From: Daniel van Ham Colchete <daniel.colchete@gmail.com>
To: Florian Weimer <fweimer@bfk.de>
Cc: Cosimo Streppone <cosimo@streppone.it>
Cc: Postgresql Performance list <pgsql-performance@postgresql.org>
Subject: Re: New to PostgreSQL, performance considerations
Date: Tue, 12 Dec 2006 13:57:20 -0200
Message-ID: <8a0c7af10612120757t3e2add5ckb512af8f794a2235@mail.gmail.com> (raw)
In-Reply-To: <82psapuos8.fsf@mid.bfk.de>
References: <C1A31C39.15548%llonergan@greenplum.com>
<457EA39E.1020207@streppone.it>
<82psapuos8.fsf@mid.bfk.de>
On 12/12/06, Florian Weimer <fweimer@bfk.de> wrote:
> * Cosimo Streppone:
>
> > "-O0" ~ 957 tps
> > "-O1 -mcpu=pentium4 -mtune=pentium4" ~ 1186 tps
> > "-O2 -mcpu=pentium4 -mtune=pentium4" ~ 1229 tps
> > "-O3 -mcpu=pentium4 -mtune=pentium4" ~ 1257 tps
> > "-O6 -mcpu=pentium4 -mtune=pentium4" ~ 1254 tps
>
> -mcpu and -mtune are synonymous. You really should -march here (but
> the result is non-generic code). Keep in mind that GCC does not
> contain an instruction scheduler for the Pentium 4s. I also believe
> that the GCC switches are not fine-grained enough to cover the various
> Pentium 4 variants. For instance, some chips don't like the CMOV
> instruction at all, but others can process it with decent speed.
You can use -march=pentium4, -march=prescott and -march=nocona to the
different Pentium4 processors. But you have to use -march (and not
-mcpu or -mtune) because without it you are still using only i386
instructions.
Daniel
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To: pgsql-performance@postgresql.org
Cc: daniel.colchete@gmail.com, fweimer@bfk.de, cosimo@streppone.it
Subject: Re: New to PostgreSQL, performance considerations
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