Messages in this thread |  | | Date | Mon, 11 Nov 2002 06:23:36 +0100 | From | Andrea Arcangeli <> | Subject | Re: [BENCHMARK] 2.4.{18,19{-ck9},20rc1{-aa1}} with contest |
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On Sun, Nov 10, 2002 at 09:10:41PM -0800, Andrew Morton wrote: > Andrea Arcangeli wrote: > > > > from your description it seems what will happen is: > > > > queue 3 5 6 7 8 9 > > > > I don't see why you say it won't do that. the whole point of the patch > > to put reads at or near the head, and you say 3 won't be put at the > > head if only 5 writes are pending. Or maybe your bypasses "6 writes" > > means the other way around, that you put the read as the seventh entry > > in the queue if there are 6 writes pending, is it the case? > > Actually I thought your "queue" was "head of queue" and that 5,6,7,8 and 9 > were reads.... > > If the queue contains, say: > > (head) R1 R2 R3 W1 W2 W3 W4 W5 W6 W7 > > Then a new R4 will be inserted between W6 and W7. So if R5 is mergeable > with R4 there is still plenty of time for that.
yes, the fact it's "near" and not exactly in the head as I originally thought, makes it less likely that it slows things down, even if it theoretically still could for some workload, overall it seems a worthwhile heuristic.
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