On Sun, Jul 21, 2013 at 3:32 AM, Carter Schonwald < carter.schonw...@gmail.com> wrote:
> ok, could you add those comments (about additional operations to consider) > to the ticket? > Sure. Just did that. > relatedly: if we want these atomic ops to use the sequential analogues > when we're not using the threaded run time system, does that mean > we need to have a symbol / constant variable exposed in the RTS we link > in, so that the inline code branches on a linktime constant value / symbol > (something like "isThreadedRTS:: Bool", ) or some sort of analogue > thereof? > I think it will take some care to mimic the semantics perfectly. Why not just leave the real atomic ops even in non-threaded mode, at least at first? Later we can optimize it if we find that people are using concurrent data structures heavily in non-threaded mode ;-). > one nice thing about doing such, is that if at some point link time > optimization is added, the branch would go away! On the other hand, it > could be argued that the cost of the call to the CAS primops in their > current form isn't that much more expensive than such a branch. > Indeed, I'm much more concerned about performance in the threaded case and making sure they're correct.
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