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Subject: Question about Crafty output

Author: Jeremiah Penery

Date: 00:17:26 05/29/02

Go up one level in this thread


On May 28, 2002 at 00:50:01, Mike Byrne wrote:

>modified nonsmp crafty 2:41
>
>Crafty v18.15 (1 cpus)
<SNIP>
>White(1): st 600
>search time set to 600.00.
>White(1): setboard 3q2k1/pp3rpp/2n4r/3pP3/P1pP1p1N/B1P3Pb/5P1P/R2QR1K1 b - - 0 >Black(1): go
>              clearing hash tables
>              time surplus   0.00  time limit 10:00 (10:00)
>         nss  depth   time  score   variation (1)
<SNIP>
>               14     9:32     ++   1. ... Rxh4!!
>              time=10:00  cpu=99%  mat=0  n=373223764  fh=95%  nps=621k
>              ext-> chk=24050595 cap=694863 pp=1593152 1rep=3845008 mate=51685
>              predicted=0  nodes=373223764  evals=53788687
>              endgame tablebase-> probes done=0  successful=0
>              SMP->  split=0  stop=0  data=0/32  cpu=9:56  elap=10:00
>
>===========================================================================
>modified smp crafty 1:37
>
>Crafty v18.15 (2 cpus)
<SNIP>
>White(1): setboard 3q2k1/pp3rpp/2n4r/3pP3/P1pP1p1N/B1P3Pb/5P1P/R2QR1K1 b - - 0 >Black(1): st 600
>search time set to 600.00.
>Black(1): go
>              clearing hash tables
>              time surplus   0.00  time limit 10:00 (10:00)
>         nss  depth   time  score   variation (1)
>starting thread 1
<SNIP>
>               14     4:19     ++   1. ... Rxh4!!
>              time=10:00  cpu=396%  mat=0  n=785776691  fh=97%  nps=1309k
>              ext-> chk=67658533 cap=922567 pp=2386265 1rep=8557559 mate=60987
>              predicted=0  nodes=785776691  evals=62997715
>              endgame tablebase-> probes done=0  successful=0
>              SMP->  split=1375  stop=124  data=13/32  cpu=39:39  elap=10:00
                                                            ^^^^^??

The SMP version has a node count (and NPS count) more than twice as high as the
single-CPU version, which seems pretty strange.

But the really strange thing is that the CPU time reported is what you would
expect to see on a 4-CPU system.  I'd like to know if others have similar
strange numbers for CPU time usage in an SMP environment, or if something funny
is going on here.

Thanks,
Jeremiah



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