[llvm-dev] LLD: time to enable --threads by default

[Teresa Johnson via llvm-dev]

On Thu, Nov 17, 2016 at 4:11 AM, Rafael Espíndola via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> > Sounds like threading isn't beneficial much beyond the second CPU...
> > Maybe blindly creating one thread per core isn't the best plan...
>
> parallel.h is pretty simplistic at the moment. Currently it creates
> one per SMT. One per core and being lazy about it would probably be a
> good thing, but threading is already beneficial and improving
> parallel.h an welcome improvement.
>

Instead of using std::thread::hardware_concurrency (which is one per SMT),
you may be interested in using the facility I added for setting default
ThinLTO backend parallelism so that one per physical core is created,
llvm::heavyweight_hardware_concurrency() (see D25585  and r284390). The
name is meant to indicate that this is the concurrency that should be used
for heavier weight tasks (that may use a lot of memory e.g.).

Teresa


> Cheers,
> Rafael
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>



-- 
Teresa Johnson |  Software Engineer |  tejohnson at google.com |  408-460-2413
<(408)%20460-2413>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20161117/d5a15cd5/attachment.html>