I'm building a 3rd party c++ lib in emscripten that uses pthreads, and I'm finding that I have to use -sPTHREAD_POOL_SIZE=23 for it to work, otherwise it hangs.
I did think leaving out -sPTHREAD_POOL_SIZE (or setting it to 0) would create threads on demand, but I just found this on the emscripten pthreads docs page and suspect this is what's happening as the lib's API is just a single function that appears to execute synchronously: "you cannot call pthread_create and then keep running code synchronously that expects the worker to start running" So OK, I'll need to manually specify a pool size, but what value should I use? The lib bases it's thread usage on std::thread::hardware_concurrency() (and seems to be a bit off as I have 16 but need a pool size of 23) but I can't know that at link time so what should I use? I'll also need to hard code this as a maximum into the lib of course but that's OK. Is there a way to determine PTHREAD_POOL_SIZE at runtime? Can I just use 256 or something crazy, or would that break on some low specced computers, ie: how 'heavyweight' are these WebWorkers? I'm sort of feeling an '8' here for some reason... One other thing, what exactly does -sPTHREAD_POOL_SIZE_STRICT do? I'm finding setting it to '0' causes my app to hang if I haven't set thread pool size high enough, and setting it to '2' causes an exception to be thrown instead. So I've just set it to '2', but am I missing something with '0'? Are there any other useful values? Note that there's nothing about -sPTHREAD_POOL_SIZE_STRICT on the emscripten pthreads docs page. Finally, the lib makes quite complex use of threads - there are std::futures and std::promises all over the place and I initally thought I'd never get it going in emscripten, but once I found the PTHREAD_POOL_SIZE fix everything just worked! This is a very impressive achievement for emscripten IMO! Bye! Mark -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/emscripten-discuss/db07f3cc-0080-4c1f-946c-d57a3fef4cd5n%40googlegroups.com.
