8 Dec
2005
8 Dec
'05
5:24 a.m.
On 08 December 2005 09:40, Simon Marlow wrote:
If you share IORefs between threads and run on a multiprocessor, you are at the mercy of both sequential optimisations and your architecture's memory consistency guarantees. In other words, don't do it. Use communication primitives that have strong properties in a multi-threaded setting.
I realised this paragraph is a bit stronger than I meant. Of course it's fine to share IORefs between threads as long as you use a proper communication primitive to synchronise access to the IORef. eg. using one MVar to lock on a bunch of IORefs is perfectly fine (this is how GHC's IO library is implemented). Cheers, Simon