2009/7/15 Simon Marlow
On 15/07/2009 05:16, Brandon S. Allbery KF8NH wrote:
Reduce this to 1024, otherwise the runtime will eventually find itself
dealing with file descriptors beyond the select() limit mentioned above. Someone with more knowledge of the Haskell runtime will have to advise as to possible ways around it if you really need more than 1024 file descriptors.
There's no easy workaround. We could have the IO library switch to using blocking read() calls for the out-of-range FDs to avoid the error from the IO manager, but that is likely to lead to a different problem: too many OS threads.
The right fix is to move to using epoll() instead. I understand it is being worked on, but I don't know the current status (Johan?).
I have a standalone (i.e. not integrated into the RTS yet) proof of concept working using kqueue. However, to be portable we still need to fall back to select on systems that don't support anything better. This implies that if you want to write portable code you still suffer from this limit. I've been unable to hack lately due to an injury but I'll be able to get back to it next week. - Johan