On 01/09/2010, Damien Doligez <damien.doli...@inria.fr> wrote: > > On 2010-08-15, at 12:45, Adrien wrote: > >> First, remove all non-tail-rec functions: no more List.map, @ or >> List.concat. All lists were pretty short (definitely less than 1000 >> elements) but maybe the amount of calls generated garbage or something >> like that: I couldn't get much infos about the problem so I tried what >> I could think of and being tail-rec couldn't be a bad thing anyway. >> The idea was to create less values since I first suspected a memory >> fragmentation issue (iirc I had thousands of fragments), so I also >> memoized some functions. > > That has nothing to do with the GC getting huge counts.
I know but I first had crashes which didn't show the huge counts and did what I had planned to do for some time. Also, I was actually generating lots of garbage (well, maybe not 10^20 ;-)). > Also, if you > have fragmentation problems, you can try changing the allocation > policy with this statement: > > Gc.set {(Gc.get ()) with Gc.allocation_policy = 1};; > > I'm still waiting for feedback on that alternate allocation policy :-) I had tried that, it didn't change anything. >> Then, as Basile mentionned, call something like Gc.compact () >> regularly. The overhead is actually pretty small, especially if ran >> regularly. > > That's good for tracking down problems, but I wouldn't recommend it > for production code. > >> Finally, C bindings. I created a few while not having access to the >> internet and they are quite dirty. I highly doubt they play perfectly >> well with the garbage collector: they seem ok but probably aren't >> perfect. That's definitely something to check, even if the bindings >> were written by someone else because working nicely with the GC can be >> quite hard. >> >> Now, the problem seems to be gone but I can't say for sure. One really >> annoying thing was that adding a line like 'print_endline "pouet";' >> would make the out-of-memory problem go away! Same when getting stats >> from the GC. > > > That almost certainly indicates a problem with your C bindings: some > pointer gets garbled and the GC may or may not stumble upon it. That's also what I think: calling Gc.compact () doesn't solve the problem, it only changes the planet alignment and the phase of the moon. Sorry for the late reaction, I was pretty short on time during the past ten days but it's going to be better now. :-) I took a quick look at the C stubs and noticed a few variables of type 'value' where not introduced with CAMLlocalX(), in particular the creation of a list. I don't know if that's enough to fix the problem since it wasn't happening anymore on my computer and I'm now waiting for someone to be able to test. -- Adrien Nader _______________________________________________ Caml-list mailing list. Subscription management: http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list Archives: http://caml.inria.fr Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs