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

[Thomas Huth <thuth@redhat.com>]

On 2019-01-16 18:08, Alex Bennée wrote:
> 
> Thomas Huth <thuth@redhat.com> writes:
> 
>> 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.
> 
> How do you mean? It should do because by default it should be calling
> the softfloat implementations.

I've added a puts("hello") into the udiv_qrnd() function. When I then
run "fp-bench -o div -p double", it only prints out "hello" a single
time, so the function is only called once during the whole test.

 Thomas