How do I spawn threads on different CPU cores?

Question

Let\'s say I had a program in C# that did something computationally expensive, like encoding a list of WAV files into MP3s. Ordinarily I would encode the files one at a time

Answer 1

You can definitely do this by writing the routine inside your program.

However you should not try to do it, since the Operating System is the best candidate to manage these stuff. I mean user mode program should not do try to do it.

However, sometimes, it can be done (for really advanced user) to achieve the load balancing and even to find out true multi thread multi core problem (data racing/cache coherence...) as different threads would be truly executing on different processor.

Having said that, if you still want to achieve we can do it in the following way. I am providing you the pseudo code for(Windows OS), however they could easily be done on Linux as well.

#define MAX_CORE 256
processor_mask[MAX_CORE] = {0};
core_number = 0;

Call GetLogicalProcessorInformation();
// From Here we calculate the core_number and also we populate the process_mask[] array
// which would be used later on to set to run different threads on different CORES.


for(j = 0; j < THREAD_POOL_SIZE; j++)
Call SetThreadAffinityMask(hThread[j],processor_mask[j]);
//hThread is the array of handles of thread.
//Now if your number of threads are higher than the actual number of cores,
// you can use reset the counters(j) once you reach to the "core_number".

After the above routine is called, the threads would always be executing in the following manner:

Thread1-> Core1
Thread2-> Core2
Thread3-> Core3
Thread4-> Core4
Thread5-> Core5
Thread6-> Core6
Thread7-> Core7
Thread8-> Core8

Thread9-> Core1
Thread10-> Core2
...............

For more information, please refer to manual/MSDN to know more about these concepts.