Noob question abouts ABS, makepkg and optimizations

Serge2702 · 2015-06-02 16:49:05

After using Gentoo for a week I wanted to compile everything that moves, and I wanted to do the same in Arch using the ABS, but after reading the makepkg article on the wiki I learned that it's only worth it for resource heavy applications. So I started to compile the lisp interpreter sbcl, the lua interpreter (for awesome), octave, etc. But I have a doubt: assuming that code compiled with -march=native is indeed better than the default packages, what are the things that are necessary to compile for a real optimization? Only the top package? Also it's makedepens? It's dependencies? All of the above? None of the above? (I suppose that it's completely useless to repackage things that are interpreted instead of compiled, like things that depend on python)

Thanks for your time.

Alad · 2015-06-02 17:18:29

I'm going with "None of the above." You have to compare "performance benefits" against what's likely a logistical nightmare. Use options such as graysky's kernels (see linux-ck on the wiki) if you want.

Last edited by Alad (2015-06-02 17:28:18)

Head_on_a_Stick · 2015-06-02 20:09:03

I would propose that you will spend more time custom compiling applications than you will save from said customisations.

Serge2702 · 2015-06-03 05:53:45

Oh, ok. Well, I could swear that the temperature of my laptop is like ~3°C lower after installing a few custom packages, but maybe that's just the placebo effect. Also I don't spend a lot of time compiling because I leave the packages compiling in a spare computer in the night, and then I install them in the morning. But I agree, I think that I should stop because most likely in the end I wont even notice any difference.

On a side note, one month ago I installed the linux-ck kernels from graysky's repositories, but I didn't like it because for some reason the temperature of my laptop was almost 20°C above average, normally it's ~45°C at idle, but with that kernel it was near 65 °C.

Thank you for your replies.

Trilby · 2015-06-03 10:56:08

The march flag itself will have no detectable effect in most cases - the exceptions might be heavy number crunching, simulation, and/or audio/video editting software (just some guesses). But even with these, you might only *detect* a different if you design artificially complex tasks for those software tools and time them to ms accuracy.

But Gentoo's approach has many other benefits. The most notable one would be the USE flags. You can partially replicate this by building your own packages from source to eliminate unneeded dependencies and/or linking to libraries you don't want. I do this with mpv (just because the stock repo package now depends on a bunch of crap I don't want and should not be needed for a video player - why on earth does a video player need access to network printers!). I also used to build my own vim (based roughly on a PKGBUILD from JWR) but now vim-minimal from the repos is pretty close to my own build, so I just use that.

So in short, the compiler optimizations themselves will rarely (if ever) be worth the effort. But building your own versions of packages if you actually modify configure options can have noteworthy benefits ... sometimes.

Arch Linux

#1 2015-06-02 16:49:05

Noob question abouts ABS, makepkg and optimizations

#2 2015-06-02 17:18:29

Re: Noob question abouts ABS, makepkg and optimizations

#3 2015-06-02 20:09:03

Re: Noob question abouts ABS, makepkg and optimizations

#4 2015-06-03 05:53:45

Re: Noob question abouts ABS, makepkg and optimizations

#5 2015-06-03 10:56:08

Re: Noob question abouts ABS, makepkg and optimizations

Board footer