Author: Robert Hyatt
Date: 11:54:33 08/25/03
Go up one level in this thread
On August 25, 2003 at 13:49:46, Angrim wrote: >On August 24, 2003 at 21:50:28, Robert Hyatt wrote: > >>On August 23, 2003 at 03:45:09, Johan de Koning wrote: >> >>>On August 22, 2003 at 10:45:11, Robert Hyatt wrote: >>> >>>>On August 22, 2003 at 02:53:06, Johan de Koning wrote: >>>> >>>>>On August 21, 2003 at 11:29:49, Robert Hyatt wrote: >>>>> >>>>>>On August 21, 2003 at 03:16:35, Johan de Koning wrote: >>> >>>[snip] >>> >>>>>>>Hence I dare to ask: 25% of what? >>>>>> >>>>>>NPS went _up_ by 25%+. So total engine speed. >>>>>> >>>>>>This was changed in Crafty version 9.16, which dates back many years. >>>>> >>>>>Whoah! This is *very* hard to believe. >>>>>There must have been something severely wrong with 9.15 then (continuing chache >>>>>trashing comes to mind, but that's just guessing). More likely, this number does >>>>>not come from a clean comparison of copy/make versus make/unmake. >>>> >>>>The _only_ change made was to replace copy/make with make/unmake. Think about >>>>the math. >>> >>>Thinking about the math is easy. Doing the math in order to get valid results is >>>much harder since it requires facts to start with. >>> >>>> Copy/make copies 256 bytes+. Once _every_ node. On today's >>>>hardware, my dual xeon 2.8, I search about 2.4M nodes per second. or about >>>>400ns per node. Copying 256 bytes is certainly going to show up on the radar >>>>in a significant way, when it gets done once every 400 ns. >>> >>>To start simple, at 2.4 MN/s the average node takes 833 ns, or 2333 cycles. >>>That's a fact. :-) >> >>OK.. Fact #1. Your calculator is _broken_. :) >> >>Enter 1 / 2400000 and hit the = button. >> >> >>You will get 417 nanoseconds. You are off by a factor of two, somehow. >> > >I'd guess that he is taking into account that it is a dual cpu system. >So 833 ns per node, but you can do two nodes at once. This seems >reasonable to me. > >Angrim Perhaps. But even that is wrong. On my dual, I use SMT so I run four nodes at a time. :)
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