Messages in this thread | | | Date | Wed, 5 Apr 2006 11:20:06 +0200 | From | Jens Axboe <> | Subject | Re: CSCAN I/O scheduler for 2.6.10 kernel |
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On Tue, Apr 04 2006, Bill Davidsen wrote: > Vishal Patil wrote: > >Maintain two queues which will be sorted in ascending order using Red > >Black Trees. When a disk request arrives and if the block number it > >refers to is greater than the block number of the current request > >being served add (merge) it to the first sorted queue or else add > >(merge) it to the second sorted queue. Keep on servicing the requests > >from the first request queue until it is empty after which switch over > >to the second queue and now reverse the roles of the two queues. > >Simple and Sweet. Many thanks for the awesome block I/O layer in the > >2.6 kernel. > > > Why both queues sorting in ascending order? I would think that one > should be in descending order, which would reduce the seek distance > between the last i/o on one queue and the first on the next.
Then it wouldn't be CSCAN, now would it? :-)
-- Jens Axboe
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