Subject: Re: i/o scheduling (was Re: NEW_BUFQ_STRATEGY)
To: YAMAMOTO Takashi <>
From: Thor Lancelot Simon <>
List: tech-kern
Date: 12/13/2003 22:13:04
On Sun, Dec 14, 2003 at 11:16:53AM +0900, YAMAMOTO Takashi wrote:
> hi,
> > 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.
> then how do you think about the attached one?

Just at a first glance, why three queues?