Richard Biener wrote:
> On Fri, Nov 3, 2017 at 6:38 AM, Andrew Pinski <apin...@cavium.com> wrote:
> > On Fri, Nov 3, 2017 at 12:11 AM, Wilco Dijkstra <wilco.dijks...@arm.com>
> > wrote:
> >> The Arm backend sets the default sched-pressure algorithm to
> >> SCHED_PRESSURE_MODEL. Benchmarking on AArch64 shows this
> >> speeds up floating point performance on SPEC - eg. CactusBSSN improves
> >> by ~16%. The gains are mostly due to less spilling, so enable this on
> >> AArch64
> >> by default.
> >>
>>> OK for commit?
> >
> > I am ok with this from my point of view. The rs6000, arm and s390
> > back-ends all enable the same way. I suspect all RISC targets should
> > enable this way too.
>
> I think all OOO execution capable CPUs should. Ideally this wouldn't be
> a choice between two models but the scheduler would take into account
> register pressure anyways. Or we should always schedule with sched-pressure
> during first scheduling.
Of the 6 targets which use -fsched-pressure, 5 prefer SCHED_PRESSURE_MODEL,
so we could just make that the default (nds32 is the only exception, but it
has 32 registers so that should not be an issue).
This also fits nicely with my patches to improve GCC settings to be more
optimal.
Wilco
