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Subject: Re: SMP variability some real data to look at (now three 2cpu runs)

Author: Robert Hyatt

Date: 21:29:02 09/05/02

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pos        1cpu       2cpu          2cpu          2cpu
 1         153      89 (1.72)     88 (1.74)     90 (1.70)
 2         139      90 (1.54)     90 (1.54)     90 (1.54)
 3         130      82 (1.59)     87 (1.49)     87 (1.49)
 4         176     100 (1.76)     99 (1.78)    100 (1.76)
 5         147      95 (1.55)     99 (1.48)     87 (1.69)
 6         135      77 (1.75)     77 (1.75)     78 (1.73)
 7          92      50 (1.84)     50 (1.84)     50 (1.84)
 8         149     104 (1.43)     89 (1.67)     90 (1.66)
 9          80      60 (1.33)     62 (1.29)     60 (1.33)
10         155      82 (1.89)     76 (2.04)     75 (2.07)
11         142      80 (1.77)     80 (1.77)     82 (1.73)
12         105      76 (1.38)     76 (1.38)     76 (1.38)
13         149     105 (1.42)    105 (1.42)    107 (1.39)
14         147     104 (1.41)     87 (1.69)     74 (1.99)
15         150      86 (1.74)     86 (1.74)     86 (1.74)
16         159      73 (2.18)     72 (2.21)     72 (2.21)
17         158      97 (1.63)     97 (1.63)     77 (2.05)
18          85      42 (2.02)     41 (2.07)     42 (2.02)
19         125      61 (2.05)     63 (1.98)    103 (1.21)
20         160     112 (1.43)    117 (1.37)    109 (1.47)
21         156      73 (2.14)     62 (2.52)    103 (1.51)
22          77      60 (1.28)     73 (1.05)     60 (1.28)
23         134      93 (1.44)     95 (1.41)     97 (1.38)
24         131      84 (1.56)     82 (1.60)    115 (1.14)
  average speedup->    (1.66)        (1.69)        (1.72)


OK... some more food for thought.

1.  The overall average speedup is "smoother" than I thought.  I am going to
add the other computational approach to show the average of the 24 speedups,
and then the total speedup computed by dividing the sums of the times in the
columns...

2.  There is a interesting variability.  A few positions are pretty much
"rock solid" in their times.  Like #18, and a few others.  A few are
all over the spectrum, #24 is one, but others like #14 are really bouncing
around too.

3.  Each run produces 2-3-4 super-linear speedups, and a couple of
positions are consistent.  That causes me some concern that move ordering
is having problems there and I am interested in the "why" of that...

4. The fail high percent for a wild position seems normal (91% for #14 for
example).

5.  the fail high percent for the superlinear positions also seems sane.  But
since a couple of positions do it every time, I'm going to look at some partial
trees to see what is up with that.  Although super-linear is not unexpected, I
am seeing more than I did with CB.  Perhaps the fact that CB's evaluation didn't
produce these enormous positional scores kept the tree shape more under control,
I don't know (yet).

6.  It looks like the 1.7X speedup for 2 cpus is pretty solid here as well,
as I had seen in the past...

I have one more of these running, when it is done I will produce one final
table and then maybe queue up 4 of the 3cpu tests and do it again.  I am
pretty sure the variability will climb with the number of processors...

If anyone wants the large raw data logs, let me know, I will save them for a
while.  If anyone wants to check my eyeball copying of the data, (the times)
that would certainly be good, but you will need the raw logs.




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