It would be nice, I imagine, if we eventually had a mechanism like https://www.cprogramming.com/snippets/source-code/find-the-number-of-cpu-cores-for-windows-mac-or-linux
to set up a default number of threads. -- Raul On Sat, Apr 9, 2022 at 3:04 PM Henry Rich <henryhr...@gmail.com> wrote: > > The big news in J904 is multithreading. J verbs can now be run in > different cores, sharing the J global namespaces. > > [A version of J with limited support for multithreading was revealed > last year by John Ference of Monument AI. John's work was an important > proof of concept, but the J904 version is an independent development > using pthreads instead of OpenMP. John has agreed with Jsoftware to > give Jsoftware access to the code and testcases used in his work. We > have not used the code.] > > Two primitives support multithreading: > > (0 T. '') creates a thread on a new core. A thread running a verb is > called a /task/. Even if you don't plan to create tasks, you should > create threads to allow JE to use them for its own purposes. > > ([x] u t. '' y) executes ([x] <@:u y) as a task to produce a boxed > result. The thread that executed t. continues to run. But the result > is a special kind of box called a /pyx/. > > ['pyx' is Greek for box, and has been brought into English on occasion > when a word has been needed for a special box. The most recent such > borrowing until now is for the box used by the Royal Mint to hold coins > for assay.] > > A pyx looks on the outside like any other box. You can pass it as an > argument. But as soon as you look inside it, your thread is blocked > until the task producing the pyx's value has completed. Then you see the > value, and your thread continues. > > Tasks share the global namespaces and thus can freely read, write, stomp > on, and delete names visible to other tasks. > > We encourage you to experiment with threads and tasks. We are sure that > a layer of synchronizing primitives - semaphores, locks, and mutexes - > will be needed, but we would like to get practical experience with tasks > before we implement them. Suggestions welcome. > > Henry Rich > > > > > > > -- > This email has been checked for viruses by AVG. > https://www.avg.com > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
