The hardware portion of this topic is very important, at least to me
since I'm in the market for a new laptop. :) The comment "today the
frequency means nothing" is my main concern and I worry even more if I
need to investigate all the other numbers associated with the CPU. I bet
the laptop manufactures won't even be able to tell me things like the
"stepping number", anyway! So, what should I be looking for in a
processor if I want to get the most out of my single threaded UCT
program? Assuming I go with Intel, will I get more simulations out of a
Core2 machine than a Core machine, say, with the same clock speed?
Perhaps the most interesting question for me is: How will a Core2 (duo?)
2.33 GHz compare with my existing P4 3.2 GHz? In any case I guess I will
have to retool the program to be multi-threaded to take advantage of the
dual core. Should I also be worrying about converting to 64-bit?
Thanks!!
-Richard
Sylvain Gelly wrote:
Hello,
I do not understand it. Maybe someone does?
I've made some tests on 2 core processors, and I have strange results.
Some of 2 core processors got results exactly 2x times worse than
they should.
Why?
I have no idea.
But 2.8 Ghz 2 core works exactly like my 1.4 laptop.
Also version of g++ does matter.
Here, from my experience, the following can matter a lot:
- version of g++ (g++ 4.1 gave me +50% against g++ 4.0 on an opteron!)
- version of the libc: even compiled with a modern compiler, a program
running on a machine with an old version of the libc can be very
significantly slower (-30% observed!).
- exact version of the processor: today the frequency means nothing,
nor the name of the processor. You have to check the exact numbers.
And I also observed that even the small numbers as the "stepping
number", matters. MoGo runs faster on my P4 3.4 Ghz than on a 3 years
newer P4 3.8 Ghz, which has also more cache. I ran test on other P4,
and the slower had a different stepping, that's all (all are dell
computers using same hardware).
- Measure of time: if you take the CPU time, on multiprocessor
machine, while using multithreading, sometimes the reported time is
not what you expect (generaly reported for all the threads), so when
you calculate the speed of playouts, you can have a 2x/4x factor.
Hope that can help,
Sylvain
_______________________________________________
computer-go mailing list
computer-go@computer-go.org
http://www.computer-go.org/mailman/listinfo/computer-go/
_______________________________________________
computer-go mailing list
computer-go@computer-go.org
http://www.computer-go.org/mailman/listinfo/computer-go/
