The biggest problem with pmap I have is ordering, ie. it will process in batches of (+ 2 (.. Runtime getRuntime availableProcessors)), and only take a new batch when the slowest of the old batch has been evaluated. With functions dependent on IO, parallel gains are only a fraction of what they could be. I used to solve this by creating my own code to process in futures and delays, but when I found the claypoole library, especially it's unordered pmap and for, I never had to touch these again.
On Wednesday, April 6, 2016 at 3:11:52 PM UTC+2, Mars0i wrote: > > Maybe people forget about pmap <http://clojuredocs.org/clojure.core/pmap>, > pcalls <http://clojuredocs.org/clojure.core/pcalls>, and pvalues > <http://clojuredocs.org/clojure.core/pvalues> because they're just too > easy. > > On Tuesday, April 5, 2016 at 8:51:59 PM UTC-5, tbc++ wrote: >> >> If it all seems confusing, do not despair, there's two things that will >> handle the vast majority of the use cases you may have: >> >> 1) `future` - spawns a thread that runs the body of the future ( >> https://clojuredocs.org/clojure.core/future) >> 2) `atom` and `swap!` - Used to store data that needs to be shared >> between threads and updated concurrently ( >> https://clojuredocs.org/clojure.core/atom) these are built on top of >> CAS, which itself is foundation upon which most of concurrent programming >> is built. (https://en.wikipedia.org/wiki/Compare-and-swap) >> >> Those two primitives alone will handle 90% of the use cases you will run >> into as a new clojure developer. The rest of the stuff (agents, thread >> pools, refs, vars, cps/core.async) can all come in time, but you will use >> them much less often than threads and atoms. So read up on those two and >> feel free to come back with any questions you may have. >> >> Timothy >> >> >> On Tue, Apr 5, 2016 at 7:24 PM, Chris White <cwpr...@live.com> wrote: >> >>> I was doing some reading of code recently to help me get up to speed >>> with Clojure. One of the libraries I randomly came across dealt with >>> parallelism and I had a hard time following along with it. To try and wrap >>> my head around things I did a quick search and found this article: >>> >>> >>> http://www.thattommyhall.com/2014/02/24/concurrency-and-parallelism-in-clojure/ >>> >>> I'm not sure how authoritative this is based on my current experience, >>> but needless to say I was a bit overwhelmed. That said is there any sort of >>> introductory material that list members have used to help get them into how >>> Clojure deals with concurrency and parallelism? I also don't mind anything >>> that's not specifically using Clojure but will at least help me understand >>> the concepts behind how Clojure does it. Thanks again for any and all help! >>> >>> - Chris White (@cwgem) >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Clojure" group. >>> To post to this group, send email to clo...@googlegroups.com >>> Note that posts from new members are moderated - please be patient with >>> your first post. >>> To unsubscribe from this group, send email to >>> clojure+u...@googlegroups.com >>> For more options, visit this group at >>> http://groups.google.com/group/clojure?hl=en >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "Clojure" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to clojure+u...@googlegroups.com. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> >> >> -- >> “One of the main causes of the fall of the Roman Empire was that–lacking >> zero–they had no way to indicate successful termination of their C >> programs.” >> (Robert Firth) >> > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
