Re: [PATCH] Time sliced CFQ #2

Jeff Sipek
2004-12-04T16:39:53Z

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On Sat, Dec 04, 2004 at 11:49:21AM +0100, Jens Axboe wrote:
> Hi,
>
> Second version of the time sliced CFQ. Changes:
>
> - Sync io has a fixed time slice like before, async io has both a time
> based and a request based slice limit. The queue slice is expired when
> one of these limits are reached.
>
> - Fix a bug in invoking the request handler on a plugged queue.
>
> - Drop the ->alloc_limit wakeup stuff, I'm not so sure it's a good idea
> and there are probably wakeup races buried there.
>
> With the async rq slice limit, it behaves perfectly here for me with
> readers competing with async writers. The main slice settings for a
> queue are:
>
> - slice_sync: How many msec a sync disk slice lasts
> - slice_idle: How long a sync slice is allowed to idle
> - slice_async: How many msec an async disk slice lasts
> - slice_async_rq: How many requests an async disk slice lasts

This looks very nice. And from your previous post (with version #1) it
would look like you made my attempt at io priorities easier. We'll see
;-)

Thanks,
Jeff.

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