Extreme CFLAGS problems...

resolute · n00b Joined: 23 Jan 2005 Posts: 29 Location: Texas, USA

I don't think the Gentoo developers care at all if anyone breaks their system with insane CFLAGS.
I do think the Gentoo developers care when they have to wade through useless bug reports about the aftermath though.
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Hell · n00b Joined: 05 Dec 2004 Posts: 10

How about simply just implementing a standard to use? Put it in the handbook and make it clear (in bold letters) that using these flags are safe to use and anyone breaking away from it is more than likely not guaranteed any support (unless approved by the Gentoo devs). The current handbook doesn't really make anything clear about the make.conf and cfflags, especially for migrating users who are reading about these great CFFLAGS for improving performance and such on the forums. Then at aleast anyone is welcome to use whatever flags they want and you can use a ritual "We don't support your current settings, goodbye" for replies for help (unless someone is willing).

There are a couple websites offering "safe" flags to use, but I'm not so sure anymore if they are considered "safe" and still be able to gain support. And I really don't mind the filtering of flags though, I'm sure the people that want to circumvent these filterings will and should KNOW how to do it anyways.

vdboor · Posted: Mon Jan 24, 2005 12:42 pm Post subject:

I agree with the opinions of 'ciaranm' and 'Hell'.

Limiting choice (or producing a big warning sign) could scare some people off. But it could make the Gentoo community a lot healthier.

The piont 'Hell' is trying to make is valid, the Gentoo handbook doesn't educate users much about CFLAGS, nor does the Gentoo website. In fact, the Gentoo website even advertises with "speed" as one of the major benefits of Gentoo! Talking about attracting the wrong people...

My CFLAGS are sane, but I also make the mistake of trying -O3, -Os and -ffast-math (and a few others recommeded at freehackers.org). And I'm just a 'average' user who just doesn't want to surf the net looking for the right packages. It's very simple: if you hear a story enough times, you'll start to believe there could be some truth in it... [and follow the croud]

Talking about advantages (except for the speed-hoax), I think it's the openess, flexibility, initscripts and package availability. I still have to experience that speed difference coming from Slackware. I've read a response at slashdot from a Gentoo user compiling it's entire system with '-O0 -g' to produce usefull debug reports. Try that on any other disto..

Such options should be advertised, not speed!
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ciaranm · Posted: Mon Jan 24, 2005 1:19 pm Post subject:

truekaiser · l33t Joined: 05 Mar 2004 Posts: 801

i am looking thorugh the bugzilla docs and i am wondering why you can't just use it's search features to show only the bugs with sane cflags.

rhill · Posted: Tue Jan 25, 2005 3:57 am Post subject:

truekaiser · l33t Joined: 05 Mar 2004 Posts: 801

hmm interesting. they can't ignore a few nuts but are perfectly able to ignore the same amount of people in the fourms...

silverpig · Posted: Thu Jan 27, 2005 6:57 pm Post subject:

-march=pentium-m -02 -fomit-frame-pointer -pipe

Everything works beautifully

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ciaranm · Posted: Thu Jan 27, 2005 7:02 pm Post subject:

lightvhawk0 · Guru Joined: 07 Nov 2003 Posts: 388

rhill · Posted: Fri Feb 04, 2005 2:41 am Post subject:

man, i was an ass in this thread. :oops:

sorry ciaran, you caught me the week my grandpa passed away.
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legine · Guru Joined: 27 May 2004 Posts: 555 Location: Germany

Hmm, I believe I use the CFlags given in the Handbook. (Hmm, Okey I did not enter -pipe and forgot to set the CXXFLAG <-

put them in hopefully nothing changes

)
My gentoo is realy fast. faster then my Fedora installaton. And I am satisfied with the speed I got with this optimisations)
The problem is more Gentoo offeres Choices, the more choices the more people try. Most companies try to chanell the choice (you get what you need) to avoid these problems :/
Which of corse brings other problems up.
I like to have the choice. And I would appreciate if the handbook is linked with a documentation of Flags wich are not to use if you wnat a stable system (and maybe support/right to send in Bug reports). This informs you over the consequneces of the choice you have and everybody (newbees too) when get some general guidance. (which is done best of all Distros I know of)
Some people did say this already, I think, and I like this Idea. I want this attitude backed more up.

legine · Guru Joined: 27 May 2004 Posts: 555 Location: Germany

Hmm, I do not like Debian because I had bad starting expirence. Its nothing worth speaking of, but I was a real noob with real lack of knowledge (and this I had a lot). Since that time I do not like bunch Mailinglists withup to 600 Mails a day. (I of course got all Mailing list because you never now when you need one

)
And I do not like binaries. I never need that what I am looking for. Binaries have the disadvantages that they are no way that flexible like a swift compile.

Now there was a statement that people made theire Choices and try to defend them. I support this!
I believe that this hole a vs. b is natural good thing. (As long as this does not become violent, then you should train you lack of selfcontrol

)
IMHO it is good because you can test your choice, if it is right if it is the one you made correct. You lcompare youre choices to others and determine in a confrontation if this is the best to do.

(Thanks for this nice Debian forum! I bookmarked it. Maybe I give them another shot someday.)

BrightSide · Posted: Sat Feb 12, 2005 10:56 pm Post subject:

I guess the one thing we call all agree on is: GCC has sometimes been known to break things

Xaignar · Posted: Sat Feb 12, 2005 11:30 pm Post subject:

Lokheed · Posted: Sun Feb 13, 2005 1:26 am Post subject:

Bob P · Posted: Fri Feb 18, 2005 4:54 am Post subject:

Archangel1 · Veteran Joined: 21 Apr 2004 Posts: 1212 Location: Work

I like Hell's idea - a bit more information in the CFLAGS section in the manual wouldn't go amiss. A few more example -march settings maybe, and then say specifically that "-O2 -fomit-frame-pointer -pipe" (or whatever) is okay, and anything else may well lead to problems.
IIRC, the current one makes it sound very open to experimentation. Of course it is, but I think it might encourage a little more recklessness with it than is really a good idea.

However there has to be a happy median; Gentoo is about choice, and we don't want to try to stop users from optimising if they so choose - we just need to make it a bit more obvious that they're not going to get a lot of sympathy if they go beserk on CFLAGS.
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augury · l33t Joined: 22 May 2004 Posts: 722 Location: philadelphia

I don't think theres a fully defined set of good/bad flags. gcc is vague in the documentation when it comes to this. the optimizations are simply the algorithms it is programmed to preform. if you like it, take it.

I've used these flags on all packages including striped ebuild and i haven't broken anything (major)

augury · l33t Joined: 22 May 2004 Posts: 722 Location: philadelphia

i also use param's but i pre-defined them into gcc. im pretty sure -O3 is safe on everything since it also is coded to just use -O3 and ftracer unless i -fno each and every flag.

TheCoop · Posted: Mon Mar 14, 2005 8:23 am Post subject:

charlieg · Posted: Mon Mar 14, 2005 11:28 am Post subject:

Somebody who knows / cares / has-the-time should put up a more detailed page on www.gentoo-wiki.com going over some of the lesser known cflags. Then perhaps people can write down their experiences against each one (packages that don't build, etc).

I found that perl doesn't build with CFLAGS := " -fvisibility=hidden" and CXXFLAGS := " -fvsibility-inlines-hidden" (although I don't know which one specifically causes it to fail, the former probably).
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charlieg · Posted: Mon Mar 14, 2005 11:36 am Post subject:

Birtz · Posted: Mon Mar 14, 2005 1:21 pm Post subject:

spb · Posted: Mon Mar 14, 2005 5:02 pm Post subject: