Author: Vincent Diepeveen
Date: 19:44:28 07/29/03
Go up one level in this thread
On July 29, 2003 at 21:43:11, Keith Evans wrote: >On July 29, 2003 at 20:41:37, Vincent Diepeveen wrote: > >>On July 29, 2003 at 18:18:31, Keith Evans wrote: >> >>>On July 29, 2003 at 17:35:01, Vincent Diepeveen wrote: >>> >>>>On July 29, 2003 at 17:14:52, Keith Evans wrote: >>>> >>>>>On July 29, 2003 at 17:04:44, Vincent Diepeveen wrote: >>>>> >>>>>>On July 29, 2003 at 16:13:19, Keith Evans wrote: >>>>>> >>>>>>>On July 29, 2003 at 16:00:20, Tord Romstad wrote: >>>>>>> >>>>>>>>On July 29, 2003 at 12:49:49, Keith Evans wrote: >>>>>>>> >>>>>>>>>You're perft performance seems pretty decent to me. >>>>>>>> >>>>>>>>Indeed. I just did a similar test with my own program on a Pentium 4 2.4 GHz. >>>>>>>>In the position after 1. e4 e5 2. d4 d5, my program generates 30 million moves >>>>>>>>per second. I guess I could speed it up somewhat, but I don't think I would >>>>>>>>come anywhere close to the speeds reported by Vincent and Angrim. >>>>>>>> >>>>>>>>My move genererator assigns all moves a move ordering score, and also >>>>>>>>determines which moves are checks. It generates legal moves only. >>>>>>>> >>>>>>>>But anyway, I don't understand why people spend so much time and energy on >>>>>>>>micro-optimising their move generators. Despite my slow movegen speed, my >>>>>>>>program spends only 1 or 2 percent of its time in the move generator. I >>>>>>>>guess most other programmers have similar numbers. >>>>>>>> >>>>>>>>Tord >>>>>>> >>>>>>>I'm personally interested in the performance of the move generator in a hardware >>>>>>>chess chip where it is a large percentage of the total cycles. If it were only >>>>>>>1-2% of the time then I wouldn't be interested. Of course a hardware move >>>>>>>generator can generate millions of NPS when only running at say 30 MHz, so it's >>>>>>>a totally different animal than a software generator running on a 3 GHz >>>>>>>processor. >>>>>> >>>>>>hardware doesn't work like that. you cannot store the moves. >>>>>> >>>>> >>>>>Huh? (Duh?) Where did I say that it pregenerates and stores the moves? Of course >>>>>it generates them incrementally. >>>> >>>>but i hope you realize how hard it is to order moves when all you have is 1 >>>>bound that gives how far the incremental generation is. >>>> >>>>but if you compare speeds. >>>> >>>>Say that each move costs 1 clock. that's 30 million moves a second at 30Mhz >>>>right? >>>> >>>>Brutus ran at 2002 WCC at something like 33Mhz. So that's 33 MLN a second. >>>> >>>>DIEP i generate way more than 33MLN a second at the 1.6Ghz K7 i had back then. >>>> >>>>At 2.127Ghz it is about 72MLN. this with slow RAM storage. It's probably >>>>relatively faster at a P4 generating moves because of the fast L1 cache there >>>>and everything runs within trace cache when doing a loop for a few millions of >>>>times. >>>> >>> >>>Can you do perft at 72 million NPS? (Actually traverse a tree?) If not then >>>you're quoting something different. You could use Chrilly's 7 cycle/node number >>>which should include everything to generate, make, and unmake moves. So at 33 >>>MHz that would be 4.7 MNPS. >> >>please do not compare perft with generating moves. >> >> >>perft is generating a NUMBER. not moves. >> >>do you understand? >> >>all you need is a number for perft. not moves. > >If you time perft then you get a node count and a time in seconds, therefore you >can get nodes per second out of it. If you want to measure correctness then you >can just compare the node count. If you want some measure of performance then >you obviously look at NPS. > >I think that this is obvious. Just search through the CCC archives and look for >people trying to optimize the NPS in perft. Not that I'm recommending optimizing >for that, but it's been discussed many times. > >My opinion is that if you're going to quote 72 million NPS in software and try >to compare that to a hardware implementation, then the easiest way is to compare >using a perft style test. If you're just setting up one position and generating >moves from that position repeatedly in a tight loop, then there's really no way >to compare that. Plus my belief is that the perft number is more representative >of the performance of the move generator under real conditions. > >Here's some perft output from crafty which I take to be the de facto perft >standard: > >Crafty v19.3 > >White(1): perft 5 >total moves=4865609 time=1.24 > >So to convert this to NPS 4,865,609 [nodes]/1.24 [seconds] = 3,923,878 >[nodes/second] > >Please explain why that is incorrect? What does diep get for this case? >73,000,000 NPS? I find that hard to believe. you are making a mistake. you still do not understand what perft is. perft is a number. you can get it faster by adding hashtables and such. it has nothing to do with generating semi legal or legal moves at all. it is just creating a number faster. and it's not only hashtables. ever thought of how you can speed up perft incredible by using an incremental attacktable? There is no need to generate *any* legal move at all for perft. If i use a fast 8 bits attacktable for it at a K7 then even without hashtable you can get already like tens of millions of nodes a second easily. that number divided by the time is your perft nps number. it has nothing to do with GENERATION. you just must smartly count how many there are *period*. generating a few millions of times the same move list in a position X is quite different from that. So the rest of the story written here i will not even read. Sorry. Bedtime here :) >(Let's assume that hash tables aren't in the picture, because that would mean >that you're not really measuring the performance of the move generator. Also >maybe there's a small chance that doing something like that might mask a problem >in somebody's movegen if they are using perft as a measure of correctness.) > >-Keith
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