On Mon, Jan 30, 2023 at 10:47 AM Andres Freund wrote:
> For some reason my notes for using LTO include changing RANLIB to point to
> gcc/llvm-ranlib of the appropriate version. Won't even be used on HEAD, but
> before that it can make a difference.
>
I will try that.
> Depending on how you bui
Hi,
On 2023-01-30 10:24:02 -0700, João Paulo Labegalini de Carvalho wrote:
> > What compiler / version / flags / OS did you try?
> >
>
> I am running experiment on a machine with:
>
>- Intel(R) Xeon(R) Platinum 8268 CPU @ 2.90GHz
>- Ubuntu 18.04.6 LTS
>- LLVM/Clang 15.0.6 (build from
> What compiler / version / flags / OS did you try?
>
I am running experiment on a machine with:
- Intel(R) Xeon(R) Platinum 8268 CPU @ 2.90GHz
- Ubuntu 18.04.6 LTS
- LLVM/Clang 15.0.6 (build from source)
These are the flags I am using:
CFLAGS = -O3 -fuse-ld=lld -gline-tables-only -fpr
Hi,
On 2023-01-27 18:28:16 -0500, Tom Lane wrote:
> Andres Freund writes:
> > I'm sure we have a few places that aren't that careful, but I would hope
> > it's
> > not a large number. Are you thinking of specific "patterns" we've repeated
> > all
> > over, or just a few cases you recall?
>
> I
Andres Freund writes:
> On 2023-01-27 15:06:37 -0500, Tom Lane wrote:
>> There are a lot of places where we're implicitly relying on
>> cross-compilation-unit optimizations NOT happening, because the code isn't
>> adequately decorated with memory barriers and the like.
> We have a fallback compil
Hi,
On 2023-01-27 15:06:37 -0500, Tom Lane wrote:
> There are a lot of places where we're implicitly relying on
> cross-compilation-unit optimizations NOT happening, because the code isn't
> adequately decorated with memory barriers and the like.
We have a fallback compiler barrier implementation
Hi,
On 2023-01-27 10:05:09 -0700, João Paulo Labegalini de Carvalho wrote:
> I am investigating the benefits of different profile-guided optimizations
> (PGO) and link-time optimizations (LTO) versus binary optimizers (e.g.
> BOLT) for applications such as PostgreSQL.
>
> I am facing issues when
=?UTF-8?Q?Jo=C3=A3o_Paulo_Labegalini_de_Carvalho?=
writes:
> I am facing issues when applying LTO to PostgreSQL as the produced binary
> seems broken (the server dies quickly after it has started). This is
> definitely a compiler bug, but I was wondering if anyone here have
> experimented with L
Hi,
We have implemented LTO in PostGIS's build system a couple releases ago. It
definitely gives +10% on heavy maths. Unfortunately we did not manage to
get it running under FreeBSD because of default system linker issues so we
had to hide it under --with-lto switch which we recommend to everyone.
