That's an interesting point. Unfortunately, it would make my job easier (as I've already implemented a file-based mutex) and wouldn't give me the chance to learn something new.
On Thu, Feb 26, 2015 at 11:49 AM, Raul Miller <rauldmil...@gmail.com> wrote: > Unless you are using multiple machines, files are probably a better > coordination abstraction than sockets. > > (And if you are using multiple machines, you might still want to be > using a file-like abstraction.) > > The reason is that sockets give you a "stop and wait" abstraction > while files give you a "named data" abstraction. > > Also, modern OS's are pretty good about caching files, not so good > about caching stuff going across sockets. > > Thanks, > > -- > Raul > > On Thu, Feb 26, 2015 at 11:29 AM, Devon McCormick <devon...@gmail.com> > wrote: > > I run parallelized J on multi-core machines and have done so for years. > I > > looked at the "CPU affinity" thing and concluded it was a waste of time > and > > an unnecessary constraint for what I was doing. What I've found is that > > the OS - Windows in my case - does a fine job on its own of distributing > > multiple J sessions across the available cores. > > > > A detailed write-up of what I've done is here: > > > http://www.jsoftware.com/jwiki/Community/Conference2012/Talks/ParallelSimulationInJ > > . An earlier version is here: > > http://www.jsoftware.com/jwiki/DevonMcCormick/ParallelizedJCodeExamples > . > > > > The next advance I'd like to come up with would be to spin off multiple J > > processes, then co-ordinate work between them with something like > sockets. > > This would allow me to do some simple load-balancing. > > > > On Wed, Feb 25, 2015 at 9:04 PM, Joe Bogner <joebog...@gmail.com> wrote: > > > >> On Wed, Feb 25, 2015 at 5:41 PM, N.N. <nakabi...@gmail.com> wrote: > >> > >> > 1) does Windows use the 8 processors to run the j-console ? > >> > > >> > >> No, J is single threaded > >> > >> 2) is it possible to run 8 j-consoles and assign each console on one > >> > processor ? > >> > > >> > >> You could, but I'm not sure what the benefit would be. You could assign > CPU > >> affinity to each process. Each would run independently. > >> > >> 3) is it possible to use 1 console and manually create threads > >> > assigning a process on the 7 remaining processors ? > >> > > >> > > >> J is single threaded and doesn't provide a capability to create threads > >> natively. You can spawn processes so you would need to write your own > code > >> to spawn the processes and submit the work to each process. This is > >> conceptually how other single threaded console apps cluster their work > >> (node.js and R) > >> > >> I have done some prototyping on this topic: > >> > >> 1. Integrating tinyc to just-in-time compile multi-threaded C code - > >> http://www.jsoftware.com/pipermail/chat/2015-February/006488.html > >> > >> 2. Integrating go-lang to function as a multi-threaded web server - > >> http://www.jsoftware.com/pipermail/source/2015-February/000663.html > >> > >> 3. Spawning another J process and duplicating the socket to effectively > >> function as a multi-threaded server - > >> http://www.jsoftware.com/pipermail/chat/2013-August/005328.html > >> > >> > >> Still, it would be worthwhile to understand your use-case for > threading. My > >> experience has been that threading is most useful when different tasks > need > >> to run in parallel. I haven't seen as much benefit in breaking up a > single > >> task into chunks and executing it on multiple threads / processes. J's > >> performance has been largely sufficient for single task execution. > >> ---------------------------------------------------------------------- > >> For information about J forums see http://www.jsoftware.com/forums.htm > >> > > > > > > > > -- > > Devon McCormick, CFA > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- Devon McCormick, CFA ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
