On 06/30/2011 03:36 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: > This is also available in git://repo.or.cz/linux-btrfs-devel.git sub-trans thanks, liubo > in my sysbench "write + fsync" test: > > 451.01Kb/sec -> 4.3621Mb/sec > > Also, I've run the "synctest", and it works well with both directory and file. > > v1->v2, rebase. > v2->v3, thanks to Chris, we worked together to solve 2 bugs, and after that it > worked as expected. > v3->v4, thanks to Josef, we simplify several codes. > > Liu Bo (12): > 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: use the right generation number to read log_root_tree > Btrfs: do not iput inode when inode is still in log > Revert "Btrfs: do not flush csum items of unchanged file data during > treelog" > > 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 | 39 ++++++--- > 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 | 225 ++++++++++++++++++++++++++++++++---------------- > 13 files changed, 293 insertions(+), 147 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 > -- 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
