On Sat, Apr 9, 2011 at 7:50 PM, Matthew Flatt <mfl...@cs.utah.edu> wrote: > At Sat, 9 Apr 2011 19:00:20 -0500, Robby Findler wrote: >> On Sat, Apr 9, 2011 at 6:46 PM, <mfl...@racket-lang.org> wrote: >> > 8570033 Matthew Flatt <mfl...@racket-lang.org> 2011-04-09 17:10 >> > : >> > | futures: more bug fixes, make `touch' safe >> > | - bug fixes are related to allocation and runstack space >> > | - a `touch' within a future can complete before the `touch'ing >> > | future is itself `touch'ed >> >> Just to make sure I understand: this is only in the case that the >> touch within the future is touching some finished future or a future >> that is going to finish without being unsafe, right? > > Yes. > > If a future is touched by more than once (I doubt we have such > programs, so far), then there's a slight generalization: If the touched > future involves an unsafe operation, but it is also touched via the > runtime thread, then the touching future can run after the runtime > touch completes.
Oh, nice. > There's probably room for improvement in the scheduler. Specifically, > if a future is touched and it's far back in the queue, it might be > better to move it to the front of the queue, so that the original > future can continue sooner. > > > Meanwhile, my explorations for `touch' uncovered the real sources (I > think) of crashes on my machine yesterday: > > * Lightweight continuations were sometimes captured during an attempt > to synchronize for allocation (not useful, and not supported by the > JIT). > > * Application of a lightweight continuation needed to make sure that > the new runstack has enough extra space (i.e., the original host of > the continuation checked to make sure it had enough space, so the > new host needs to have at least as much space). > > Fixing those bugs was probably more useful than the `touch' changes. Yes, certainly! Thanks. Robby _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
