Author: Tom Kerrigan
Date: 11:54:28 05/30/00
Go up one level in this thread
On May 30, 2000 at 14:36:24, Gian-Carlo Pascutto wrote: >On May 30, 2000 at 12:50:33, Tom Kerrigan wrote: > >>If you're not hashing during quiescence, how are you getting hit rates around >>40%? That's more than my percentage of non-quiescent nodes, period... > >I remember seeing my hitrate DROP by adding quiescence hashing...a lot >more stuff goes in, the tables are probed a lot more, but q-positions >do not seem to be searched as often as normal ones are, hence less hits. > >-- >GCP I just ran a test and over 90% of my nodes are qsearch() nodes. So it's not possible for me to have a hash table hit rate over 10%. So a 40% hit rate is pretty amazing. I assume that when Bob says he expects a 25% hit rate, he means 25% of the times that the hash table is probed, and not 25% of the nodes. Which means that more work needs to be done to estimate the speedup from the optimization that started this thread, i.e., the equation becomes: speedup = (% hit rate) * (% hash probes) * (% hash move cutoffs) * (% of time spent doing move generation) Throwing in some extremely optimal numbers, the result is: 0.5 * 0.2 * 0.5 * 0.2 = 1% So I think the best you can hope for is 1%. Seems like too much work for too little, to me. -Tom
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