Function opencv::core::set_num_threads

source · 
pub fn set_num_threads(nthreads: i32) -> Result<()>
Expand description

OpenCV will try to set the number of threads for subsequent parallel regions.

If threads == 1, OpenCV will disable threading optimizations and run all it’s functions sequentially. Passing threads < 0 will reset threads number to system default. The function is not thread-safe. It must not be called in parallel region or concurrent threads.

OpenCV will try to run its functions with specified threads number, but some behaviour differs from framework:

  • TBB - User-defined parallel constructions will run with the same threads number, if another is not specified. If later on user creates his own scheduler, OpenCV will use it.
  • OpenMP - No special defined behaviour.
  • Concurrency - If threads == 1, OpenCV will disable threading optimizations and run its functions sequentially.
  • GCD - Supports only values <= 0.
  • C= - No special defined behaviour.

§Parameters

  • nthreads: Number of threads used by OpenCV.

§See also

getNumThreads, getThreadNum