Scaling Cores, deciding the core usage

[dilip_viswanath]

Hi,

I am a naive user of TBB with my intel centrino duo machine.

I am currently doing a project of parallelizing Sudoku solving.

I have accomplished the program with my 2 cores.

I have the following questions on benchmarking its performance:

1)Can we decide the number of cores that TBB can operate on? This is to see the speed up happening between using 1 core and 2 cores. By default it is using both the cores.

2)I have only 2 cores. But i would also like to see or estimate how much will be the time taken when operated on more cores. Is there any emulators for multicore or any formula by which i can estimate the time taken when more cores are added? Or how else can i do the same?

3)Can i calculate the runtime memory usage by my algorithm using TBB?

btw, i am using ubuntu for execution.

Thanks a lot.

[Dmitry_Vyukov]

1. Yes, you can pass desired number of worker threads to constructor of tbb::task_scheduler_init.

2. Well, there is Intel Parallel Advisor which can kind of predict scalability for higher number of cores. However I suggest to run the program on a real machine, that will give more precise results.
You may use Intel Parallel Universe service to test your program on a machine with 16 hardware threads:
http://paralleluniverse.intel.com/

3. On linux you can use top for that.