Re: stochastic fair queueing in the elevator [Re: [BENCHMARK] 2.4.20-ck3 / aa / rmap with contest]

Rik van Riel
2003-02-10T21:34:15Z

On Mon, 10 Feb 2003, Kurt Garloff wrote:

> Readahead kills seeks and command overhead at the expense of maybe
> transfering data needlessly over the bus and consuming RAM.
>
> AS kills seeks. (At the expense of delaying some IO a tiny bit.)
>
> If unecessary seeks are the main problem, with AS smaller READA is
> possible. If command overhead is a problem, READA needs to be large.

Think about reading inode blocks or a bunch of related .h
files. We can't nicely do readahead in either of these
scenarios, but AS should take care of them nicely...

Rik
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