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SubjectRe: An elevator algorithm (patch)
On Sun, Sep 17, 2000 at 10:53:17PM +0200, Peter Osterlund wrote:
> The test2 elevator (assuming it is the same as the test8 version) in the

Yes it's the same in such respect.

> infinite latency case will always send the request with the lowest sector
> number to the drive. (The request queue will always be sorted, since the

Correct. And infact that's what is happening to 2.4.0-test8.

> elevator function degenerates to insertion sort.) Do you really suggest
> that this is as good as a real elevator algorithm?

No, I wasn't suggesting anything like that, I was only saying "don't complain
the elevator if the number you got out of test8 aren't good and you were
running on scsi". I guess the latency defaults are been set to a too high
default value exactly to be able to say that :). Jens also verified that a
default of 250 and 500 is good enough to not degenerate the tiotest numbers
(tested on 2.2.17 + elv-simple-1 patch), and with a 250/500 pair a `find` with
a `cp /dev/zero .` in background is not too bad (not like an deadlock and you
can visibly see the fix in action, however you'll definitely notice the cp in
background :).

Andrea
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