Re: Unexec'ing Scwm [was Re: Proposal for a Guile binary file format]

[thi <ttn at mingle dot glug dot org>]

Greg J. Badros writes:

 > I'm not sure what you mean: "separate its guile-specific interface
 > from r4rs code"?

this is only applicable if you use the module system, i think.  in that
case, foo.scm would have

	(define-module (foo) :use-module (hobbit4d link))
	(hobbit-load-from-path 'foo-implementation)
	(export ...)

and foo-implementation.scm would have hobbit-compilable (r4rs) code
only.  the idea is similar to C programs: .h and .c files for interface
and implementation, respectively.

 > That stuff is easy enough to tweak when people agree.  I'll have to
 > look at what thud does as an example.  How much Scheme code do you
 > compile into shared libraries and how much faster is loading those
 > than loading the Scheme code directly?

currently one file (about 20 definitions) is compiled -- grep for
"simmath".  see src/thud/impl/runtime.scm for the loading, and
src/thud/impl/com.scm for the definition of `thud-load-from-path'.

fwiw, wrt load-performance, here are some numbers and comments:

 scheme-code directly:   5 ms
 using shared lib:      22         this includes one-time overhead
				   of loading (hobbit4d link) runtime
				   which is shared for all libraries
				   loaded this way.

see below for modified `thud-load-from-path'.  when i move loading of
(hobbit4d link) out of the accounting (not shown), the number is 18.

i must caution that these numbers are probably useless in determining
how things would behave for scwm, ymWv (W => will most definitely).

thi


--------------
(defmacro thud-load-from-path (file-name-snippet)
  `(let ((start (get-internal-run-time)))
     (if (string=? "" (%thud-config-info 'HOBBIT_ROOT))
	 (load-from-path (string-append ,file-name-snippet ".scm"))
	 (begin (use-modules (hobbit4d link))
		(hobbit-load-from-path ,file-name-snippet)))
     (let ((now (get-internal-run-time)))
       (say ";;;;;; start" start "now" now "diff" (- now start)))))