Hi Richard, I'm very much interested in core 2 duo performance and would appreciate hearing what others have experienced in this regard. I don't know what OS you use, but here are my experiences so far with Linux:
I'm a little disappointed with the speed of a single threaded application on my core 2 duo system. I just bought a desktop e6700 processor and I run 64 bit linux on it. I originally wrote my UCT program on a 32 bit 2.4 GHz pentinum 4. Whether I SHOULD be disappointed or not I don't know - it's just that I had higher expectations based on all the hype. The ratio of performance I get is about 1.7. So it's as if I'm running on my old computer with the clock (and everything else) sped up 1.7 times. However, the core 2 in my machine is clocked faster than my old machine, so clock for clock I compute roughly 1.53 percent increase in performance for a core 2 duo. Obviously, those are rough numbers because each application can vary significantly based on many factors. I'm sure you know all about this but I'll enumerate them here anyway: 1. GCC is not yet optimized to handle core 2 duo (and that's what I use.) 2. The program was optimized on my old machine. I did stuff that made it faster on THAT machine. If I developed it from scratch on the new machine, it would probably be faster since I tend to profile, test, and optimize for what works on the machine I develop on. 3. core 2 duo is 64 bit and my program does nothing to take advanatage of any of this. 4. Of course it's pretty nice having 2 cores! 5. The core 2 is highly responsive to over-clocking but I have a cheap system. I doubt my motherboard and memory will support much overclocking and I haven't tried. Mabye I will someday. One thing I can say is that the system is very robust, it almost seems like I can run an unlimited number of things without it bogging down thanks to 2 processors and 2 Gigabytes of memory. The intel compiler is much better I understand and you can get it for linux too, but I'm too cheap to do this. GCC will eventually improve for core 2 duo, hopefully I won't have to wait too long. FYI here is the compiler flags I use for gcc 4.1: CFLAGS= -Wall -O3 -march=nocona -pipe -fomit-frame-pointer -fno-strict-aliasing Some of those make very little difference. This is the output of "cat /proc/cpuinfo" for one of the processors: processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 CPU 6700 @ 2.66GHz stepping : 6 cpu MHz : 2667.000 cache size : 4096 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl vmx est tm2 cx16 xtpr lahf_lm bogomips : 5325.28 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: - Don On Thu, 2007-02-22 at 07:51 -0800, Richard J. Lorentz wrote: > 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/ _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
