Author: Robert Hyatt
Date: 18:17:01 11/11/02
Go up one level in this thread
On November 11, 2002 at 15:41:48, Bob Durrett wrote: > >I am a non-programmer but assume that all professional programmers know all >about optimizers. Sounds like a good thing to have, anyway. : ) > >So far, we have been talking about the case where there is only one big program >running on the computer and that is the chess engine [& GUI maybe]. But many >people [I presume] also run Office or Word and maybe other software. I almost >always have CB8 running when using Fritz, for example. Perhaps running several >big programs at once would cause the operating system to be more busy? > Yes, but the overhead for such is expected and all systems will lose a tiny bit of time doing context switches. Some worse than others. But the usage Vincent was describing makes no sense, as he said "one console program". >We have also been assuming that the computer would have ample RAM. However, >maybe not everybody has an expensive computer with tons of RAM. There may be >competition for the available RAM, and the OS would be one of the competitors. > >So, can the conclusions reached so far be extended to these cases too? > No system pages efficiently, but that is a totally different issue to operating system overhead in normal usage. >Incidentally, why would the Fritz people write their program in assembly >language, essentially bypassing an "optimizer"? Does it make enough difference >to go to that much trouble? [Maybe the Fritz people think only in assembly >language? : ) ] > Because you can do better than the optimizer. You design the program, so you know more about the internals of the program. IE if you want to do some- thing like wtm=!wtm; the optimizer has to handle cases where wtm can be _any_ legal integer value. If I know that it is only zero or one, I can change that to a much faster XOR instruction. Because I know something the compiler doesn't. Ditto for lots of other common things. A switch. I don't have to check for the "out-of-range" values, as I _know_ there will be none. etc... >P.S. Note that I am trying to use plenty of smileys whenever I intend humor. > >Bob D. > > > >> >> >> >> >> >>>>On November 11, 2002 at 13:02:44, Bob Durrett wrote: >>>> >>>>>Would the engine perform significantly better using that dedicated operating >>>>>system? [As compared to using a commercially available OS] >>>> >>>>You can get an idea of how much time is used by the OS. On my computer I look >>>>under Task Manager and it says: >>>> >>>>Image Name CPU Time >>>>System Idle Process 6:19:14 >>>>IEXPLORE.EXE 0:02:16 >>>>msdev.exe 0:01:22 >>>>Explorer.exe 0:00:53 >>>>System 0:00:22 >>>> >>>>And so on. So I have over 6 hours of idle time, and the next biggest chunk of >>>>CPU usage time was by Internet Explorer, of a whole 2 minutes. That means there >>>>is 99.5% of the CPU time that could have been used by a chess program. So the >>>>question is whether or not a 0.5% increase in speed is going to mean >>>>"significantly better" results. I think not.
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