[LLVMdev] Future of the LLVM OpenMP runtime

[David Chisnall]

On 27 Feb 2014, at 21:20, Rick Mann <rmann at latencyzero.com> wrote:

> I don't know, well, anything about how OpenMP is implemented. But does it make sense to use Grand Central Dispatch on platforms that support it (instead of, I assume, pthreads)?

It would certainly be interesting for an OpenMP runtime and libdispatch to use the same kernel APIs for determining system load and the number of threads that it makes sense to create.  For HPC applications, the number of threads that OpenMP should use is basically the number of cores (although not always, depending on the workload, many other disclaimers apply), but for a desktop or mobile there may be power management concerns or other higher-priority tasks that mean that you'll get better throughput using fewer threads.

David