http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51617
--- Comment #4 from Dave Abrahams <dave at boostpro dot com> 2011-12-19 10:58:46 UTC --- (In reply to comment #2) > Yes, this was an intentional choice (as I described in message > c++std-lib-30840) to ensure the system doesn't get killed by a fork bomb, e.g. > writing a parallel sort algorithm using async which launches a new thread for > every partition. I tried it, it wasn't pretty :) Hey, cool; I tried it too. I mean, when I discovered async wasn't async. :-) > At some point I will use getloadavg() or equivalent functionality to check the > system load and decide whether to launch a new thread or not, until then the > safer choice is to require a user to explicitly request it (then it's the > user's fault if they fork bomb their machine!) Yeah, but in the meantime you could also just limit async() threads to hardware_concurrency() using the technique shown in my attachment. It wouldn't necessarily guarantee good performance but it would be enough to prevent async from fork bombing while still allowing some semi-intelligent amount of parallelism.
