]> Hello, To compare different implementations of a function I would like to profile its execution in time and heap memory usage (at least orders of magnitude). To do so, I use the code below, relying on the Gc and Unix libraries. I have the following questions : 1) When I start profiling should I prefer a Gc.compact to Gc.full_major ? 2) Unix.times seems to have a low resolution, which means that my timings are often 0.0 (unless I execute the function a lot of times). I don't want to use Unix.gettimeofday because this prevents me to make the difference between user and system time. Has anybody bindings to the getrusage function or another idea ? 3) What is the accuracy of these results ? E.g. I read in the documentation of the Gc module that the field minor_words is only an approximation in programs compiled to native code. Is it also true for the other fields ? How much can I trust the figures I get ? 4) Is it possible to know at runtime whether we are running native code or interpreted bytecode ? Thanks for your answers, Daniel -- profile.ml -- type t = { minor_bytes : float; promoted_bytes : float; major_bytes : float; allocated_bytes : float; minor_collections : float; major_collections : float; user_time : float; system_time : float } (* Bytes per words *) let bpw = float_of_int (Sys.word_size / 8) (* Heap allocation overhead due to profiling *) let heap_overhead = let s = Gc.stat() in ignore(Unix.times()); ignore(Unix.times()); let s' = Gc.stat() in ((s'.Gc.minor_words +. s'.Gc.major_words -. s'.Gc.promoted_words) -. (s.Gc.minor_words +. s.Gc.major_words -. s.Gc.promoted_words)) *. bpw let execution_mean (f : 'a -> 'b) (arg : 'a) n = Gc.full_major (); let s = Gc.stat () in let t = Unix.times () in for i = 1 to n do ignore(f arg) done; let t' = Unix.times () in let s' = Gc.stat () in let mi, pro, ma = ((s'.Gc.minor_words -. s.Gc.minor_words) *. bpw) -. heap_overhead, (s'.Gc.promoted_words -. s.Gc.promoted_words) *. bpw, (s'.Gc.major_words -. s.Gc.major_words) *. bpw in let n' = float_of_int n in { minor_bytes = mi /. n'; promoted_bytes = pro /. n'; major_bytes = ma /. n'; allocated_bytes = (mi +. ma -. pro) /. n'; minor_collections = (float_of_int (s'.Gc.minor_collections - s.Gc.minor_collections)) /. n'; major_collections = (float_of_int (s'.Gc.major_collections - s.Gc.major_collections)) /. n'; user_time = (t'.Unix.tms_utime -. t.Unix.tms_utime) /. n'; system_time = (t'.Unix.tms_stime -. t.Unix.tms_stime) /. n' } let execution (f : 'a -> 'b) (arg : 'a) = execution_mean f arg 10_000 ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners