Messages in this thread | | | Date | Thu, 18 Mar 1999 20:26:40 -0800 | From | Yasushi Saito <> | Subject | Re: disk head scheduling |
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Arvind Sankar writes: > This patch breaks the code. The current algorithm used is that the elevator > stops at intermediate floors when going up, but not when going down. So it > is ok to add a floor above the top one on the current trip, or below the > lowest on the next.
Thanks for clearing up my confusion. Now I understand what the original code does.
What I tried to implement was two-way elevator seeking (SCAN). In my tiny benchmark that let many threads write on random files, SCAN showed a throughput improvement of anywhere between 0 to 20%. But I also noticed benefits in the original algorithm (it's fairer), so I don't know if my change makes sense.
yaz
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