On 08/09/2020, 1:01, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I wonder what version of gcc you intend this for. AFAICS, older
> gcc versions lack this flag at all, while newer ones have it on
> by default.
(previously sent private reply, sorry)
The moutline-atomics flag showed substantial enough improvements
that it has been backported to GCC 9, 8 and there is a gcc-7 branch in
the works.
Ubuntu has integrated this in 20.04, Amazon Linux 2 supports it,
with other distributions including Ubuntu 18.04 and Debian on the way.
all distributions, including the upcoming Ubuntu with GCC-10, have
moutline-atomics turned off by default.