parallel programming

[chmcy]

hello, i am trying to make a parallel program using threads and i need some help. Actually i've got 2 threads an i want them to add the lines of two arrays and when one of the threads finish, get then next free line and make the calculations. How can i do that?
thanks

[r-senior]

Welcome :)

What language are you working in?

[chmcy]

hi! :) with c

[ofnuts]

hello, i am trying to make a parallel program using threads and i need some help. Actually i've got 2 threads an i want them to add the lines of two arrays and when one of the threads finish, get then next free line and make the calculations. How can i do that?
thanksSince the threads will likely take always more ore less the same time to process a line, why not avoid the problem and make one thread process the even lines and the other the odd ones?

[chmcy]

ok but how do we know that is the same time for each thread? if i have a huge table then there is a possibility the one of the threads to finish much earlier than the other right?

[ofnuts]

ok but how do we know that is the same time for each thread? if i have a huge table then there is a possibility the one of the threads to finish much earlier than the other right?Not really... I expect the number of instruction executed by each thread to process each line to be identical. If there are large execution time discrepancies between the lines, it means something is making you wait (swapping?) and then being multi-thread is moot... (I assume you want to run full-throttle on all cores... btw you may also want to look at SSE instructions if you haven't done so already).

[chmcy]

yeap u r right.. i actually wanted to try that.. having two threads running and when the one finish, doing the next job bt i think this wont be very effiecient.. :)