ld flag that gives ~40% startup time boost

[John Richard Moser]

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James Laver wrote:
> Yes, yet when I saw that, I was thinking `that's an odd warning
> level`. A check of the docs for gcc later and I still can't find any
> note of it. Would you like to explain a touch more about how it
> affects things?
> 

- -Wl tells gcc to tell the linker to do something; so -Wl,-O1 tells gcc
to tell ld to use -O1.

gcc infile.c -o outfile

becomes (effectively) -->
gcc infile.c | ld -o outfile

Or some such.

gcc -Wl,-O1,--relax,-znow infile.c -o outfile

becomes (effectively) -->
gcc infile.c | ld -O1 --relax -znow -o outfile

And so on.

In short, rtfm for ld, not gcc.


> Thanks
> 
> On 22/06/06, John Richard Moser <nigelenki at comcast.net> wrote:
> 
> 
> James Laver wrote:
>> With gentoo it's largely in the users' hands. They can build the base
>> tarball with whatever switches they like, but by the time it comes
>> round to updates of the system, a lot of core things will be updated
>> and compiled with your global make.conf options.
> 
>> On a sidenote, I'm rather fond of -O3 where it works (sqlite, for
>> example), but i typically go -O2 for most of my compiles.
> 
> 
> -O3 and -O2 do nothing with -Wl,-O; it's a binary switch.
> 
>> Obviously start up speed is a big factor, it's what everyone whines
>> about, and I mean everyone.
> 
> I'm currently looking into other things like --relax (which... does
> what?  The man page is very vague) and anything else I can come across
> that's harmless.  It's hard to know exactly what the environment on the
> build server looks like though, since ubuntu doesn't seem to have this
> documented anywhere I can easily locate... (one of the devs told me he
> "thinks" -Wl,-O1 is in the ENV on the build server)
> 
> 
>> On 22/06/06, Scott James Remnant <scott at ubuntu.com> wrote:
>>> On Thu, 2006-06-22 at 15:51 -0400, John Richard Moser wrote:
> 
>>> > Does Ubuntu build everything with -Wl,-O1?  This was something that
>>> > Gentoo did as an optimization;
>>> >
>>> Yes, we do; Gentoo started doing it because we did.
> 
>>> Scott
>>> --
>>> Scott James Remnant
>>> scott at ubuntu.com
> 
> 
>>> 

>>
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