2017-08-19 10:42 GMT+03:00 <ilia.galas...@gmail.com>: > Thank your for explanations!! > I would like to clarify a few moments. > > If I have 4 physical cores. The optimal number of paralell workers will be > from 3 to 4 ?
The optimal number of workers depends a lot on the problem being solved. Sometimes overcommitting is good, other times sticking to the physical number of cores, or physical number of cores -1 or -2 is best (depending on the number of control threads and other contention on the system) > I want to paralell several algorithms. The performance of those alogrithms > from 5 to 7 seconds. > When I divide this algorithm to chunks and create 3 or 4 workers, I get > performance from 1.2 - 1.5 second per each chunk, but when I create more > workers performance is getting slower. >From 5-7 seconds to 1.2 - 1.5 seconds with 3-4 workers sounds like good scaling: 3.33x - 5.8x. The workers you create with emscripten_create_worker do not go away automatically, but you need to call emscripten_destroy_worker() to unload it. Creating and destroying workers for each task is not good, but it is faster to precreate a pool of workers and reuse those, and use emscripten_call_worker() to start the tasks. Creating 50 workers at the same time would be way too much, unless your system had 30-50 cores. > I create workers during startup and call them in runtime. > I noticed that first worker call takes 0.4 - 0.6 second. Next calls take > 0.05 seconds. Due to JavaScript JIT effects, it is possible to see multiple calls to emscripten_call_worker(), even with the same task, to take different amount of time. On N first calls, the JIT optimizer will pick up optimization info about the runs, and subsequent calls can become a bit faster. -- You received this message because you are subscribed to the Google Groups "emscripten-discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to emscripten-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
