On Tue, Feb 17, 2009 at 10:07:05AM +0000, Sylvain Le Gall wrote: > On 17-02-2009, Rémi Dewitte <r...@gide.net> wrote: > You are using input_char and standard IO channel. This is a good choice > for non-threaded program. But in your case, I will use Unix.read with a > big buffer (32KB to 4MB) and change your program to use it. As > benchmarked by John Harrop, you are spending most of your time in > caml_enter|leave_blocking section.
This isn't quite right actually -- the profile is deceiving. It is true that there are a lot of calls to enter/leave_blocking_section, but you're actually being killed by the overhead of an independent locking strategy in the channel-based I/O calls. I've measured this using some hackery with a hex editor. When you call input_char, you acquire and then release another lock which is specific to these calls (the global runtime lock is often not released here). This process isn't especially cheap, so it would be better to use one of the other channel calls to read data in larger blocks. Mark _______________________________________________ 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
