1. 17 Oct, 2013 1 commit
    • Ming Lei's avatar
      ext4: fix performance regression in ext4_writepages · aeac589a
      Ming Lei authored
      Commit 4e7ea81d(ext4: restructure writeback path) introduces another
      performance regression on random write:
      
      - one more page may be added to ext4 extent in
        mpage_prepare_extent_to_map, and will be submitted for I/O so
        nr_to_write will become -1 before 'done' is set
      
      - the worse thing is that dirty pages may still be retrieved from page
        cache after nr_to_write becomes negative, so lots of small chunks
        can be submitted to block device when page writeback is catching up
        with write path, and performance is hurted.
      
      On one arm A15 board with sata 3.0 SSD(CPU: 1.5GHz dura core, RAM:
      2GB, SATA controller: 3.0Gbps), this patch can improve below test's
      result from 157MB/sec to 174MB/sec(>10%):
      
      	dd if=/dev/zero of=./z.img bs=8K count=512K
      
      The above test is actually prototype of block write in bonnie++
      utility.
      
      This patch makes sure no more pages than nr_to_write can be added to
      extent for mapping, so that nr_to_write won't become negative.
      
      Cc: linux-ext4@vger.kernel.org
      Acked-by: default avatarJan Kara <jack@suse.cz>
      Signed-off-by: default avatarMing Lei <ming.lei@canonical.com>
      Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
      aeac589a
  2. 16 Oct, 2013 2 commits
  3. 13 Oct, 2013 17 commits
  4. 12 Oct, 2013 10 commits
  5. 11 Oct, 2013 10 commits