Author: Vincent Diepeveen
Date: 06:45:43 03/26/02
Go up one level in this thread
On March 25, 2002 at 09:31:06, Robert Hyatt wrote: >On March 25, 2002 at 07:05:26, Vincent Diepeveen wrote: > >>On March 24, 2002 at 21:42:32, Robert Hyatt wrote: >> >>>On March 24, 2002 at 21:10:57, Eugene Nalimov wrote: >>> >>>> >>>>We are talking about *absolute* performance, not about "nodes per MHz", right? >>>>Right now I can buy 2.2GHz x86 system, but I believe that fastest Alpha is 1GHz. >>>> >>>>I just run Crafty's "bench" on my 1.13Hz notebook and got 620knps, and I think >>>>that fastest x86 system will be faster than fastest Alpha. >>>> >>>>Eugene >>> >>>First, several mis-matches. >>> >>>1. I used gcc to compile Crafty, which Tim used to compile on the alpha. >>>So there is no compiler differences that are very significant... >> >>>2. I believe that Vincent has been saying that 64 bit processors simply >>>don't help. This is incorrect. They help significantly. There is no >>>technical reason why a 64 bit processor can't be clocked just as fast as >>>a 32 bit processor. The marketing force is simply not driving the development >> >>In a year or 10 you may be right, for now not a single 64 bits >>processor is clocked *near* 32 bits processors. >> >>You are still busy with stupid old 600Mhz 21264 processors. >> >>I tested myself on the mothers. They suck ass for computerchess, the >>only interesting is absolute performance, not how fast they are for >>600Mhz, because in CPU design the L1 and L2 cache are very important. >>If they didn't manage to clock those at 1.6Ghz, then that's their problem, >>not mine. > > >The 600mhz alpha produced 800K nodes per second for me. What processor do >you propose to do the same in the intel world. Knowing that 1ghz alphas >are available? > >That hardly "sucks". Unless you mean "it sucks the doors off those 32 bit >processors..." the 1Ghz alpha benchmark can be seen at specbench.org and it is slower than the 1.6Ghz XP2000. 122 versus 102. So 20% Note that they even cheated with the alpha benchmark by putting it at a quad. in reality this will be 30%. Best regards, Vincent > > >> >>For FPU, that's another story, that's not computer chess. > >Crafty doesn't use the FPU. It is a pure integer program... > > > >> >>>that way _yet_. But if someone wants to make a fast 64 bit chip, and believes >>>that they can market it to make a profit, then it will happen. >> >>Oh they will come, no doubts here that it will happen. Look at the >>McKinley design. Of course i can't pay a mckinley, but you could put >>perhaps 16 in parallel on a supercomputer. Will be perhaps even >>cheaper than the 10 million dollars for a 16 processor 21264 system. > > >you are really off on the price. By more than a factor of 10... > > > >> >>Of course clocked at 1Ghz each. >> >>>3. If you use gcc, your 1.13ghz notebook will be well off that pace, and >>>that will put it back into the light of a relatively equal comparison since >>>we would all be using the same compiler. >> >>This is dead wrong of course. you use the compiler that's fastest for >>the processor. If you look well at the specbench.org site you'll see >>that they also quote which compiler is used. > > > >What I said was not "dead wrong". DEC has a compiler for the alpha that is >much better. It is as much better than GCC as MSVC is better than gcc on the >intel platforms. > >I simply chose to use the _same_ compiler so that any difference was due to >the hardware, and not the optimizer... > > > >> >>Compaq C V6.4-214-46B59 >>Program Analysis Tools V2.0 >>Spike V5.2 DTK (1.461 46B5P) >>Compaq C++ V6.3-010-46B2F >> >>So they first analyzed the program and only after that recompiled it >>in order to get faster. >> >>It is very EASY to see that this is the fastest compiler for the Alpha. >> >>Amazingly for the XP2000 used was the intel compiler. Even though i >>don't trust this compiler at all for my software. >> >>>I was personally far more interested in the nps per megahertz since that seemed >>>to be the point vincent was attacking the alpha on, and the numbers don't >>>support his argument at all... >> >>No that's not interesting Bob. You know it and i know that they can >>easily clock L1/L2 cache at 1Ghz nowadays, but try to clock it at >>2Ghz!! > >L1/L2 at 2ghz is not a problem. SRAM can run as fast as you want it. DRAM >is another thing however.. > > > >> >>Of course a machine at 2.2Ghz or 1.67Ghz is going to have more problems >>clocking the caches higher. >> >>The only INTERESTING thing is how fast a processor + compiler performs >>for a program. If you build a 1Ghz processor, then it gotta beat >>a 2Ghz K7 simply. If it doesn't, THEN YOU ARE SLOWER. > > >For Crafty, it _does_ beat the K7 when running on a 1ghz alpha... > >that was my point. > > > > > >> >>>>>I don't know the specifics about the dual, but it was only 1.5X faster. We >>>>>later improved this a lot as the "lock" facility we used to start with was >>>>>very slow on the alpha architecture. >>>>> >>>>> >>>>> >>>>> >>>>>> >>>>>>Relative to the 1.67Ghz from the K7 the alpha achieves like >>>>>>a 102/122 x 1.667Ghz = 1.394Ghz K7 >>>>> >>>>> >>>>>Show me that 600mhz K7 that can do .8M nodes per second with crafty... >> >>Show me the alpha that can beat a 1.67Ghz XP, YOU WILL NOT FIND IT. >>In fact it is 30% slower even for CRAFTY which is supposed to profit >>from 64 bits. > >OK... first let's stick with the 600mhz 21264 before going to the 1ghz >version, since I have actual data from that processor. Do you think that >XP will do 800K? I don't. Dual 1.4 athlons did about 1M nodes per sec >last time I tried. Dual 600 alphas did 1.2M. The 1ghz parts are faster but >I have not actually run on them personally, and only have a small bit of data >from others that have. > > > > >> >>So a 32 bits processor doing 3 instructions a clock >>is kicking the HELL out of a 64 bits processor doing 4 instructions a clock, >>the 32 bits processor being clocked higher only 60%. > > >You've yet to show me _any_ 32 bit processor that is "kicking the hell" out >of an alpha... > > >> >>VERY HARD DATA!! >> >>Alpha sucks simply bigtime for the kind of integer operations a chess >>program is using, that's a *logical* conclusion to draw. > > >Not for the kind of integer operations _I_ do... > > >> >>And yes, the alpha compiler is using many instructions to remove branches, >>the X86 guys didn't invent those themselves... >> >> >> >>>>>Then I'll be a believer, not now... >>>>> >>>>> >>>>>> >>>>>>In theory the 4 instructions a clock for alpha versus >>>>>>3 instructions a clock for K7 give 33% speedup: >>>>>> >>>>>>1.000 Ghz + 33% = 1.333Ghz >>>>>> >>>>>>It achieves however 1.394Ghz >>>>>> >>>>>>In short i am missing the speedup for being 64 bits at all! >>>>> >>>>> >>>>>Because you are looking at the wrong data.. :) >>>>> >>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> >>>>>>> >>>>>>>>> >>>>>>>>>>-Tom
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