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

Rui Ueyama via llvm-dev llvm-dev at lists.llvm.org
Thu Nov 17 10:31:45 PST 2016

On Thu, Nov 17, 2016 at 10:27 AM, Renato Golin <renato.golin at linaro.org>

> On 17 November 2016 at 17:50, Mehdi Amini via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
> > It depends on the use-case: with ThinLTO we scale linearly with the
> number
> > of physical cores. When you get over the number of physical cores you
> still
> > get some improvements, but that’s no longer linear.
> Indeed, in HT, cores have two execution units on the same cache/bus
> line, so memory access is likely to be contrived. Linkers are memory
> hungry, which add to the I/O bottleneck which makes most of the gain
> disappear. :)
> Furthermore, the FP unit is also shared among the ALUs, so
> FP-intensive code does not make good use of HT. Not the case, here,
> though.

We literally have no variables of type float or double in LLD. It would
work fine on 486SX. :)
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