[racket] thread size and creation time

here the little program

#lang racket/base

(current-thread-initial-stack-size 1)

(define num-threads 10000)
(collect-garbage)
(collect-garbage)
(collect-garbage)

(define before (current-memory-use))
(displayln before)
(for ([i num-threads]) 
 (thread (lambda () 
           (sleep 100))))

(collect-garbage)
(collect-garbage)
(collect-garbage)

(define after (current-memory-use))
(displayln after)
(displayln (exact->inexact (/ (- after before) num-threads)))
(sleep 100)


On 11.05.2013, at 12:17, Berthold Bäuml <berthold.baeuml at dlr.de> wrote:

> Hi,
> 
> what is the reason that threads in Racket are so much bigger than in Gambit Scheme and take so much longer to create them? Is there possibly a way to come closer to Gambit performance or have threads in Gambit less functionality? In my little Racket test program below I get about 10kB per thread on my MacBook and creation takes about 100us per thread (Gambit claims to fit "millions of active threads in ~1GB and a creation time of 0.5us).
> 
> Marc Freely states in a talk from 2010 about Gambit http://www.iro.umontreal.ca/~gambit/Gambit-inside-out.pdf
> 
> Green threads
> Preemptive scheduler with priorities
> Very lightweight and scalable
> Thread = descriptor (324 bytes) + continuation 
> Thread creation/synchronization ~ 0.5 μs 
> O(log N) enqueue/dequeue operations 
> Supports millions of active threads (in ~ 1GB)
> 
> 
> Best,
> Berthold
> 
> -- 
> -----------------------------------------------------------------------
> Berthold Bäuml -- Head of Autonomous Learning Robots Lab
> DLR, Robotics and Mechatronics Center (RMC)
> Münchner Str. 20, D-82234 Wessling
> Phone +49 8153 282489
> http://www.robotic.de/Berthold.Baeuml
> 
> 

-- 
-----------------------------------------------------------------------
Berthold Bäuml -- Head of Autonomous Learning Robots Lab
DLR, Robotics and Mechatronics Center (RMC)
Münchner Str. 20, D-82234 Wessling
Phone +49 8153 282489
http://www.robotic.de/Berthold.Baeuml