Author: Joachim Rang
Date: 05:01:00 11/25/04
Go up one level in this thread
On November 22, 2004 at 13:02:36, Martin Baumung wrote: >On November 22, 2004 at 11:23:53, Robert Hyatt wrote: > >>On November 22, 2004 at 10:48:02, Steve Maughan wrote: >> >>>I have a relatively new machine that has a P4 with Hyperthreading. I've >>>recently installed Shredder 8 and Gandalf 6. When playing a match I switched to >>>the Task Manager to look at the memory usage and noticed that when Gandalf was >>>thinking, according to the TM, it was only using 50% of the CPU while Shredder 8 >>>was using 100% (both had Ponder = off). On further investigation Shredder was >>>using 2 threads in the engine. Looking at the speed, both were getting >>>approximately the same nps which is inline with other machines I have tested >>>them on. >>> >>>So the question is - does the Task Manager report the CPU resource usage >>>incorrectly in this situation i.e. 50% = 100% usage of 1 processor? I'm >>>reasonably sure that this is the case but wanted to check. >>> >>>Thanks, >>> >>>Steve Maughan >> >> >>It is difficult for _any_ program to figure out what is going on, since >>hyper-threading makes the O/S think there are two equal CPUs, when there really >>is not... for engine vs engine you should turn it off in the BIOS... > >maybe a silly question, but why should one turn HT off - at least for engine >matches without pondering? So far I didn't encounter any problems. I've only >tried Shredder 8, but it gets a few extra nps with HT. > >Cheers, > >Martin because Shredder 8 will play weaker. It will gain a few nps but timetodepth and timetosolution will increase, since Shredder has to deal with the paralell search overhead. You can verify this by yourself if you ran a testsuite with HT enabled and disbled. You will notice that the timetosolution will be better with HT disabled. regards Joachim
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.