Re: [qemu-s390x] [Qemu-devel] [PATCH] include/fpu/softfloat: Fix compilation with Clang on s390x

[Emilio G. Cota]

On Wed, Jan 16, 2019 at 07:33:28 +0100, Thomas Huth wrote:
> On 2019-01-15 21:05, Emilio G. Cota wrote:
> > On Tue, Jan 15, 2019 at 16:01:32 +0000, Alex Bennée wrote:
> >> Ahh I should have mentioned we already have the technology for this ;-)
> >>
> >> If you build the fpu/next tree on a s390x you can then run:
> >>
> >>   ./tests/fp/fp-bench f64_div
> >>
> >> with and without the CONFIG_128 path. To get an idea of the real world
> >> impact you can compile a foreign binary and run it on a s390x system
> >> with:
> >>
> >>   $QEMU ./tests/fp/fp-bench f64_div -t host
> >>
> >> And that will give you the peak performance assuming your program is
> >> doing nothing but f64_div operations. If the two QEMU's are basically in
> >> the same ballpark then it doesn't make enough difference. That said:
> > 
> > I think you mean here `tests/fp/fp-bench -o div -p double', otherwise
> > you'll get the default op (-o add).
> 
> I tried that now, too, and -o div -p double does not really seem to
> exercise this function at all.

You can check what is being called then with perf record/report.

                E.