File I/O Metrics

[Garrett Dangerfield]

Good call. Got the time down with SBCL to 3.5 seconds.  So still more than
twice Java.  ABCL with the same code with the big file (5.8G) is around
110+ seconds.

I'm still surprised by ABCL being SO much slower than SBCL especially with
Java being faster than SBCL.

Thoughts?

Thanks,
Garrett.

P.S. I also took the "time" out, I am doing SBCL/ABCL the same way as I did
in Java with the getting the start time before reading and getting the time
after reading. and calculating the duration that way.  It didn't make any
difference that I could see in the times.

Lisp code:
  (with-open-file (stream "/media/danger/OS/temp/great_expectations.iso"
 :element-type '(unsigned-byte 8)
 :external-format 'iso-8859-1) ; jars.txt iso-8859-1 also tried :default
and the time was the same
 (let ((size (file-length stream))
(buffer-size (* 16 1024 1024)) ; 16M
(start (get-internal-real-time))
)
   (loop with buffer = (make-array buffer-size :element-type
'(unsigned-byte 8))
 for n-characters = (read-sequence buffer stream)
 while (< 0 n-characters))
   (format t "took ~,2f secs" (/ (- (get-internal-real-time) start)
  internal-time-units-per-second))
   ))

On Fri, Oct 21, 2022 at 2:52 PM Pascal Bourguignon <pjb at informatimago.com>
wrote:

> Le 21/10/2022 à 23:18, Garrett Dangerfield a écrit :
> > I tried changing (make-array buffer-size :element-type 'character)
> > to
> > (make-array buffer-size :element-type 'byte)
> > and I got additional warnings and it took 70 seconds instead of 20.
> >
>
> You need to specify a binary file too!
>
> (deftype octet () '(unsigned-byte 8))
> (with-open-file (stream #P"~/Downloads/Discord.dmg"
>                          :element-type 'octet
>                          :external-format :default)
>    (print `(size = ,(file-length stream)))
>    (let ((buffer-size (* 16 1024 1024)))
>      (time
>       (loop with buffer = (make-array buffer-size :element-type 'octet)
>             for n-bytes = (read-sequence buffer stream)
>             while (plusp n-bytes)))))
>
>
>
> --
> __Pascal Bourguignon__
>
>
>
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