Issue #11817 has been updated by matz (Yukihiro Matsumoto). Status changed from Open to Closed Thank you for bringing a concrete use case. For I/O-bound work like yours, this already works today: ```ruby results = items.map { |item| Thread.new { process(item) } }.map(&:value) ``` Beyond that, a built-in method has to decide the things @rkh listed: which execution unit to use, how many run at once, and what happens to the others when one fails. I don't see a single answer that fits everyone, so for now I think this belongs to gems such as `async`, `concurrent-ruby` or `parallel`. Matz. ---------------------------------------- Feature #11817: map.parallel https://bugs.ruby-lang.org/issues/11817#change-119364 * Author: eike.rb (Eike Dierks) * Status: Closed ---------------------------------------- I'd like to suggest a new method: #parallel That method should take care of executing workloads in parallel across multiple cores. I believe that #map can sometimes be distributed to many simultaneous threads. So we would spread out the map blocks into parallel processing, and then collect the results in order. I believe this would need some new infrastructure like apple did with great_central, so I'm talking along these lines. (Aka we only want to open up as many threads as there are cores) This would not help much with a simple map (because we need to collect and serialize the results in the end) but it could be cool for more complex mappings. Maybe this should have been a rails topic first, because there it might make a lot of sense to render partials in parallel, this could really speed up rails response rendering ;-) But I believe this is a topic for ruby in general. Given that we now go to really many cores, it should be at the heart of ruby to use that. For a start we could just declare #parallel as -> return self. and than improve on it. A naive implementation would just open a new thread for every parallel map block, but that would not work well -- it actually would be very slow. So we actually need a thread management, along the lines of great central. I believe this should be built into the very core libs of the ruby language. I know this is hard stuff, but it needs to be done. Let's go parallel from the heart of the language. --- Please let us discuss if adding the #parallel method would be a good idea. Let's come up with some implementations to find the problems. I'm explicitly referring to map#parallel here. In rails that might be cache.parallel (if you followed) for some math tasks it might also be parallel do {} -- https://bugs.ruby-lang.org/