Help with CFLAGS, USE FLAGS, profile, and modules reconfigur

Message

shgadwa · Post by **shgadwa** » Sat Mar 14, 2009 9:34 pm

I think I was a little too fast in my gentoo install. I did not read enough on CFLAGS, I just typed in what sounded good to me. My last cflag was -O and my first was -O2, and It also used the -mtune instead of -march.

I have a Toshiba L300 Satalite Pro Laptop, x86 1.86Ghz dual core CPU.

I think I want to go with these CFLAGS:

-march=native -O2 -pipe -fomit-frame-pointer

So, I guess now because I had the -O as being the last one... it caused problems... at least, the system is not as optimized. So, I need to reconfigure my Kernel, Xorg, and all my software... I'm wondering if it might be better to do a new install. But, my install is only a week old.

Also, any pointers on if I have the right CFLAGS, and also tips on USE flags and anything like that would be appreciated.

Also, -mtune=486 was specified by default in my system when I installed it. And I have a =486 CHOST as well. But its a dual core CPU (though not the best one, its a fairly fast, decent one)... So, I was tempted to change the CHOST to =i686.

One more quick question... the x86 Handbook mentioned changing the profile... and also something about 'adding modules.' I just skipped over this bit because I could not find any other profiles available for my system (ANYWHERE)... and did not see anything that talked about the modules. I did add the one the handbook said I could add though.

Thanks.

~Shawn[/quote]

Post by **NeddySeagoon** » Sat Mar 14, 2009 9:52 pm

belikeyeshua,

-march=native -O2 -pipe -fomit-frame-pointer is ok if your gcc supports -march=native.

As you have a i486 CHOST, you installed using the wrong stage3 tarball.
There is an x86 one for CPUs older then Pentium 2 and/or Pentium Pro and the i686 one for later CPUs.

The CHOST is not so important, it means your compiler will be a little slower than otherwise, as its built for a i486.
The content of make.conf is not used when you make a kernel. You tell the kernel what you want when you use make menuconfig.

If you want to change the CHOST, you can if you are careful. Follow the CHOST guide

In your place, I would change the CHOST then update the system weekly. Its usable but sub optimal. Optimisation will come as packages are updated. If you want to rebuld everything with the new compiler, you can ....

Code: Select all

emerge -e world

shgadwa · Post by **shgadwa** » Sat Mar 14, 2009 10:15 pm

NeddySeagoon wrote:belikeyeshua,

-march=native -O2 -pipe -fomit-frame-pointer is ok if your gcc supports -march=native.

As you have a i486 CHOST, you installed using the wrong stage3 tarball.
There is an x86 one for CPUs older then Pentium 2 and/or Pentium Pro and the i686 one for later CPUs.

The CHOST is not so important, it means your compiler will be a little slower than otherwise, as its built for a i486.
The content of make.conf is not used when you make a kernel. You tell the kernel what you want when you use make menuconfig.

If you want to change the CHOST, you can if you are careful. Follow the CHOST guide

In your place, I would change the CHOST then update the system weekly. Its usable but sub optimal. Optimisation will come as packages are updated. If you want to rebuld everything with the new compiler, you can ....
Code: Select all
emerge -e world

Does the 'right stage 3' have anything to do with where you download it from?? Here in Iceland, the Icelandic or German mirrors are about the fastest (about 1MB per second at most)... and I also have two options... the i686 stage 3 or the x86 stage 3... are they the same???

shgadwa · Post by **shgadwa** » Sat Mar 14, 2009 10:45 pm

Lastly, I am looking into USE flags... if I have a lot of USE flags, does that make my system slower??? (Of course, I would only use the USE flags that I would actually USE. I'm wondering if ther eis a limit or recommendation as to how many use flags to use.

Post by **NeddySeagoon** » Sat Mar 14, 2009 11:39 pm

belikeyeshua,

The i686 stage 3 and the x86 stage 3 are not the same. Here x86 means i486 and i585 class CPUs (i396 is no longer supported)
I686 means Pentium Pro, Pentium2 and later CPUs.
The differences are in the way the binaries are compiled and the CHOST. x86 uses i486 and i686 uses the i686 CHOST.

Use as many USE flags as you require, there is no limit. Get a USE Flag Editor, such as ufed or profuse to help you manage them.
USE flags select optional parts of packages, so if you set flags you don't need, your binaries will be bigger than they need to be and will take longer to load, however the unused code will be unused, so the run time performance will be the same.

d2_racing · Post by **d2_racing** » Sun Mar 15, 2009 2:52 am

Hi, can you post your actual emerge --info plz ?