Re: [Valgrind-users] Preliminary little speedup patch (seen 7% speedup)

[Christian L. <chr...@le...>]

On Mon, Mar 17, 2003 at 12:37:52PM +0000, Nicholas Nethercote wrote:

> 1. Can you try it with a few other programs?  It would be nice to see if
> the 7% speedup is consistent across programs.  Some programs I've used
> for performance timing in the past:
> 
>    gzip
>    bzip2

48.36user 0.05system 0:49.79elapsed 97%CPU (0avgtext+0avgdata
0maxresident)k
48.47user 0.07system 0:51.22elapsed 94%CPU (0avgtext+0avgdata
0maxresident)k

patched:
47.93user 0.09system 0:49.17elapsed 97%CPU (0avgtext+0avgdata
0maxresident)k
47.91user 0.09system 0:49.22elapsed 97%CPU (0avgtext+0avgdata
0maxresident)k

>    latex

real    0m5.088s
user    0m4.790s
sys     0m0.130s

patched:
real    0m4.741s
user    0m4.490s
sys     0m0.140s

>    konqueror (startup then quit immediately)

It eats up all CPU till it -9 kill it when I quit it.
(I still have KDE 2.2)

> 2. The bottom of the webpage you mention says:
> 
>    "An alternate way to write the above example is
> 
>    static const int array[] = { &&foo - &&foo, &&bar - &&foo,
>                                 &&hack - &&foo };
>    goto *(&&foo + array[i]);
> 
>    This is more friendly to code living in shared libraries, as it reduces
>    the number of dynamic relocations that are needed, and by consequence,
>    allows the data to be read-only."
> 
> Valgrind is packaged as a shared library.  Perhaps this might improve
> things further?

Yes, but initially I did not get it working, was a little stupid error.
I'll try it, but this takes some time.

cachegrind shows me with a little test programm, that it's slower with
the later thing. But it's not a shared library and I don't know how
often it has to be done.


Regards,
Christian Leber

-- 
  "Omnis enim res, quae dando non deficit, dum habetur et non datur,
   nondum habetur, quomodo habenda est."       (Aurelius Augustinus)
  Translation: <http://gnuhh.org/work/fsf-europe/augustinus.html>