[gcc 3.4] AMD's Recommended CFLAGS

[nxsty]

sigmalll: True, but the problem is that there is no magic CFLAGS that will make your system faster. So when choosing global CFLAGS they should always be "-O2 -march= -pipe" and perhaps also omitfp if you're on x86. It doesn't matter if -O3 is shown to be faster in some benchmarks, it shouldn't be used globaly anyway because 99% of the packages wont benefit from the higher optimizations and will in fact often run slower because of the extra bloat it causes.

[sigmalll]

[cybrjackle]

I use hardcore ricing flags

[LoSeR_5150]

I am fairly new to gentoo, but within my 10mo. i have wasted tons of time playing with cflags, well i guess not wasted because i think i learned from the experience. My cflags used to look like this:

[MorLipf]

My current Cflags are:

[nxsty]

[robak]

i just tried a few CFLAGS to optimize POVray but the best result i could get is 28min 34 sec on this hardware:

AMD Athlon64 3000+ 1,8Ghz Venice-core
2*512 MB RAM in Dual-ChannelMode

can someone tell me how to optimmize the system to get better results.
i was compiling world for about 3 days now (i have "only" 135 packages to compile, so i could test a lot of FLAGS combinations) and i a little bit tied

[mbar]

or you could just overclock your CPU by mere 200 MHz and make it really fly faster, no ricer CFLAGS would do it instead

I settled on "-Os -march=k8 -pipe -fomit-frame-pointer -falign-functions=5"

[alexlm78]

Interesting, i should try it.!!!!!!!
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[HacTek]

forgive my naivety, but is there a way to specify cflags on a package-by-package basis?
something similar to the way use flags can with the package.use file.

if not then why not?

seems like from this debate that a simple solution would be to set some safe and sensible cflags for the system.
perhaps

[barry]

It's important to remember that a lot of these high performance optimisation flags are designed for developers to compile and test their software to get the best perfomance out of them. They were never intended for use to compile an entire production system blindly with.

As others have said, most of the packages that will receive massive perfomance gains with flags like -funroll-loops and -ffast-math already have these included in the ebuild so you don't need to enable them yourself.

"-march=k8 -O2 -pipe" should produce excellent optimised and rock solid code for everybody, and the builds like mplayer, lame and so on will already have safe higher performing flags applied.

"-march=k8 -O2 -pipe -frename-registers -fweb" is the same as doing -O3 but misses off a single flag that bloats code and quite often causes a slow down, so these flags will generally improve performance over a plain -O2 without breaking anything.

[SoTired]

[HacTek]

it looks like a pretty good script to me.
not that i have any experience with bash scripting but i gotta learn sometime.

is there any active development happening with this approach?
looks like a good candidate for moving towards an offically supported feature.
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[pacho2]

[loftwyr]

If you didn't have SSE3, it would have given an error instead of a result.

Your processor has SSE3
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[pacho2]

Thanks

[clytle374]

I have decided that some here work for MS: either trying to make linux as slow as windows, or as unstable as windows.

Now i will have to break it to find out who.