From: Richard Guenther <richard.guenther@gmail.com>
To: Corey Kasten <corey@materialintelligencellc.com>
Cc: Nathan Froyd <froydnj@codesourcery.com>, gcc@gcc.gnu.org
Subject: Re: Better performance on older version of GCC
Date: Fri, 27 Aug 2010 15:40:00 -0000 [thread overview]
Message-ID: <AANLkTi=SeHRG=-uDU1PmYY=h8Hztmpw8UeqKLMUdtPtr@mail.gmail.com> (raw)
In-Reply-To: <1282921326.2931.17.camel@MILLC-COREY>
On Fri, Aug 27, 2010 at 5:02 PM, Corey Kasten
<corey@materialintelligencellc.com> wrote:
> On Fri, 2010-08-27 at 06:50 -0700, Nathan Froyd wrote:
>> On Fri, Aug 27, 2010 at 09:44:25AM -0400, Corey Kasten wrote:
>> > I find that the executable compiled on system A runs faster (on both
>> > systems) than the executable compiled on system B (on both system), by a
>> > factor about approximately 4 times. I have attempted to play with the
>> > GCC optimizer flags and have not been able to get System B (with the
>> > later GCC version) to compile code with any better performance. Could
>> > someone please help figure this out?
>>
>> It's almost impossible to tell what's going on without an actual
>> testcase. You might not be able to provide the actual code, but you
>> could try distilling it down to something you could release.
>>
>> -Nathan
>
> Thanks for the reply Nathan.
>
> I have attached an archive with the test case code. The code is built by
> build.sh and outputs the number of microseconds to complete the
> processing.
>
> Compiling with GCC version "4.1.2 20070925 (Red Hat 4.1.2-33)" produces
> code that runs in about 66% of the time than does GCC version "4.3.0
> 20080428 (Red Hat 4.3.0-8)"
-fcx-limited-range or -fcx-fortran-rules. 4.3 now is more conforming than 4.1.
Richard.
> Thanks
>
> Corey
>
next prev parent reply other threads:[~2010-08-27 15:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-27 13:50 Corey Kasten
2010-08-27 14:20 ` H.J. Lu
2010-08-27 14:23 ` Nathan Froyd
2010-08-27 15:03 ` Corey Kasten
2010-08-27 15:40 ` Richard Guenther [this message]
2010-08-27 16:29 ` Corey Kasten
2010-08-28 1:06 ` Xinliang David Li
2010-08-28 8:23 ` Andrew Pinski
2010-08-28 10:08 ` Xinliang David Li
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