Author: Anthony Cozzie
Date: 09:17:45 01/02/04
Go up one level in this thread
On January 02, 2004 at 11:45:57, Matthew McKnight wrote: >On January 02, 2004 at 11:24:19, Steven J. Brann wrote: > >>On January 02, 2004 at 11:05:41, Anthony Cozzie wrote: >> >>>On January 02, 2004 at 09:57:38, Jasmine Baer wrote: >>> >>>>I've seen it written that under the following conditions: >>>> >>>>1. Engine vs. Engine match or tournament >>>>2. Held on a single computer with a single processor >>>> >>>>having ponder=ON(or Permanent Brain in the Fritz GUI) will impact the play of >>>>the engines since the each individual engine would not have full access to the >>>>processor during its own turn. >>>> >>>>First, is this true? >>>> >>>>Second, is this issue, if it actually is an issue, something that is eliminated >>>>by running a two-processor system? >>>> >>>>And, finally, does anyone have any solid insight on how ponder=off/on or >>>>Permanent Brain works on a Pentium 4 with Hyperthreading? >>>> >>>>Thanks. >>> >>>Ponder means that the engine thinks while its opponent moves. Since there is >>>only 1 cpu, and both engines are thinking, they get half the cpu. >>> >>>HT is garbage for computer chess. A pentium 4 is ONE core. HT is designed for >>>applications that spend most of their time in the memory system. >>> >>>anthony >> >>To me, my 3.0G HT machine is NOT garbage for computer chess. When it is >>thinking about a position it takes up 50% of the CPU and is still much much >>faster than my 1.9G P4 machine. When analyzing a position with my 1.9G P4, the >>machine would be rendered useless for using any other application while it was >>thinking about a position. >> >>So, HT enables me to accomplish other things on the machine at the same time ... >>email, reviewing this site, chat with video, Word, Excel ... and >>performance-wise its as if the chess program isn't running at all. I'm >>analyzing a position as I write this. > >Yes this is what HT does, but it's also what every other modern CPU does... >It's just Intel's latest buzzword for a well-known technology called pipelining. > I believe what the author meant by the word "garbage" is simply that you >shouldn't believe you _need_ a machine with HT for computer chess. > >Interestingly enough, pipelining benefits from you running more than one program >at a time. That is to say that if you were to run two processes, each using 50% >of the cpu for 1 hour, they would get more work done than the sum of work done >from both processes individually at 100% for one hour each. The increased >difference between the types of programs in the experiment, increases the >results. This is a product of the enormous clock rate!! The only way to get >such a speed is to try and run instructions simultaneously, and this is why you >do better when you run two completely different programs (i.e. working on >different things). HT has nothing to do with pipelining. It has to do with ILP and cache misses. anthony
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