Author: Gian-Carlo Pascutto
Date: 15:31:25 08/08/02
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On August 08, 2002 at 18:26:18, Aaron Gordon wrote: >On August 08, 2002 at 16:40:14, Gian-Carlo Pascutto wrote: >> >>The latency will be important, yes, because you will spend the time waiting for >>the data to come from the main memory. But bandwidth? Each probe will be exactly >> the size of one cacheline or a small multiple thereof. >> >>You're not moving huge continous chunks of RAM back and forth in hashing, but >>randomly distributed tiny amounts of data. What will determine your speed is not >>the bandwith but the latency. >> >>-- >>GCP > >Thats odd.. because when I tested with Cachemem the latencies between the two >settings were basically identical.. yet I get this boost from a 57% memory >increase. If you'd like you can do similar tests yourself and I can provide you >with cachemem to test your latencies (and it does a mem bandwidth test). The speed increase could be due to some other part of the program having advantage to more memory bandwith. Pulling in a routine that was swapped out of the cache for example. If I look at your numbers, the speedup is pretty much irrelevant of the hash size for most engines, so that would support the above. -- GCP
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