Re: Release Building and /etc/make.conf

On Friday 23 January 2004 07:34 am, Bruce Evans wrote:
> On Wed, 21 Jan 2004, John Baldwin wrote:
> > On Tuesday 20 January 2004 11:58 pm, Bruce Evans wrote:
> > > i386 (or equivalently, no special tuning) is the best default, at least
> > > in non-FPU-intensive applications.  In my integer crunching
> > > application/ benchmark (searching a game tree), it even gives better
> > > results than -mcpu=pentiumpro on a pentiumpro class machine (a 366MHz
> > > Celeron). -mcpu=athlon-xp gives even better results.
> > >
> > > All with -O3 -fomit-frame-pointer
> > > -mcpu-athlon-xp        48.42 real        47.31 user         0.41 sys
> > >                        51.22 real        50.10 user         0.30 sys
> > > -mcpu=i386             51.98 real        50.18 user         0.34 sys
> > > -mcpu=pentiumpro       56.38 real        55.26 user         0.34 sys
> > > -mcpu=pentium2         56.24 real        55.25 user         0.36 sys
> > > -mcpu=pentium3         56.59 real        55.25 user         0.40 sys
> > > -mcpu=pentium4         58.52 real        56.96 user         0.36 sys
> > > -mcpu=i486             79.17 real        77.69 user         0.32 sys
> > > -mcpu=i586             74.80 real        73.07 user         0.48 sys
> > >
> > > This is just one benchmark, chosen for its potential optimizability.
> > > I only did non-exhaustive benchmarks for the makeworld benchmark.  I
> > > removed the -mpentiumpro change when I saw the kernel size bloat that
> > > it gave.
> >
> > Does -mcpu=althon-xp perform worse than the default in other benchmarks
> > that you've run?
>
> I haven't run enough to be sure.  It's hard to test all the combinations
> for long enough.  Some quick tests with the cc1 application/benchmark:
>
> cc1 compiled with -O3 -fomit-frame-pointer, and:
>     -mcpu=i386 (code o3)
>     -mcpu=i486 (o4)
>     -mcpu=pentiumpro (op)
>     -mcpu=athlon-xp (oa)
> Times for the "all" part of "make obj; make depend; make all" starting
> with an empty object tree and source tree = src/bin on the Celeron and
> src/usr.sbin on the Athlon (it doesn't complete because it wants to
> link to never-installed unbuilt libraries, but it gets a fair way).
> Smallest real time for 2 runs:
>
> On a Celeron 400 with source tree src/bin:
> o3:      121.94 real        97.14 user        19.94 sys
> o4:      130.83 real       106.59 user        19.07 sys
> oa:      122.69 real        97.58 user        19.39 sys
> op:      124.01 real        99.54 user        19.56 sys
> All non-null -mcpu settings are pessimizations, with -mcpu=i486
> significantly bad and -mcpu=pentiumpro probably significantly bad.
> Optimizing the pentiumpro class machine as an athlon-xp works
> better (less worse here) than optimizing it as a pentiumpro in this
> benchmark too, but the differences are smaller
>
> On an Athlon-XP1600 overclocked with source tree src/usr.sbin:
> o3:       67.62 real        57.46 user         9.53 sys
> o4:       69.09 real        57.65 user        10.20 sys
> oa:       67.53 real        56.78 user         9.62 sys
> op:       68.14 real        57.47 user         9.70 sys
> Most of the differences are too small to be significant.  Optimizing
> the athlon-xp as an athlon-xp at least doesn't pessimize it.
>
> My integer-crunching benchmark shows similarly small differences on
> freefall, but that may be just because freefall's gcc is so old.

Hmm, well, I'm ok with dropping the mcpu=ppro from bsd.cpu.mk for the default 
case then.

-- 
John Baldwin <jhb_at_FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org