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

[Thomas Gleixner]

Vincenzo Frascino <vincenzo.frascino@xxxxxxx> writes:
> On 1/10/20 11:42 AM, Thomas Gleixner wrote:
>>>> +Â Â /*ÂgotoÂallowsÂtoÂavoidÂextraÂinliningÂofÂdo_hres.Â*/
>>>> +Â Â gotoÂout_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)?

The delta patch below makes it readable again and also avoids the double
inlining. Quick testing shows no difference.

Thanks,

        tglx

8<---------------
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -98,17 +98,15 @@ static __maybe_unused int
 	msk = 1U << clock;
 	if (likely(msk & VDSO_HRES)) {
 		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) {
 		vd = &vd[CS_RAW];
-		/* This goto avoids extra inlining of do_hres. */
-		goto out_hres;
+	} else {
+		return -1;
 	}
-	return -1;
+	return do_hres(vd, clock, ts);
 }
 
 static __maybe_unused int