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On Dec 5, 2003, at 7:18 AM, Thor Lancelot Simon wrote:

> One thing I'm not so sure about is using a FCFS queue for the "time
> sensitive" requests.  I think that the average latency for requests 
> from
> that queue is probably significantly increased by using FCFS rather 
> than
> the increasing-block-number sort, because we lose the benefit of
> readahead, which will be particularly severe if the queues are long.  
> The
> sort seems particularly likely to be beneficial given the rather large
> number of requests we take from the queues in a "burst" and the 
> consequent
> likelihood that we'd get a lot of track cache hits.

Yah, I agree with this analysis.

         -- Jason R. Thorpe <thorpej@wasabisystems.com>


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