[gentoo-dev] [ANN] CFLAGS Builder

[gentoo-dev] [ANN] CFLAGS Builder

[Robin H.Johnson]

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Greetings,

Just a quick announcement about a new mini-project to write a little
application to work out the correct stable CFLAGS for your system from
/proc/cpuinfo and a few other sources of information.

Please visit this webpage and fill in the form.
http://gentoo.slinky.surrey.sfu.ca/cflagcollect/

For the moment, I am collecting some information so that the application
will work on ALL systems, including those with unusual configurations. 
For this to work, I would like everybody to go to the webpage, and fill
it in for all of your systems. There is a perl script on the page if you
want to automate the process more. You can run the script as
'./submit.pl EMAILADDRESS'.

If I get enough data, In a week or two I hope to have the initial
testing release of the CFLAGS builder available.

-- 
Robin Hugh Johnson
E-Mail     : robbat2@orbis-terrarum.net
Home Page  : http://www.orbis-terrarum.net/?l=people.robbat2
ICQ#       : 30269588 or 41961639
GnuPG FP   : 11AC BA4F 4778 E3F6 E4ED  F38E B27B 944E 3488 4E85

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Re: [gentoo-dev] [ANN] CFLAGS Builder

[Alec Berryman]

Robin H.Johnson said:
> Just a quick announcement about a new mini-project to write a little
> application to work out the correct stable CFLAGS for your system from
> /proc/cpuinfo and a few other sources of information.


This (http://forums.gentoo.org/viewtopic.php?t=53602) was posted in the
Gentoo forums a few days ago.  Might help you out - works great for me.

- Alec Berryman


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Re: [gentoo-dev] [ANN] CFLAGS Builder

[Kevin Hayes]

On Sun, 18 May 2003 11:16:34 -0500 (CDT)
"Alec Berryman" <alec@lorax.wox.org> wrote:

> Robin H.Johnson said:
> > Just a quick announcement about a new mini-project to write a little
> > application to work out the correct stable CFLAGS for your system from
> > /proc/cpuinfo and a few other sources of information.
> 
> 
> This (http://forums.gentoo.org/viewtopic.php?t=53602) was posted in the
> Gentoo forums a few days ago.  Might help you out - works great for me.
> 
> - Alec Berryman

Excellent idea, but unfortunately it doesn't seem to detect dual athlons on this m/c correctly.

Output is :
~ $ ./wflags 
 -march=athlon-xp -mfpmath=sse -msse -mmmx -m3dnow

 Info in /proc/cpuinfo is correct.
eg model name      : AMD Athlon(TM) MP 1800+   


--
Kevin Hayes

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Re: [gentoo-dev] [ANN] CFLAGS Builder

[Paul de Vrieze]

Kevin Hayes said:
>
> Output is :
> ~ $ ./wflags
>  -march=athlon-xp -mfpmath=sse -msse -mmmx -m3dnow
>
>  Info in /proc/cpuinfo is correct.
> eg model name      : AMD Athlon(TM) MP 1800+
>

I see that this application also does not include the -mcpu flag. I know
that -march implies the -mcpu flag. Some ebuilds however filter the -march
flag for gcc bugs. For those ebuilds the -mcpu flag still provides the
wanted scheduling

Paul

-- 
Paul de Vrieze
Researcher
Mail: pauldv@cs.kun.nl
Homepage: http://www.devrieze.net




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Re: [gentoo-dev] [ANN] CFLAGS Builder

[David Nielsen]

The -mcpu flag is depricated in GCC 3.3 - and should not be used
anymore. So in all fairness it would be best not to record it's usage,
it might mislead some users.

Regards,

On Mon, 2003-05-19 at 10:13, Paul de Vrieze wrote:
> Kevin Hayes said:
> >
> > Output is :
> > ~ $ ./wflags
> >  -march=athlon-xp -mfpmath=sse -msse -mmmx -m3dnow
> >
> >  Info in /proc/cpuinfo is correct.
> > eg model name      : AMD Athlon(TM) MP 1800+
> >
> 
> I see that this application also does not include the -mcpu flag. I know
> that -march implies the -mcpu flag. Some ebuilds however filter the -march
> flag for gcc bugs. For those ebuilds the -mcpu flag still provides the
> wanted scheduling
> 
> Paul


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Re: [gentoo-dev] [ANN] CFLAGS Builder

[Paul de Vrieze]

David Nielsen said:
> The -mcpu flag is depricated in GCC 3.3 - and should not be used
anymore. So in all fairness it would be best not to record it's usage,
it might mislead some users.

The only depreciation I could find concerning mcpu is in the mips port,
where it might not me appropriate. For x86 architectures it is available
though and it also serves a needed option as it determines instruction
scheduling. The march option does not, the march option determines which
instructions are used. As scheduling for an architecture lower than the
instructions is pointless implying mcpu makes sense. It is perfectly legal
though to specify
CFLAGS="-march=pentium -mcpu=pentium4" This would create code that runs on
anything bigger than a pentium, but is optimally scheduled for the
pentium4 processor. Scheduling has become increasingly important with the
newer (pentium and further) processors as they have the ability to run
some (but not all) instructions paralel to eachother. A p4 though provides
more pipelines than a p1, so instructions need to be scheduled differently
to optimally use all pipelines.

Paul

-- 
Paul de Vrieze
Researcher
Mail: pauldv@cs.kun.nl
Homepage: http://www.devrieze.net


-- 
Paul de Vrieze
Researcher
Mail: pauldv@cs.kun.nl
Homepage: http://www.devrieze.net




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