From: Simon Wright <simon@pushface.org>
Subject: Re: Interfacing Ada multidimensional arrays with Fortran.
Date: Sat, 28 May 2011 17:45:59 +0100
Date: 2011-05-28T17:45:59+01:00 [thread overview]
Message-ID: <m2pqn26aew.fsf@pushface.org> (raw)
In-Reply-To: m2tycf5fh4.fsf@pushface.org
Simon Wright <simon@pushface.org> writes:
>> What are the performance issues by using the three possibilities
>> above ? (may be the community already had some interesting information
>> about this)
>
> I haven't measured this. Anyone else?
On Mac OS X, using GCC 4.6.0, with -O1, applying
System.Generic_Array_Operations.Transpose 10 times to a 100x100 matrix
took 900 us, whereas using assignment with convention Fortran took 90
us.
With -O2, the assignment was hoisted out of the loop.
I then made the target matrices volatile; the results are now
-O1:
Transposition: 1200 us
Assignment: 300 us
-O2:
Transposition: 500 us
Assignment: 300 us
next prev parent reply other threads:[~2011-05-28 16:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-27 20:50 Interfacing Ada multidimensional arrays with Fortran David Sauvage
2011-05-28 9:41 ` Simon Wright
2011-05-28 16:45 ` Simon Wright [this message]
2011-06-09 7:55 ` David Sauvage
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