From: Robert Dewar <dewar@gnat.com>
Subject: Re: Apex vs GNAT on solaris
Date: 1999/12/07
Date: 1999-12-07T00:00:00+00:00 [thread overview]
Message-ID: <82hnll$ahu$1@nnrp1.deja.com> (raw)
In-Reply-To: 82hiuj$74o$1@nnrp1.deja.com
In article <82hiuj$74o$1@nnrp1.deja.com>,
reason67@my-deja.com wrote:
You need to say what options you are using for both compilers.
We have sometimes found people making the *amazing* mistake
of compiling GNAT with -O0. Generally the appropriate options
for benchmarking are -O2 -gnatn.
The options are critical, because otherwise you may simply
be measuring differences in choices of default options. For
example if one compiler inlines by default, the other one
does not, then the comparison may be meaningless.
You also need to specify all other parameters. For instance,
if you are running tasking, make sure you are comparing
comparable underlying threads implementations, otherwise you
again have apples and oranges (e.g. which of the two threads
libraries did you use for GNAT).
We often work with customers running benchmarks, and we often
find that the comparisons are meaningless for various reasons,
sometimes to the disadvantage of GNAT, sometimes to its bogus
advantage.
It is very hard to do meaningful comparison testing.
Robert Dewar
Ada Core Technologies
Sent via Deja.com http://www.deja.com/
Before you buy.
next prev parent reply other threads:[~1999-12-07 0:00 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-12-07 0:00 Apex vs GNAT on solaris reason67
1999-12-07 0:00 ` reason67
1999-12-07 0:00 ` reason67
1999-12-07 0:00 ` Robert Dewar [this message]
1999-12-07 0:00 ` Roger Racine
1999-12-07 0:00 ` Jean-Pierre Rosen
1999-12-07 0:00 ` David Starner
1999-12-08 0:00 ` Robert Dewar
1999-12-07 0:00 ` Samuel T. Harris
1999-12-07 0:00 ` Larry Kilgallen
1999-12-08 0:00 ` Robert Dewar
1999-12-08 0:00 ` Roger Racine
1999-12-08 0:00 ` Larry Kilgallen
1999-12-08 0:00 ` Roger Racine
1999-12-08 0:00 ` tmoran
1999-12-08 0:00 ` Larry Kilgallen
1999-12-09 0:00 ` Robert Dewar
1999-12-09 0:00 ` Roger Racine
1999-12-09 0:00 ` Mike Silva
1999-12-10 0:00 ` Robert Dewar
1999-12-09 0:00 ` Larry Kilgallen
1999-12-10 0:00 ` Robert Dewar
1999-12-16 0:00 ` Stefan Skoglund
1999-12-08 0:00 ` Robert A Duff
1999-12-08 0:00 ` Ted Dennison
1999-12-07 0:00 ` reason67
1999-12-08 0:00 ` Robert Dewar
1999-12-08 0:00 ` reason67
1999-12-08 0:00 ` Robert A Duff
1999-12-08 0:00 ` Robert Dewar
1999-12-08 0:00 ` Larry Kilgallen
1999-12-07 0:00 ` reason67
1999-12-07 0:00 ` reason67
1999-12-07 0:00 ` reason67
1999-12-07 0:00 ` Robert Dewar
1999-12-07 0:00 ` reason67
1999-12-07 0:00 ` reason67
1999-12-07 0:00 ` reason67
1999-12-07 0:00 ` Robert Dewar
1999-12-07 0:00 ` Vladimir Olensky
1999-12-07 0:00 ` Vladimir Olensky
1999-12-09 0:00 ` Geoff Bull
1999-12-09 0:00 ` Vladimir Olensky
1999-12-09 0:00 ` Vladimir Olensky
1999-12-10 0:00 ` Vladimir Olensky
1999-12-07 0:00 ` reason67
1999-12-08 0:00 ` Robert Dewar
1999-12-08 0:00 ` reason67
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