Re: Optimization levels when compiling PostgreSQL... - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Optimization levels when compiling PostgreSQL...
Date
Msg-id 200209100304.g8A34wK09763@candle.pha.pa.us
Whole thread Raw
In response to Re: Optimization levels when compiling PostgreSQL...  (Sean Chittenden <sean@chittenden.org>)
Responses Re: Optimization levels when compiling PostgreSQL...  (Sean Chittenden <sean@chittenden.org>)
List pgsql-hackers
Sean Chittenden wrote:
> > > > The size difference between -O and -O3 is only 200K or so... does
> > > > anyone think that it'd be safe to head to -O6 on a wide scale?
> > > 
> > > Dunno.  I'm not aware of any bits of the code that are unportable enough
> > > to break with max optimization of any correct compiler.  But you might
> > > find such a bug.  Or a bug in your compiler.  Are you feeling lucky
> > > today?
> > > 
> > > My feeling is that gcc -O2 is quite well tested with the PG code.
> > > I don't have any equivalent confidence in -O6.  Give it a shot for
> > > beta-testing, for sure, but I'm iffy about calling that a
> > > production-grade database release...
> > 
> > And of course the big question is whether you will see any performance
> > improvement with -O6 vs. -O2.  My guess is no.
> 
> Agreed, however some of the loop-unrolling might prove to have some
> optimization, but we'll see.  I'd like to think that there's some
> actual value in -O6 beyond the geek appeal of being able to say it's
> been compiled with all the optimizations possible.  ::shrug::

And you think the answer is ...  I think we all know what the answer is.
:-)

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 


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