unreasonable multiple Whetstone results

[GoogleCodeExporter]

What steps will reproduce the problem?
1. ./Run arthrimetic
2. ./Run -c 4 arthrimetic
3. ./Run -c 8 arthrimetic
4. ./Run -c 12 arthrimetic
5. ./Run -c 16 arthrimetic

What is the expected output? What do you see instead?

the system CPU has only 4 cores.

-c 4 ~ 16 should have result slightly less than 4x of single process test 
result.
but, the results are:
4: 3380.9       
8: 6756.2   
12: 10130.1 
16: 13504.2

What version of the product are you using? On what operating system?
unixbench 5.1.3
3.2.0-4-amd64 #1 SMP Debian 3.2.63-2 x86_64 GNU/Linux
one Intel XEON E3-1225

Please provide any additional information below.
also got same kind of result on a Apple MBP, with Core i7 3615, 4C8T

1: 959.8    
4: 3902.9   
8: 7139.1
12: 10673.6
16: 14252.6

Original issue reported on code.google.com by [email protected] on 5 Dec 2014 at 2:38