Re: [gentoo-user] revdep-rebuild (gawk) issues

[Rafa Griman <rafagriman@gmail.com>]

On Tue, May 29, 2012 at 11:09 PM, Alan McKinnon <alan.mckinnon@gmail.com> wrote:
> On Tue, 29 May 2012 22:56:07 +0200
> Rafa Griman <rafagriman@gmail.com> wrote:
>
>> Hi Vaeth :)
>>
>> On Tue, May 29, 2012 at 7:02 PM, Vaeth
>> <vaeth@mathematik.uni-wuerzburg.de> wrote:
>> > On Tue, 29 May 2012, Rafa Griman wrote:
>> >>
>> >> gawk: cmd. line:3: error: Unmatched [ or [^: /[^[:space:]]/
>> >
>> >
>> > Your gawk is broken. This happens if you emerged gawk with
>> > current gcc and aggressive FLAGS like -DNDEBUG or -flto.
>> > Not sure whether it is a bug of gawk or gcc.
>>
>>
>> So it seems to be the CFLAGS :( As I said in my previous e-mail, I was
>> "experimenting" a bit with them ... I'll be more conservative ;)
>
> Well, on the one hand the flags don;t seem to be too bad overall, but
> on the other hand there's the golden rule of Gentoo:
>
> Don't stuff around with CFLAGS
>
> Why not? Well, there's the ricer phenomenon where changed CFLAGS
> worsen performance and stability but the user's own bias convinces
> him/her that it's actually vastly improved.


I know that rule and tried not to be too agressive but seems I was O:)
Since it's not my min machine, I was going to experiment (nothing
"scientific", just curiosity) trying different options on different
partitions and see how they work out.


> Some tweaks are perfectly OK, like the multimedia and cpu-specific
> stuff (sse, mmx and all their related cousins). These are normally safe
> and can give huge gains with video playback. Likewise for the GPU tweaks
> once those hit mainline usage.


That was mainly the reason: video playback and some other apps
(scientific). But nothing serious.


> One last tweak, if the code is built on the machine that will run it
> (the usual case, replace -march and -mtune with just "-march=native".
> It has exactly the same effect but is easier to read, is
> self-documenting and allows the compiler to attempt it's best (the
> compiler usually does know much better what to do than you do)

I totally agree with you: the compiler knos better ;)

TIA

   Rafa