Re: 2.5.48-mm1

William Lee Irwin III
2002-11-22T01:04:41Z

On Thu, Nov 21, 2002 at 04:04:25PM -0500, Bill Davidsen wrote:
> This is purely a performance decision. If you want to avoid bad latency on
> reads then you have to throttle writes. The loop_thread will make the
> system just as slow as a user application writing the same number of
> pages.
> If you want io scheduling you will deliberately slow writes to let reads
> happen in reasonable time. And vice-versa I imagine, although I don't
> think I've seen that case.

Not entirely so. This is just a scheduling decision that has to
discriminate between blocking and nonblocking requests and prevent
starvation of the blocking requests. Write throttling is an
oversimplification that functions poorly.

Bill