[gentoo-user] CFLAGS

[gentoo-user] CFLAGS

[Cahn Roger]

Hi,

I'll have soon a new PC with  Processor
Intel Core2 Duo E6850
Which cflags do I need for it?
Thank you very much.
Roger
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Re: [gentoo-user] CFLAGS

[Kenneth Prugh]

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On Wed, 16 Jan 2008 20:48:21 +0100
Cahn Roger <rcahn@club-internet.fr> wrote:

> Hi,
> 
> I'll have soon a new PC with  Processor
> Intel Core2 Duo E6850
> Which cflags do I need for it?
> Thank you very much.
> Roger

CFLAGS="-O2 -march=nocona -pipe"

should do it if your running stable AMD64. If you happened to use
gcc-4.2 or later on AMD64 you could do something like this:

CFLAGS="-O2 -march=native -mtune=native -pipe"

-- 
Ken69267
Gentoo AMD64 AT

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Re: [gentoo-user] CFLAGS

[Michal 'vorner' Vaner]

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Hello

On Wed, Jan 16, 2008 at 02:54:42PM -0500, Kenneth Prugh wrote:
> CFLAGS="-O2 -march=native -mtune=native -pipe"

Could this happen a default in clean installation/manual sometime? Most
people could leave this lake it is and never think about what flags to
use.

-- 
Please stay calm. There is no use both of us being hysterical.

Michal 'vorner' Vaner

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Re: [gentoo-user] CFLAGS

[Kenneth Prugh]

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On Wed, 16 Jan 2008 21:04:11 +0100
Michal 'vorner' Vaner <vorner@ucw.cz> wrote:

> Hello
> 
> On Wed, Jan 16, 2008 at 02:54:42PM -0500, Kenneth Prugh wrote:
> > CFLAGS="-O2 -march=native -mtune=native -pipe"
> 
> Could this happen a default in clean installation/manual sometime?
> Most people could leave this lake it is and never think about what
> flags to use.
> 

I suppose if gcc 4.2 ever goes stable it could... Or if you
tell people to keyword gcc right away to 4.2 and emerge it, change the
cflags to native, then emerge -e world it would. (Not very ideal and
it's time consuming...)

(I could be wrong though...)

-- 
Ken69267
Gentoo AMD64 AT

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Re: [gentoo-user] CFLAGS

[Benedikt Morbach]

On 1/16/08, Kenneth Prugh <ken69267@gmail.com> wrote:
> CFLAGS="-O2 -march=native -mtune=native -pipe"

CFLAGS="-O2 -march=native -pipe"
would be sufficient.

On my system, it gives me (I have a core 2 duo)
CFLAGS="-O2 -march=nocona -mtune=generic -pipe"
while with gcc-4.3, I get
CFLAGS="-O2 -march=core2 -mtune=core2 -pipe"

So -march=native handles both, -march and -mtune
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Re: [gentoo-user] CFLAGS

[Peter Humphrey]

On Wednesday 16 January 2008 19:54:42 Kenneth Prugh wrote:
> On Wed, 16 Jan 2008 20:48:21 +0100
>
> Cahn Roger <rcahn@club-internet.fr> wrote:
> > Hi,
> >
> > I'll have soon a new PC with  Processor
> > Intel Core2 Duo E6850
> > Which cflags do I need for it?
> > Thank you very much.
> > Roger
>
> CFLAGS="-O2 -march=nocona -pipe"
>
> should do it if your running stable AMD64. If you happened to use
> gcc-4.2 or later on AMD64 you could do something like this:
>
> CFLAGS="-O2 -march=native -mtune=native -pipe"

Just a tiny hijack :-)

My new laptop will have a T7100 CPU. I'd like to know what CFLAGS to use, 
but even before that should I use an AMD64 or IA64 installation medium?

-- 
Rgds
Peter
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Re: [gentoo-user] CFLAGS

[Tomas Papan]

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hello,

in case that you want use 64bit system chose amd64 and -march=nocona

BR
tomas

Peter Humphrey wrote:
> On Wednesday 16 January 2008 19:54:42 Kenneth Prugh wrote:
>   
>> On Wed, 16 Jan 2008 20:48:21 +0100
>>
>> Cahn Roger <rcahn@club-internet.fr> wrote:
>>     
>>> Hi,
>>>
>>> I'll have soon a new PC with  Processor
>>> Intel Core2 Duo E6850
>>> Which cflags do I need for it?
>>> Thank you very much.
>>> Roger
>>>       
>> CFLAGS="-O2 -march=nocona -pipe"
>>
>> should do it if your running stable AMD64. If you happened to use
>> gcc-4.2 or later on AMD64 you could do something like this:
>>
>> CFLAGS="-O2 -march=native -mtune=native -pipe"
>>     
>
> Just a tiny hijack :-)
>
> My new laptop will have a T7100 CPU. I'd like to know what CFLAGS to use, 
> but even before that should I use an AMD64 or IA64 installation medium?
>
>   


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Re: [gentoo-user] CFLAGS

[Peter Humphrey]

On Thursday 17 January 2008 11:42:37 Tomas Papan wrote:

> in case that you want use 64bit system chose amd64 and -march=nocona

OK, thanks. What then is IA64 for?

-- 
Rgds
Peter
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Re: [gentoo-user] CFLAGS

[Kenneth Prugh]

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On Thu, 17 Jan 2008 12:38:47 +0000
Peter Humphrey <peter@humphrey.ukfsn.org> wrote:

> On Thursday 17 January 2008 11:42:37 Tomas Papan wrote:
> 
> > in case that you want use 64bit system chose amd64 and -march=nocona
> 
> OK, thanks. What then is IA64 for?
> 

Intel Itanium processors. (Your T7100 is a Core2)

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Re: [gentoo-user] CFLAGS

[Ricardo Saffi Marques]

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http://gentoo-wiki.com/Safe_Cflags

> Intel Core 2 Duo/Quad / Xeon 51xx/53xx
>
> vendor_id  : GenuineIntel
> cpu family  : 6
> model  : 15
> model name  : Intel(R) Core(TM)2 CPU XXXX @ XXXGHz
>
> *32 bit profile (x86)*
>
> CHOST="i686-pc-linux-gnu"
> CFLAGS="-march=prescott -O2 -pipe -fomit-frame-pointer"
> CXXFLAGS="${CFLAGS}"
>
> *64 bit profile (amd64)*
>
> CHOST="x86_64-pc-linux-gnu"
> CFLAGS="-march=nocona -O2 -pipe"
> CXXFLAGS="${CFLAGS}"
>
> *Note:*
>
>    - GCC 4.3 has -march=core2[1]<http://www.gnu.org/software/gcc/gcc-4.3/changes.html>,
>    but Gentoo has nothing above 4.2 in portage.
>
>

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Re: [gentoo-user] CFLAGS

[Peter Humphrey]

On Thursday 17 January 2008 15:36:51 Kenneth Prugh wrote:
> On Thu, 17 Jan 2008 12:38:47 +0000
> Peter Humphrey <peter@humphrey.ukfsn.org> wrote:
> > OK, thanks. What then is IA64 for?
>
> Intel Itanium processors. (Your T7100 is a Core2)

Of course. Thanks again; also to Etaoin.

-- 
Rgds
Peter
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Re: [gentoo-user] CFLAGS

[Alan McKinnon]

On Thursday 17 January 2008, Peter Humphrey wrote:
> On Thursday 17 January 2008 11:42:37 Tomas Papan wrote:
> > in case that you want use 64bit system chose amd64 and
> > -march=nocona
>
> OK, thanks. What then is IA64 for?


Itanium2.

You don't want to go there. Trust me.

It's a bastard evolution of one of Intel's worst ideas ever - Itanium, 
which was their first 64 bit effort. Only HP ever used it and it was a 
disaster in the market. Windows and Linux have never run on it. AMD did 
it right with amd64 which Intel copied as emt64. Meanwhile Itanium2 
came along, called IA64 in Linux terms. The only place you will ever 
see this architecture is in a data centre, and the machine will be at 
least 8 years old.

alan



-- 
Alan McKinnon
alan dot mckinnon at gmail dot com
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Re: [gentoo-user] CFLAGS

[Bo Ørsted Andresen]

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On Thursday 17 January 2008 17:10:11 Alan McKinnon wrote:
> Itanium2.
>
> You don't want to go there. Trust me.
>
> It's a bastard evolution of one of Intel's worst ideas ever

I thought that would be Pentium 4 EE. :P

-- 
Bo Andresen

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Re: [gentoo-user] CFLAGS

[Etaoin Shrdlu]

On Thursday 17 January 2008, Peter Humphrey wrote:

> Just a tiny hijack :-)
>
> My new laptop will have a T7100 CPU. I'd like to know what CFLAGS to
> use, but even before that should I use an AMD64 or IA64 installation
> medium?

Maybe this wiki page could help:

http://gentoo-wiki.com/Safe_Cflags
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[gentoo-user] CFLAGS

[Coert Waagmeester]

Hello all,

Possible noob question.

I have installed a 64 bit gentoo on my intel Pentium D machine.
Now I am reading through /usr/share/portage/config/make.conf.example

My CFLAGS on that machine is the default currently: CFLAGS="-O2 -pipe"
But according to 
http://www.gentoo.org/doc/en/gentoo-amd64-faq.xml#cflags I can make it:
-O2 -march=core2 -pipe

Is this entirely necessary? Will it cause a big improvement?

If I do change, how do I recompile everything? (like --newuse for USE 
changes?)

Thank you,
Coert Waagmeester

Re: [gentoo-user] CFLAGS

[Sebastian Beßler]

Am 02.11.2010 09:43, schrieb Coert Waagmeester:
> Hello all,

Hello!

> Possible noob question.

We all was noobs once, maybe I am still ;-)

> If I do change, how do I recompile everything? (like --newuse for USE
> changes?)

To recompile all use emerge -e world
The switch -e lets portage think that nothing is installed so it has to 
reinstall everything and his dependencies.

read man emerge for more informations.

Greetings

Sebastian

Re: [gentoo-user] CFLAGS

[Alan McKinnon]

Apparently, though unproven, at 10:43 on Tuesday 02 November 2010, Coert 
Waagmeester did opine thusly:

> Hello all,
> 
> Possible noob question.
> 
> I have installed a 64 bit gentoo on my intel Pentium D machine.
> Now I am reading through /usr/share/portage/config/make.conf.example
> 
> My CFLAGS on that machine is the default currently: CFLAGS="-O2 -pipe"
> But according to
> http://www.gentoo.org/doc/en/gentoo-amd64-faq.xml#cflags I can make it:
> -O2 -march=core2 -pipe

With a recent gcc (4.something) you should use

-O2 -march=native -pipe

Saves you having to figure out what the arch is.
 
> Is this entirely necessary? Will it cause a big improvement?

It will improve things by making all code optimized for your CPU if most of 
your binaries are still from the stage tarball and unoptimized for you.
You will be able to measure the difference with very fancy software.
You will not notice the difference. If you think you do, you are imagining it.
 
> If I do change, how do I recompile everything? (like --newuse for USE
> changes?)

emerge -e world

-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] CFLAGS

[Yohan Pereira]

On Tuesday 02 November 2010 2:13:41 pm Coert Waagmeester wrote:
> I have installed a 64 bit gentoo on my intel Pentium D machine.

also as far as i know, core2 is for core 2 duo quad etc cpus ... 
not for pentium D.

> -O2 -march=core2 -pipe

use native as Alan suggested.
or refer to 

http://www.gentoo-wiki.info/Safe_Cflags

-- 
- Yohan Pereira.

Re: [gentoo-user] CFLAGS

[Chris Reffett]

I feel like the Pentium D is "march=prescott" though, again, native
should work fine as well.
Chris Reffett
On 11/02/2010 06:40 AM, Yohan Pereira wrote:
> On Tuesday 02 November 2010 2:13:41 pm Coert Waagmeester wrote:
>> I have installed a 64 bit gentoo on my intel Pentium D machine.
> also as far as i know, core2 is for core 2 duo quad etc cpus ... 
> not for pentium D.
>
>> -O2 -march=core2 -pipe
> use native as Alan suggested.
> or refer to 
>
> http://www.gentoo-wiki.info/Safe_Cflags
>