Performance gain by avoiding arguments check is very small (less then 1%).

[Sam James]

Amit <amitchoudhary0523@gmail.com> writes:

> On Tue, Sep 30, 2025, 2:23 AM Wilco Dijkstra <Wilco.Dijkstra@arm.com> wrote:
>
>  Hi Amit,
>
>  Modern compilers will optimize your example code away. You can see that
>  there are no checks at all in the main function: https://godbolt.org/z/aeeTx6zqM
>
>  Even if it wasn't optimized, it wouldn't be possible to measure any difference.
>  Running an empty main() in a loop will just measure shell overheads. Your
>  results show it takes a few million cycles per iteration, so an extra check cannot
>  be measured. What you're really measuring is the varying turbo frequency of
>  your laptop...
>
>  Benchmarking is hard, much harder than you think. It is  done by creating a
>  tight loop around any code you want to measure. You have to use inputs that
>  are representative of real usage (ideally from traces from actual workloads).
>  For timing we use a high-resolution (nano-second) timer. You can look at
>  recent benchmarks in benchtests/ that show how it should be done.
>
>  Cheers,
>  Wilco
>
> I am not going to get into any discussion because I have learned that glibc people are defensive people and they will
> defend their wrongdoings.

I think Wilco's reply was respectful and professional. It's also
accurate. I don't see it as defensive at all.

>
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