This is not accurate. In my experience you should expect a substantial performance increase from hyperthreading. (For my program on an i7-3930 it was something like a 40%, Zen got a similar number, others on this list have claimed even higher numbers, e.g., see: http://dvandva.org/pipermail/computer-go/2012-August/005298.html).
Erik On Mon, May 12, 2014 at 5:06 PM, Mikko Aarnos <[email protected]> wrote: > CPU cores are meant to be used by a single thread only. You can use more, > but this rests on the assumption that two(or more) threads can effectively > utilize a single core without too much competition over resources. This > assumption is true in most situations, e.g. when we have to wait for IO or > server queries or things like that often, and in these cases using HT can > give a small performance boost. Now, here we are only utilizing the CPU. In > this case the threads are only getting into each other's way. The effects of > this can be seen very clearly with your program. It seems to scale > perfectly, or very nearly so, as long as you don't use more threads than you > have actual cores on your computer. When you go above that limit the scaling > goes to hell and you get no improvement at all. The only way to solve your > scaling problem is to get rid of the competing threads by turning off HT. I > did this and have never looked back. > > -Mikko Aarnos > > _______________________________________________ > Computer-go mailing list > [email protected] > http://dvandva.org/cgi-bin/mailman/listinfo/computer-go _______________________________________________ Computer-go mailing list [email protected] http://dvandva.org/cgi-bin/mailman/listinfo/computer-go
