Author: Robert Hyatt
Date: 09:02:37 08/19/03
Go up one level in this thread
On August 19, 2003 at 05:39:17, Sune Fischer wrote: >On August 19, 2003 at 05:05:52, Gerd Isenberg wrote: > >Hi Gerd, > >>>Hmm, I don't really understand what that means. >> >>Using MMX/XMM does not contradict save threads. >>Os is responcable to save/restore all registers during context switch. > >thanks, that is good news. > >>>Is it possible to set the affinity of each thread, so that no context switching >>>occurs? That way they wouldn't mess up eachothers registers, would they? >>> >> >>Context switching occurs in milli second range. >> >>Gerd > >That doesn't sound ultra fast to me, but if it doesn't happen too often I guess >there is no problem. > >-S. A good O/S does this correctly. IE on Linux, threads don't "bounce" around very much, although there are plenty of interrupts that have to be handled by some processor or another. It's not a big deal. And since linux maps the kernel into every process at the same address, the map stuff doesn't have to be diddled with, and since X86 caches real addresses, caches don't have to be flushed frequently. The overall effect is that there is very little overhead to deal with in the normal case of N cpus, M threads, M <= N. For M > N, things can become problematic. But in chess nobody would want to do that.
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.