Assign Mutex to each Thread

Question

Hello I have a function and i would like to let a list/array of Threads run parallel in it (inorder to protect critical sections in it). I thought I'd create List and assign each one to a different Thread: for( int i =0; i { arrmutex[i] = new mutex(); } and in the function i would like to lock with a arrmutex.elementAt(someThread).waitOne() -> a specific variable It tells me that i cannot do that cause my mutex list is not initialize AND the lock wouldn't work.. Can you please help me figure out how to initialize a list/array of mutexes? and how to assign each thread a mutex? Thanks

Vulpes · Answer

However you look at it if it's going to be thread-safe only one thread can be allowed to enter the critical section of code at a time and so there's no point having more than one Mutex. If you're wanting to increase parallelity and have multiple cores (or processors) perhaps you should be looking at the parallel programming features that were introduced in .NET 4.0. To get a flavour of what can be done here check out this article: http://www.c-sharpcorner.com/UploadFile/vendettamit/parallel-programming-using-new-tpl-library-in-net-4-0/

roy doron · Answer

Vulpes I anderstand what you are saying.. and it makes sense.. but how can i synchronized bewteen multiple threads inorder to maximize parallelity? Should i create an array of mutexes? Should i create mutexes as number of the threads? Or 12 mutexes is enough? What is the best way to do that? Thank again..

Vulpes · Answer

I'm struggling to understand why you'd do want to assign a mutex to each thread? The whole point of a mutex is that it should be accessible to multiple threads - but only one at a time should be able to acquire and release the lock - to protect a critical section of code. Also mutexes tend to be restricted to inter-process synchronization in practice as they are about 50 times slower than normal 'monitor' locks.