Just setup a linode today and I'm currently using Gentoo (the only distro I know). I have a couple other Gentoo servers at home and work and the CFLAGS I've been using are

CFLAGS="-O3 -march=<whatever.arch.it.is> -fomit-frame-pointer -pipe"

Are there any CFLAGS I should use or avoid on my linode?
What about USE flags?

This is what I've added to my make.conf file:

USE="apache2 cjk fam gd imagemagick imap maildir mysql sasl unicode -oss -alsa -apm -arts -avi -cups -encode -foomaticdb -gpm -gtk -gtk2 -imlib -kde -gnome -libg++ -mad -mikmod -motif -mpeg -oggvorbis -opengl -qt -quicktime -sdl -svga -truetype -X -xmms -xv"

I haven't changed the CFLAGS, and I'm not sure what I'd change them for anyway.



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_________________
Programs that crash have been proven to be less useful than those that don't.
• Apple TechNote 117 •

I'm no programmer so I don't really know what they all mean, but I think the CFLAGS have to do with compiler optimizations. Check out this thread from the Gentoo Forums. I was hoping someone might be able to recommend some CFLAGS that would be beneficial in a UML environment... cuz this stuff is all Greek to me.

Oh.. and from what I understand.. adding atleast "-fomit-frame-pointer" boosts performance or memory usage or something... and it's a pretty "safe" CFLAG to use, so why not? Anyone else have recommendations or advice?

At home I use:

CFLAGS="-O2 -march=pentium3 -fprefetch-loop-arrays -pipe"

Although you most likely want -march=athlon-xp instead of -march=pentium3 on your linode.

-O3 often isn't faster than -O2. Try it and see.


Personally I would rather use debian on a linode. Gentoo may be a great system but it use a fair old amount of space for the portage tree.

-fomit-frame-pointer disables the use of a CPU register as a frame pointer. Upside: having another register available makes software run faster (less frequent access to memory). Downside: stack trace debugging is disabled - but you probably don't care unless you are developing or seriously testing software on your Linode.


Linodes are dual Xeon boxes so -march=pentium3 is presumably the way to go.

Tinkering with CFLAGS is a surprisingly easy way of building software that bombs in obscure circumstances. Unless you are doing something very unusual with your Linode, you will be I/O bound, not processor bound and I would stick with the defaults.

I would assume caker set some good defaults for the CFLAGS, so I have never looked into changing them...

The USE flags on the other hand could use some tweaking in the default setup. They are very desktop-centric, which is probably not what most people want/need from a Linode...

_________________
Programs that crash have been proven to be less useful than those that don't.

• Apple TechNote 117 •

Good point... I don't consider my CFLAGS to be overly aggressive so I think I'm fine for now... I don't plan to tinker with them anymore.


Actually, in my Gentoo setup I didn't notice any CFLAGS at all.

CFLAGS are set in /etc/make.globals.

emerge info will tell you what your defaults are - my Linode gives CFLAGS="-O2 -mcpu=i686 -pipe" which is unchanged since distro install and pretty conservative.