Author: Vincent Diepeveen
Date: 10:34:12 03/27/01
Go up one level in this thread
On March 27, 2001 at 09:36:54, Robert Hyatt wrote: >On March 27, 2001 at 08:52:15, Andrew Dados wrote: > >>On March 27, 2001 at 08:17:43, Vincent Diepeveen wrote: >> >>>On March 26, 2001 at 22:44:53, Robert Hyatt wrote: >>> >>>>On March 26, 2001 at 20:54:48, Dan Andersson wrote: >>>> >>>>>I have to agree that multibanked memory and lage cashe size are very beneficial. >>>>>Those factors could very well explain the superlinearity. >>>>> >>>>>Regards Dan Andersson >>>> >>>> >>>>I don't think the 4-way interleaving helps. That _barely_ lets the machine >>>>hold its own, memory-wise, because there are 4x as many cpus fighting over >>>>access to memory... making it nearly 4x faster just barely breaks even. The >>>>larger L2 cache may well make a difference, of course... >>> >>>You speak for Crafty. I speak for DIEP. >>>I'm doing 8 probes of at least 16 bytes an entry. >>>that's 128 bytes. >> >>My guess is big difference for SMP DIEP is running separate processes instead of >>threads. 8 probes is just icing on that cake. >> >>For what I know windows (unix too) will load each process to its own address >>space, so they will fight for L3 cashe. >>Or am I totally wrong here? >> >>-Andrew- >> > >This is correct. Threads share one address space so this isn't such a huge >problem... but your program with threads is slower as you need extra pointers everywhere except if you start using non-ansi C standards. How do i evaluate a board position in ansi-C using multithreading without needing to load an extra pointer? > > >> >>> >>>I also do that to get a possible evaluation out of hashtable as i store >>>evaluations in hashtable. >>> >>>So i do way more of those octo-probes as most progs try the hashtable... >>> >>>Further my whole program is made out of 'int'. So that means in short >>>that all kind of tables are 4 times bigger (in bytes) as they could >>>be. That means that when compared to some years ago i need quite some >>>accesses to main memory. >>> >>>Both the bigger L2 cache and the faster memory helps a lot then. >>> >>>Best Regards, >>>Vincent
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