Re: [PATCHv8 02/34] lib/vdso: make do_hres and do_coarse as __always_inline

Vincenzo Frascino
2020-01-10T11:47:43Z

On 1/10/20 11:42 AM, Thomas Gleixner wrote:
> Vincenzo Frascino <vincenzo.frascino-5wv7dgnIgG8@public.gmane.org> writes:
>> On 11/12/19 1:26 AM, Dmitry Safonov wrote:
>>> +» » vd·=·&vd[CS_HRES_COARSE];
>>> +out_hres:
>>> +» » return·do_hres(vd,·clock,·ts);
>>> » }·else·if·(msk·&·VDSO_COARSE)·{
>>> » » do_coarse(&vd[CS_HRES_COARSE],·clock,·ts);
>>> » » return·0;
>>> » }·else·if·(msk·&·VDSO_RAW)·{
>>> -» » return·do_hres(&vd[CS_RAW],·clock,·ts);
>>> +» » vd·=·&vd[CS_RAW];
>>> +» » /*·goto·allows·to·avoid·extra·inlining·of·do_hres.·*/
>>> +» » goto·out_hres;
>>
>> What is the performance impact of "goto out_hres"?
>
> On x86 it's invisible at least in my limited testing.

On arm64 as well based on mine as well. Shall we keep the code more readable
here (without goto)?

>
> Thanks,
>
> tglx
>

--
Regards,
Vincenzo