I am using xeon x5680 3.33GHZ dual cpu with 6 cores each, windows 7 64-bit 12GB ram.
I am runnig a filter on a image of size 640X480.
Using single thread to apply the filter on the image results 6.5 ms run time.
Moving to 2 threads eachhas its own image (same size - 640X480) and data structrues I get 7.4ms.
The performance keeps getting worse as I increase the number of threads - 20ms for 6 threads.
The same goes to the performance when using 7-12 threads.
In case of 7 threads - the threads binded to the first cpu (each to its own core) I get 20ms and the single one binded to core 7 (2nd cpu) runs at 7ms.
Overall - running 6/12 threads I get 3 times slowdown.
I know there should be certian slowdown - but 3 times is huge slowdown...