CODEWITHSUNDEEP
c++multithreadingboost
定坤宋
定坤宋

Reputation: 45

boost::lockfree::queue is eating up my CPU

So I wrote a multi-thread program using boost::lockfree::queue, and the code is pretty much the same as the given example http://www.boost.org/doc/libs/1_62_0/doc/html/lockfree/examples.html. Well, I have 4 queues and the data is a struct rather than int.

The problem is that my program eats up 95% of my cpu when running and it's super slow. After a little investigation I found out that boost::lockfree::queue::pop takes 80% of the cpu usage, which isn't surprising because of these two loops

while (!done) {
    while (queue.pop(value))
        ++consumer_count;
}

Is there anything I can do to reduce the cpu usage, or should I upgrade my CPUs? I am using boost 1.61, visual studio 2015 on windows 10, btw.

Thanks so much

Upvotes: 1

Views: 687

Answers (1)

Ivan Baidakou
Ivan Baidakou

Reputation: 783

What did you expected? The following piece of code is the same as yours (in terms of eating CPU)

int counter = 0;
bool condition_1 = false;
bool condition_2 = false;
while(!condition_1) {
  while(!condition_2) {
    ++counter;
    condition_2 = true;
  }
}

What you need, IMHO, is some notification mechanism (e.g. condition_variable), when poll queue. Otherwise, constantly polling it, obviously, eats cpu.

Upvotes: 1

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