Thanks for the code. Gambit compares favourably to Erlang (19.2.3) both when using a 5 microsecond and 50 microsecond granularity. Here are the timings and source code files:
% gsc -exe tfib-5us.scm % time ./tfib-5us 1.69 real 10.17 user 0.14 sys % time escript tfib-5us.erl 2.13 real 11.80 user 1.51 sys % gsc -exe tfib-50us.scm % time ./tfib-50us 12.71 real 96.83 user 0.18 sys % time escript tfib-50us.erl 19.57 real 136.10 user 7.71 sys
I wonder why the system time is much higher for Erlang.
Marc
On Mar 11, 2017, at 5:08 AM, Leif Bruder leifbruder@gmail.com wrote:
Here's an Erlang version, with lots of grains of salt added: AFAIK Erlang doesn't provide bigint expt and sqrt, so they had to be added to the Erlang src. And Erlang isn't exactly known for numerical performance. With that in mind, here goes:
-module(fib). -export([main/1]). -mode(compile).
expt(_, 0) -> 1; expt(A, 1) -> A; expt(A, B) -> A * expt(A, B-1).
isqrt(Num, M, N) when abs(M - N) =< 1 -> if N * N =< Num -> N; true -> N - 1 end;
isqrt(Num, _, N) -> isqrt(Num, N, (N + Num div N) div 2).
integer_sqrt(Value) when Value >= 0 -> isqrt(Value, 1, (1 + Value) div 2).
short_delay(Value) -> integer_sqrt(Value).
range(I, J) -> lists:seq(I, J-1).
tfib(0, GV) -> short_delay(GV), 1; tfib(1, GV) -> short_delay(GV), 1; tfib(N, GV) -> short_delay(GV), Pid = self(), spawn(fun() -> Pid ! tfib(N-2, GV) end), Y = tfib(N-1, GV), receive Result -> Result + Y end.
goloop(0) -> ok; goloop(ThreadsRemaining) -> receive _ -> goloop(ThreadsRemaining - 1) end.
go(N, Repeat, Granularity) -> Pid = self(), GV = expt(11, Granularity), Threads = [spawn(fun() -> Pid ! tfib(N, GV) end) || _ <- range(0, Repeat)], goloop(length(Threads)).
main(_) -> go(15, 100, 0), go(15, 20, 1001).
$ time escript fib.erl
real 1m22.728s user 7m54.460s sys 0m0.396s
Ran on a six-core machine, Erlang used up all cores up to nearly 100%.
Leif
2017-03-11 1:45 GMT+01:00 Marc Feeley feeley@iro.umontreal.ca: I considered Ruby… but then learned that MRI only implements green threads…
Thanks for the suggestions for other languages… Perl actually supports threads? Who would have thought!
Can I ask for your help in translating the benchmark program?
The actual computation performed by the “short-delay” procedure doesn’t matter, but it should take about 50 microseconds (in order to isolate the performance related to the implementation of threads).
Marc
;;; Compute fib using threads.
(declare (standard-bindings) (fixnum) (not safe) (block))
(define big 0)
(define (granularity-set! g) (set! big (expt 11 g)))
(define (short-delay) (integer-sqrt big))
(define (tfib n) (short-delay) (if (< n 2) 1 (let* ((x (thread-start! (make-thread (lambda () (tfib (- n 2)))))) (y (tfib (- n 1)))) (+ (thread-join! x) y))))
(define (range i j) (let loop ((j (- j 1)) (lst '())) (if (< j i) lst (loop (- j 1) (cons j lst)))))
(define (go n repeat) (let ((threads (map (lambda (i) (make-thread (lambda () (tfib n)))) (range 0 repeat)))) (for-each thread-start! threads) (map thread-join! threads)))
(granularity-set! 0)
(go 15 100)
(granularity-set! 1001) ;; granularity of about 50us per thread
(go 15 20)
On Mar 10, 2017, at 7:30 PM, C K Kashyap ckkashyap@gmail.com wrote:
Super!!! Perl 5 may be a good candidate as well. Regards, Kashyap
On Fri, Mar 10, 2017 at 4:28 PM, Bradley Lucier lucier@math.purdue.edu wrote: Would a multi-threaded http server test what you want to test?
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