arch KDE packages not compiled using -fpic ?

brazzmonkey · 2006-08-29 09:49:01

this week-end i gave prelink a shot. then i realized that actually most (if not all) kde apps could not be prelinked.
it looks like they're not compiled with -fpic option, and prelink cannot "link against non-pic libraries".
it's not that i absolutely want to prelink my whole system, it's just that i thought this -fpic option was a good thing so i'm surprised it's not used in arch kde packages.
any plans to enable -fpic for kde in the near future ?

Gullible Jones · 2006-08-29 15:38:53

I thought using -fpic slowed things down if they weren't prelinked?

test1000 · 2006-08-29 20:13:58

-fpic hmm.. never knew of that. To "prelink" a lot of KDE apps though you can launch kdeinit & at xorg startup (.xinitrc for example). Although i'm not 100% on this.

brazzmonkey · 2006-08-29 21:22:14

Gullible Jones wrote:

I thought using -fpic slowed things down if they weren't prelinked?

never heard about that. are you sure ?
@test1000 : i know you can skip kdeinit if kde is prelinked, by setting KDE_IS_PRELINKED to 1. i didn't know about this trick, though. maybe i'll give it a shot, but i suspect kdeinit should be launch once user is logged in.

chrismortimore · 2006-08-30 09:22:56

-fpic can reeaalllyy slow stuff down that isn't prelinked (I discovered that on my gentoo box), and it also breaks some things (can't remember the specifics). As far as I am aware, you shouldn't be using -fpic unless you really know what you are up to. And in my experience, even with KDE_IS_PRELINKED set, kdeinit still gets used, but I don't know if that was just me being stupid or not.

brazzmonkey · 2006-08-30 09:49:06

a few months ago, i had a gentoo box compiled with USE="pic" and didn't encounter any problems. but this use flag is not used by every ebuild.
i didn't know -fpic could slow things... and never noticed it.

chrismortimore · 2006-08-30 09:51:46

brazzmonkey wrote:

a few months ago, i had a gentoo box compiled with USE="pic" and didn't encounter any problems. but this use flag is not used by every ebuild.
i didn't know -fpic could slow things... and never noticed it.

I don't notice the slowdown on my Athlon64, but on my old (socket A) Sempron 2500+ and my even older (socket A) Duron 1.2GHz, you can really feel it. Probably because the Athlon64 has enough grunt to cover the slowdown though

brazzmonkey · 2006-08-30 10:04:19

mine is a duron 1.3 ghz. once prelink is installed on gentoo, every program that can be prelinked is prelinked. maybe this explains why i never encountered any slowdowns...

chrismortimore · 2006-08-30 10:20:53

brazzmonkey wrote:

mine is a duron 1.3 ghz. once prelink is installed on gentoo, every program that can be prelinked is prelinked. maybe this explains why i never encountered any slowdowns...

On my Duron, I found (for a reason I'm yet to uncover) that when the system was prelinked, the CPU kept overheating (majorly overheating). Yet, when I unprelinked it, temperatures returned to normal. So I unprelinked, and the system was a lot slower than before. I think I should submit that to Ripley's Believe It Or Not...

brazzmonkey · 2006-08-30 11:57:51

overheating !? damn ! that's weird.
personally i never checked the temps. i don't want to be scared by those numbers. they lead you to some kind of paranoia. proper cooling is all we need...

it's funny how gentoo and arch communities don't agree on prelink : many gentoo users think it's a speed enhancement (for launching program at least), whereas on these forums it is considered as deprecated and useless.

i don't know what to think, really. and i won't recompile the whole kde thing just to see whether prelink speeds things up a (very little) bit.

chrismortimore · 2006-08-30 16:12:10

Personally, I found LDFLAGS can do just as much as prelinking, and it's easier to maintain, it's a whole less command to type after an upgrade/install

Gullible Jones · 2006-08-30 17:57:19

LDFLAGS can also really screw you up if you aren't careful, as I discovered on Gentoo.

brazzmonkey · 2006-08-30 19:48:29

yes, but changing LDFLAGS means re-compiling. no ?

chrismortimore · 2006-08-30 19:52:02

brazzmonkey wrote:

yes, but changing LDFLAGS means re-compiling. no ?

Yup.

brazzmonkey · 2006-08-30 20:18:46

otoh, you may say that if i want my kde to be prelinked, i need to re-compile it too...
so i suppose the best is to leave things as they are

chrismortimore · 2006-08-30 21:07:55

brazzmonkey wrote:

otoh, you may say that if i want my kde to be prelinked, i need to re-compile it too...
so i suppose the best is to leave things as they are

Yeah

superstoned · 2006-09-04 10:03:00

prelinking kde and using KDE_IS_PRELINKED=1 is slower than using kdeinit so if compiling with -fpic is a slowdown, it's smart not to use it...

now i'd love to tell where i read this, but it's some time ago on a KDE blog. i've used to run gentoo, and try to optimize it - but arch is clearly faster here. i used prelink (and KDE_IS_PRELINKED=1) on gentoo - it sucks to read some time later it didn't help at all ;-)

anyway, i think the reason was kdeinit can spawn new processes faster than they can be started, even with prelink...

brazzmonkey · 2006-09-04 12:38:34

kde + prelink used to work fine on my gentoo.

superstoned · 2006-09-04 13:25:04

i didn't say it didn't work, just that it didn't have any advantages in speed over kdeinit, and in fact the latter is faster.

brazzmonkey · 2006-09-04 14:54:32

well i meant kde did start faster. not for everybody, though, according to many discussions on gentoo forums.

superstoned · 2006-09-04 17:27:59

brazzmonkey wrote:

well i meant kde did start faster. not for everybody, though, according to many discussions on gentoo forums.

well, it might very well be that KDE itself startsup faster with prelink, but the subsequent starting of apps is faster with kdeinit... it does sound reasonable, imho.

brazzmonkey · 2006-09-04 20:40:41

sure thing. but obviously it depended on the app...

Arch Linux

#1 2006-08-29 09:49:01

arch KDE packages not compiled using -fpic ?

#2 2006-08-29 15:38:53

Re: arch KDE packages not compiled using -fpic ?

#3 2006-08-29 20:13:58

Re: arch KDE packages not compiled using -fpic ?

#4 2006-08-29 21:22:14

Re: arch KDE packages not compiled using -fpic ?

#5 2006-08-30 09:22:56

Re: arch KDE packages not compiled using -fpic ?

#6 2006-08-30 09:49:06

Re: arch KDE packages not compiled using -fpic ?

#7 2006-08-30 09:51:46

Re: arch KDE packages not compiled using -fpic ?

#8 2006-08-30 10:04:19

Re: arch KDE packages not compiled using -fpic ?

#9 2006-08-30 10:20:53

Re: arch KDE packages not compiled using -fpic ?

#10 2006-08-30 11:57:51

Re: arch KDE packages not compiled using -fpic ?

#11 2006-08-30 16:12:10

Re: arch KDE packages not compiled using -fpic ?

#12 2006-08-30 17:57:19

Re: arch KDE packages not compiled using -fpic ?

#13 2006-08-30 19:48:29

Re: arch KDE packages not compiled using -fpic ?

#14 2006-08-30 19:52:02

Re: arch KDE packages not compiled using -fpic ?

#15 2006-08-30 20:18:46

Re: arch KDE packages not compiled using -fpic ?

#16 2006-08-30 21:07:55

Re: arch KDE packages not compiled using -fpic ?

#17 2006-09-04 10:03:00

Re: arch KDE packages not compiled using -fpic ?

#18 2006-09-04 12:38:34

Re: arch KDE packages not compiled using -fpic ?

#19 2006-09-04 13:25:04

Re: arch KDE packages not compiled using -fpic ?

#20 2006-09-04 14:54:32

Re: arch KDE packages not compiled using -fpic ?

#21 2006-09-04 17:27:59

Re: arch KDE packages not compiled using -fpic ?

#22 2006-09-04 20:40:41

Re: arch KDE packages not compiled using -fpic ?

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