cvs commit: src/sys/dev/disk/nata ata-queue.c

Matthew Dillon dillon at
Tue Sep 23 10:45:08 PDT 2008

dillon      2008/09/23 10:43:41 PDT

DragonFly src repository

  Modified files:
    sys/dev/disk/nata    ata-queue.c 
  Make two more changes to the ata request queue sorting code.
  * Do not try to sort write requests.  There's no point, the hard drive
    has a write cache and a much better understanding of the media topology
    and will sort the requests for us.
  * Move the freeze point every 16 requests instead of every 128 to further
    reduce the amount of reordering we allow to prevent older requests from
    being delayed indefinitely by newer requests.
    Note: the original ata code didn't code any limits at all, causing insanely
    long latencies during heavy disk I/O for no good reason.
  Reported-by: Hasso Tepper <hasso at>
  Revision  Changes    Path
  1.11      +17 -6     src/sys/dev/disk/nata/ata-queue.c

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