I currently have a code block like this

UINT8* u = getResult();
for (UINT64 counter = 0; counter < MaxCount; counter  )
{
    for (UINT64 index = 0; index < c_uOneMB;   index)
    {
        *u   = genValue();
    }
}

Now in order to make this run faster. I am doing something like this. Basically splitting the inner thread into a method. However I have two concerns which I am not sure how to tackle.

1. *u how do I handle that?
2. Before calling doSomethingElse() all the threads need to .join()

Any suggestions on how to accomplish that?

void doSomething(UINT8* u)
{
      for (UINT64 index = 0; index < c_uOneMB;   index)
      {
          *u   = genValue();
      }
}

UINT8* u = getResult();
for (UINT64 counter = 0; counter < MaxCount; counter  )
{
    std::thread t(doSomething,u);
}

doSomethingElse();

CodePudding user response：

With little details you have provided I can give only this:

std::generate_n(std::execution::par, getResult(), MaxCount * c_uOneMB, genValue);

• https://en.cppreference.com/w/cpp/algorithm/generate_n
• https://en.cppreference.com/w/cpp/algorithm/execution_policy_tag

CodePudding user response：

Best way to parallize this for loop with multiple threads

Best way depends on many factors and is subjective. In fact, sometimes (perhaps most of the time) non-parallelised code is faster. If speed is most important, then the best way is whatever you have measured to be fastest.

Using the standard library algorithms is usually straightforward:

std::generate_n(
    std::execution::par_unseq,
    u,
    MaxCount * c_uOneMB,
    genValue);