Re: [Vala] Fwd: Why is Vala 10 times slower than C ?

[Serge Hulne <serge hulne gmail com>]

Actually, what I do not grasp is the following:

- Vala is allegedly just a thin object-oriented layer on top of C (glib2).

-  One might therefore expect a runtime performance which is closer to
say C or C++, than to the (slower) performance of a high-level
language (like , e.g.Python).

- However, it turns out that, surprisingly Vala is not only slower
than C and C++ but even slower than Python.

This is the part that I do not understand !

Serge.




On Mon, Jun 6, 2011 at 3:21 PM, Гаврилов Максим <ulltor gmail com> wrote:
> Why do you call it an equivalent version if there's no sign of Glib, garbage
> collection, etc. in this code?
>
> Just write a Glib-based wc in C, and it will be as fast as in Vala.
>
> 06.06.2011 17:07 пользователь "Serge Hulne" <serge hulne gmail com> написал:
> > Nope !
> >
> > Here is the equivalent version in C:
> >
> > #include <stdio.h>
> >
> > #include <stdlib.h>
> >
> > #include <string.h>
> >
> > int main(int argc, char** argv)
> >
> > {
> >
> > FILE *fp = NULL;
> >
> > char buff[100], *fileName = NULL;
> >
> > int wcnt = 0;
> >
> > int lcnt = 0;
> >
> > if (argc <2)
> >
> > {
> >
> > fprintf(stderr, "Usage: wc <file_name>\n");
> >
> > exit(1);
> >
> > }
> >
> > fileName = argv[1];
> >
> > if ( (fp = fopen(fileName, "r")) == NULL)
> >
> > {
> >
> > perror(fileName);
> >
> > exit(1);
> >
> > }
> >
> > while (!feof(fp))
> >
> > {
> >
> > buff[0] = '\0';
> >
> > fgets(buff, sizeof buff/sizeof(char), fp);
> >
> > lcnt++;
> >
> > char * str = malloc(sizeof(char)*101);
> >
> > strcpy(str, buff);
> >
> > char * pch;
> >
> > pch = strtok (buff," ");
> >
> > while (pch != NULL)
> >
> > {
> >
> > //printf ("%s\n",pch);
> >
> > pch = strtok (NULL, " ");
> >
> > wcnt++;
> >
> > }
> >
> > }
> >
> > fclose(fp);
> >
> > printf("word count: %i words, lines = %d\n", wcnt, lcnt);
> >
> > return 0;
> >
> > }
> >
> >
> >
> > Serge.
> >
> >
> >
> > ---------- Forwarded message ----------
> > From: Qball Cow <qball aggervaccae nl>
> > Date: Mon, Jun 6, 2011 at 2:15 PM
> > Subject: Re: [Vala] Why is Vala 10 times slower than C ?
> > To: Serge Hulne <serge hulne gmail com>
> > Cc: vala-list gnome org
> >
> >
> > This is not really a fair comparison. Try writing the same code as you
> > wrote
> > in vala in C and then compare.
> >
> > You are now comparing a probably very highly optimized 'wc' with a naïve
> > implementation in vala.
> >
> >
> >
> > On Mon Jun 6 14:12:37 2011, Serge Hulne wrote:
> >
> > > I used "wordcount" as a test to compare the processing speed of Vala
> > > against
> > > C:
> > >
> > >
> > > I obtained the following result:
> > >
> > > ---
> > > C:
> > > ---
> > > serge:vala serge2$ time wc ../shakespeare.txt
> > > 495200 2703240 15862370 ../shakespeare.txt
> > >
> > > real 0m0.194s
> > > user 0m0.176s
> > > sys 0m0.015s
> > >
> > > ---
> > > Vala:
> > > ---
> > > serge:vala serge2$ time ./hello
> > > lc = 495201. wc = 3170980
> > >
> > > real 0m2.258s
> > > user 0m2.223s
> > > sys 0m0.028s
> > >
> > >
> > > -------
> > >
> > > The vala code is as follows:
> > >
> > > class HelloWorld : GLib.Object {
> > > public static int main(string[] args) {
> > >
> > > var f = FileStream.open("../shakespeare.txt", "r");
> > > var line = "";
> > > var wc = 0;
> > > var lc = 0;
> > >
> > > while (!f.eof()) {
> > > line = f.read_line(); lc++;
> > > if (line == null) break;
> > > //stdout.printf("line = %s\n", line);
> > > var words = line.split(" ");
> > > for (int i=0; i<words.length; i++) {
> > > //stdout.printf("word = %s\n", words[i]);
> > > wc++;
> > > }
> > > }
> > >
> > > stdout.printf("lc = %d. wc = %d\n", lc, wc);
> > > return 0;
> > > }
> > > }
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > vala-list mailing list
> > > vala-list gnome org
> > > http://mail.gnome.org/mailman/listinfo/vala-list