On Wed, Jun 24, 2015 at 01:13:40PM +0200, Alan McKinnon wrote: > On 23/06/2015 15:05, behrouz khosravi wrote: > > Hello everyone. > > > > I really like to have control over my machine as much as possible. In > > this way I will learn a lot, so I am trying to remove all the default > > use flags and control them manually. > > > Here's some good advice: > > Don't do that. See below. >
Nonsense - do that. If your goal is to learn how stuff works and you're already reasonably familiar with C/C++ so you can debug any strange errors that can happen, have fun. Just don't think you'll get any real work done ;). i.e. it might be good to do this in a virtual machine and still have a stable system for work. > > > I just don't know which "global" use flags are absolutely necessary to > > the system to make it snappier or secure. > > That's a bit of a nonsensical line of thought, as what you think you > want doesn't really exist. > > ... > > Put "-march=native" in CFLAGS > Yes. Also, properly setting CPU_FLAGS_X86 is another thing that can speed up software *if* said software supports any special instruction sets. Most "normal desktop software" like web browsers, email clients, terminals, editors, etc. probably will not get a whole lot of benefit either way, since most of this software is generally not CPU-bound and is instead network/disk bound. In the mornings I primarily use my desktop for reading email and browsing news with firefox (mostly on sites with minimal JavaScript), and I have yet to see my load averages climb higher than maybe 0.5. Any software that does anything requiring lots of math will get a boost from this type of stuff, though; graphics editing, most things in sci-* categories, audio/video transcoding, etc. Alec P.S. Just realized I don't have "-march=native" in my CFLAGS. Time to rice - could be getting 1% better performance. ;) P.P.S. Also, on 1% better performance: My professor for the compilers class I took used to (maybe still does) work at Google. Apparently Google sees a <1% increase in performance as *the best thing ever*, because it can save them a bunch of money in infrastructure and power. Apparently Google are the ultimate ricers.
