use sysbench to do "random write + fsync". > > === > sysbench --test=fileio --num-threads=1 --file-num=2 --file-block-size=4K --file-total-size=8G --file-test-mode=rndwr --file-io-mode=sync --file-extra-flags= [prepare, run] > === > > Sysbench args: > - Number of threads: 1 > - Extra file open flags: 0 > - 2 files, 4Gb each > - Block size 4Kb > - Number of random requests for random IO: 10000 > - Read/Write ratio for combined random IO test: 1.50 > - Periodic FSYNC enabled, calling fsync() each 100 requests. > - Calling fsync() at the end of test, Enabled. > - Using synchronous I/O mode > - Doing random write test > > Sysbench results: > === > Operations performed: 0 Read, 10000 Write, 200 Other = 10200 Total > Read 0b Written 39.062Mb Total transferred 39.062Mb > === > a) without patch: (*SPEED* : 451.01Kb/sec) > 112.75 Requests/sec executed > > b) with patch: (*SPEED* : 4.3621Mb/sec) > 1116.71 Requests/sec executed > > v1->v2: fix a EEXIST by logged_trans and a mismatch by log root generation > > Liu Bo (11): > Btrfs: introduce sub transaction stuff > Btrfs: update block generation if should_cow_block fails > Btrfs: modify btrfs_drop_extents API > Btrfs: introduce first sub trans > Btrfs: still update inode trans stuff when size remains unchanged > Btrfs: improve log with sub transaction > Btrfs: add checksum check for log > Btrfs: fix a bug of log check > Btrfs: kick off useless code > Btrfs: deal with EEXIST after iput > Btrfs: use the right generation number to read log_root_tree > > fs/btrfs/btrfs_inode.h | 12 ++- > fs/btrfs/ctree.c | 69 +++++++++---- > fs/btrfs/ctree.h | 5 +- > fs/btrfs/disk-io.c | 12 +- > fs/btrfs/extent-tree.c | 10 +- > fs/btrfs/file.c | 22 ++--- > fs/btrfs/inode.c | 33 ++++--- > fs/btrfs/ioctl.c | 6 +- > fs/btrfs/relocation.c | 6 +- > fs/btrfs/transaction.c | 13 ++- > fs/btrfs/transaction.h | 19 +++- > fs/btrfs/tree-defrag.c | 2 +- > fs/btrfs/tree-log.c | 267 +++++++++++++++++++++++++++++++++++------------- > 13 files changed, 330 insertions(+), 146 deletions(-) > > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
