Re: Recommended -march settings [was: Re: [gentoo-dev] CFLAGS paragraph submission for the GWN]

2006-10-14 Thread Mike Frysinger
On Saturday 14 October 2006 04:49, Sebastian Bergmann wrote:
  Do we have an official list of recommended -march settings somewhere?

  I, for one, still do not know what the right CFLAGS for my ThinkPad X60s
  with its Intel Core Duo CPU are.

but what you actually want is a list that tells you what cpu value to pass 
to -march/-mtune based upon the product name of the processor you're running

wikipedia.org is a good resource to find out the capabilities of your cpu ... 
or you could simply compare `man gcc` to /proc/cpuinfo

CFLAGS=-march=pentium-m -O2 -pipe

should work fine

  while http://gentoo-wiki.com/Safe_Cflags suggests either

CFLAGS=-march=prescott -O2 -pipe -fomit-frame-pointer

here's a good reason why gentoo-wiki is not official ... this is wrong.  the 
duo cpu's are not based on the pentium4 which is what the prescott is

CFLAGS=-march=pentium-m -msse3 -O2 -pipe -fomit-frame-pointer

there is no gcc flag at the moment for duo's which means the pentium-m 
+ -msse3 is your best bet ... the base pentium-m did not include SSE3 support 
so by simply using that -march, you do not have SSE3 enabled
-mike


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Re: Recommended -march settings [was: Re: [gentoo-dev] CFLAGS paragraph submission for the GWN]

2006-10-14 Thread Wernfried Haas
On Sat, Oct 14, 2006 at 05:16:29AM -0400, Mike Frysinger wrote:
 On Saturday 14 October 2006 04:49, Sebastian Bergmann wrote:
   Do we have an official list of recommended -march settings somewhere?
 [..]
 but what you actually want is a list that tells you what cpu value to pass 
 to -march/-mtune based upon the product name of the processor you're running

What about creating an official document for both -march/mtune and
CFLAGS settings for different CPUs? If some other people like the idea
and no one else volunteers i can go poke the different arch teams,
toolchain folks and whoever else may be involved about it and compile
a list based on their input.

I wouldn't try to make it a ricer issue but rather a list of flags
that are known to be sane and supported by Gentoo.

cheers,
Wernfried

-- 
Wernfried Haas (amne) - amne at gentoo dot org
Gentoo Forums: http://forums.gentoo.org
IRC: #gentoo-forums on freenode - email: forum-mods at gentoo dot org


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Re: Recommended -march settings [was: Re: [gentoo-dev] CFLAGS paragraph submission for the GWN]

2006-10-14 Thread Simon Stelling

Wernfried Haas wrote:

What about creating an official document for both -march/mtune and
CFLAGS settings for different CPUs? If some other people like the idea
and no one else volunteers i can go poke the different arch teams,
toolchain folks and whoever else may be involved about it and compile
a list based on their input.


Check out these packages [1] before doing that, they will probably 
supply all you need.


[1] http://packages.gentoo.org/search/?sstring=cpuinfo

--
Kind Regards,

Simon Stelling
Gentoo/AMD64 developer
--
gentoo-dev@gentoo.org mailing list



Re: Recommended -march settings [was: Re: [gentoo-dev] CFLAGS paragraph submission for the GWN]

2006-10-14 Thread Christian Heim
On Saturday, 14. October. 2006 11:46, Wernfried Haas wrote:
 On Sat, Oct 14, 2006 at 05:16:29AM -0400, Mike Frysinger wrote:
  On Saturday 14 October 2006 04:49, Sebastian Bergmann wrote:
Do we have an official list of recommended -march settings somewhere?
 
  [..]
  but what you actually want is a list that tells you what cpu value to
  pass to -march/-mtune based upon the product name of the processor you're
  running

 What about creating an official document for both -march/mtune and
 CFLAGS settings for different CPUs? If some other people like the idea
 and no one else volunteers i can go poke the different arch teams,
 toolchain folks and whoever else may be involved about it and compile
 a list based on their input.

I would really like that, I've searched for such a list some times in the past 
and the closest I could come up with is freehackers.orgĀ¹ and the cflags.sh 
script in the forums.

TIA, Christian

[1] http://www.freehackers.org/gentoo/gccflags/

-- 
Christian Heim phreak at gentoo.org
GPG key ID: 9A9F68E6
Fingerprint: AEC4 87B8 32B8 4922 B3A9 DF79 CAE3 556F 9A9F 68E6


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Re: Recommended -march settings [was: Re: [gentoo-dev] CFLAGS paragraph submission for the GWN]

2006-10-14 Thread Mike Frysinger
On Saturday 14 October 2006 05:46, Wernfried Haas wrote:
 What about creating an official document for both -march/mtune and
 CFLAGS settings for different CPUs?

last i checked they're all supported
-mike


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