So, it would be pretty interesting if we could have an ST s style mechanism, where the data structure is not allowed to escape. But I wonder if this would be too cumbersome for anyone to use.
Edward Excerpts from Simon Marlow's message of Fri Apr 20 06:07:20 -0400 2012: > On 19/04/2012 11:45, Herbert Valerio Riedel wrote: > > > For the time-dimension, I'm already using functions such as > > System.Timeout.timeout which I can use to make sure that even a (forced) > > pure computation doesn't require (significantly) more wall-clock time > > than I expect it to. > > Note that timeout uses wall-clock time, but you're really interested in > CPU time (presumably). If there are other threads running, then using > timeout will not do what you want. > > You could track allocation and CPU usage per thread, but note that > laziness could present a problem: if a thread evaluates a lazy > computation created by another thread, it will be charged to the thread > that evaluated it, not the thread that created it. To get around this > you would need to use the profiling system, which tracks costs > independently of lazy evaluation. > > On 19/04/2012 17:04, Herbert Valerio Riedel wrote: > > >> At least this seems easier than needing a per-computation or > >> per-IO-thread caps. > > > > How hard would per-IO-thread caps be? > > For tracking "memory use", which I think is what you're asking for, it > would be quite hard. One problem is sharing: when a data structure is > shared between multiple threads, which one should it be charged to? Both? > > To calculate the amount of memory use per thread you would need to run > the GC multiple times, once per thread, and observe how much data is > reachable. I can't think of any fundamental difficulties with doing > that, but it could be quite expensive. There might be some tricky > interactions with the reachability property of threads themselves: a > blocked thread is only reachable if the object it is blocked on is also > reachable. > > Cheers, > Simon > _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
