# Re: \[RFC PATCH bpf-next 1/2\] bpf: add bpf\_strncmp helper

- From: Hou Tao \<hidden\>
- Date: 2021-11-08 14:09:07 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/11/7785536
- Thread: https://ratatoskr.run/netdev/2021/11/7785452/t.md

```text
Hi,

On 11/7/2021 4:32 AM, Alexei Starovoitov wrote:
> On Sat, Nov 6, 2021 at 1:07 PM Andrii Nakryiko
> [ref] wrote:
snip
>>> I was thinking whether the proto could be:
>>> long bpf_strncmp(const char *s1, u32 s1_sz, const char *s2)
>>> but I think your version is better though having const string as 1st arg
>>> is a bit odd in normal C.
>> Why do you think it's better? This is equivalent to `123 == x` if it
>> was integer comparison, so it feels like bpf_strncmp(s, sz, "blah") is
>> indeed more natural. No big deal, just curious what's better about it.
> Only that helper implementation has two less register moves.
> which makes it 51%/49% win for me.
> .
I agree with Andrii that bpf_strncmp(s, sz, "blah") is more nature. I can run
some simple benchmarks to show whether or not the difference matters.

Regards,
Tao.
```