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borkes
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Joined: 15 Jul 2007
Posts: 5

PostPosted: Fri May 30, 2008 7:30 am    Post subject: gentoo optimization Reply with quote

Hi, gurus!

I am interested in how optimization of source code compiling under certain architecture works. What is going on the level of compiler?
Are there real benefits of doing this? What is the achieved gain in performance?
Can you pls provide me with some benchmarks/articles about subj..

And another question is abt -Ox flags in make.conf. Are they worth using if X is higher than 2? Any examples would be appreciated! :)
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n00b
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Joined: 24 Dec 2007
Posts: 65
Location: Croatia

PostPosted: Fri May 30, 2008 7:56 am    Post subject: Reply with quote

I don't know the answers to all questions, but I can tell you the following (somebody correct me if I'm wrong):

The performance gain from compiling is, AFAIK, only 3-5%. You get also get some benefit from USE flags which allow you to install only what you really need (again, this affects disk space rather than performance).

The highest level is -O3. Any higher number is interpreted as 3.
For details refer to
$ man gcc
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gentoo-dev
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Joined: 24 Jan 2006
Posts: 172

PostPosted: Fri May 30, 2008 10:59 am    Post subject: Reply with quote

http://www.gentoo.org/doc/en/gcc-optimization.xml
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muhsinzubeir
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Joined: 29 Sep 2007
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PostPosted: Fri May 30, 2008 11:45 am    Post subject: Reply with quote

next time search first b4 you post....i mean in a good way :wink:
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nixnut
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Joined: 09 Apr 2004
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PostPosted: Fri May 30, 2008 5:37 pm    Post subject: Reply with quote

Moved from Kernel & Hardware to Duplicate Threads.

See here, here, here, definitely here, here, and here.
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