DragonFly commits List (threaded) for 2008-06
DragonFly BSD
DragonFly commits List (threaded) for 2008-06
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cvs commit: src/sys/vfs/hammer hammer.h hammer_btree.c hammer_btree.h hammer_cursor.c hammer_disk.h hammer_inode.c hammer_io.c hammer_object.c hammer_ondisk.c hammer_transaction.c hammer_vfsops.c hammer_vnops.c

From: Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxxxxx>
Date: Tue, 17 Jun 2008 18:13:31 -0700 (PDT)

dillon      2008/06/17 18:13:31 PDT

DragonFly src repository

  Modified files:
    sys/vfs/hammer       hammer.h hammer_btree.c hammer_btree.h 
                         hammer_cursor.c hammer_disk.h 
                         hammer_inode.c hammer_io.c 
                         hammer_object.c hammer_ondisk.c 
                         hammer_transaction.c hammer_vfsops.c 
  HAMMER 56B/Many: Performance tuning - MEDIA STRUCTURES CHANGED!
  * MEDIA CHANGE: The atime has been moved back into the inode data proper.
    The nlinks field has also been moved.
  * PERFORMANCE: The CRC for cached B-Tree nodes was being run on every access
    instead of just the first time.  This was the cause of HAMMER's poor
    directory scanning performance and cpu-intensive write flushes.
    Adjusted to only check the CRC on the initial load into the buffer cache.
  * PERFORMANCE: The CRC for modified B-Tree nodes was being regenerated every
    time the node was modified, so a large number of insertions or deletions
    modifying the same B-Tree need needlessly regenerated the CRC each time.
    Adjusted to delay generation of the CRC until just before the buffer is
    flushed to the physical media.
    Just for the record, B-Tree nodes are 4K and it takes ~25uS to run a CRC
    on them.  Needless to say removing the unnecessary calls solved a lot of
    performance issues.
  * PERFORMANCE: Removed limitations in the node caching algorithms.  Now more
    then one inode can cache pointers to the same B-Tree node.
  * PERFORMANCE: When calculating the parent B-Tree node we have to scan the
    element array to locate the index that points back to the child.  Use a
    power-of-2 algorithm instead of a linear scan.
  * PERFORMANCE: Clean up the selection of ip->cache[0] or ip->cache[1] based
    on whether we are trying to cache the location of the inode or the
    location of the file object's data.
  Revision  Changes    Path
  1.86      +52 -13    src/sys/vfs/hammer/hammer.h
  1.55      +1 -4      src/sys/vfs/hammer/hammer_btree.c
  1.18      +1 -1      src/sys/vfs/hammer/hammer_btree.h
  1.31      +15 -21    src/sys/vfs/hammer/hammer_cursor.c
  1.38      +6 -3      src/sys/vfs/hammer/hammer_disk.h
  1.77      +40 -15    src/sys/vfs/hammer/hammer_inode.c
  1.43      +23 -0     src/sys/vfs/hammer/hammer_io.c
  1.70      +11 -9     src/sys/vfs/hammer/hammer_object.c
  1.59      +47 -62    src/sys/vfs/hammer/hammer_ondisk.c
  1.18      +7 -0      src/sys/vfs/hammer/hammer_transaction.c
  1.49      +2 -0      src/sys/vfs/hammer/hammer_vfsops.c
  1.72      +29 -27    src/sys/vfs/hammer/hammer_vnops.c


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