[PATCH 3/3] resolv: Optimize inet_ntop

[Collin Funk]

Adhemerval Zanella <adhemerval.zanella@linaro.org> writes:

> The performance results on aarch64 Neoverse1 with gcc 14.2.1:
>
> * master
>
> aarch64-linux-gnu-master$ ./benchtests/bench-inet_ntop_ipv4
>   "inet_ntop_ipv4": {
>    "workload-ipv4-random": {
>     "duration": 1.43067e+09,
>     "iterations": 8e+06,
>     "reciprocal-throughput": 178.572,
>     "latency": 179.096,
>     "max-throughput": 5.59997e+06,
>     "min-throughput": 5.58359e+06
>    }
> aarch64-linux-gnu-master$ ./benchtests/bench-inet_ntop_ipv6
>   "inet_ntop_ipv6": {
>    "workload-ipv6-random": {
>     "duration": 1.68539e+09,
>     "iterations": 4e+06,
>     "reciprocal-throughput": 421.307,
>     "latency": 421.388,
>     "max-throughput": 2.37357e+06,
>     "min-throughput": 2.37311e+06
>    }
>   }
>
> * patched
>
> aarch64-linux-gnu$ ./benchtests/bench-inet_ntop_ipv4
>   "inet_ntop_ipv4": {
>    "workload-ipv4-random": {
>     "duration": 1.06324e+09,
>     "iterations": 4.4e+07,
>     "reciprocal-throughput": 24.1509,
>     "latency": 24.178,
>     "max-throughput": 4.14063e+07,
>     "min-throughput": 4.13599e+07
>    }
> aarch64-linux-gnu$ ./benchtests/bench-inet_ntop_ipv6
>   "inet_ntop_ipv6": {
>    "workload-ipv6-random": {
>     "duration": 1.08476e+09,
>     "iterations": 2.4e+07,
>     "reciprocal-throughput": 45.2794,
>     "latency": 45.1174,
>     "max-throughput": 2.20851e+07,
>     "min-throughput": 2.21644e+07
>    }
>   }
>
> Checked on aarch64-linux-gnu and x86_64-linux-gnu.
> ---
>  resolv/inet_ntop.c | 134 +++++++++++++++++++++++++++++----------------
>  1 file changed, 87 insertions(+), 47 deletions(-)

This part of the patch series looks good to me. So:

Reviewed-by: Collin Funk <collin.funk1@gmail.com>

I see similar results as well:

    $ grep '^model name' /proc/cpuinfo | sed 1q
    model name	: AMD Ryzen 7 3700X 8-Core Processor
    $ gcc --version | sed 1q
    gcc (GCC) 15.1.1 20250521 (Red Hat 15.1.1-2)
    # Pre patch
    $ cat benchtests/bench.out 
    {"timing_type": "hp_timing",
     "functions": {
      "inet_ntop_ipv4": {
       "workload-ipv4-random": {
        "duration": 3.94723e+09,
        "iterations": 8e+06,
        "reciprocal-throughput": 492.274,
        "latency": 494.534,
        "max-throughput": 2.03139e+06,
        "min-throughput": 2.0221e+06
       }
      }
    ,
      "inet_ntop_ipv6": {
       "workload-ipv6-random": {
        "duration": 4.67659e+09,
        "iterations": 4e+06,
        "reciprocal-throughput": 1164.13,
        "latency": 1174.17,
        "max-throughput": 859010,
        "min-throughput": 851668
       }
      }
    
     }
    }
    # Post patch
    $ cat benchtests/bench.out 
    {"timing_type": "hp_timing",
     "functions": {
      "inet_ntop_ipv4": {
       "workload-ipv4-random": {
        "duration": 3.67214e+09,
        "iterations": 8.4e+07,
        "reciprocal-throughput": 43.7862,
        "latency": 43.6457,
        "max-throughput": 2.28382e+07,
        "min-throughput": 2.29118e+07
       }
      }
    ,
      "inet_ntop_ipv6": {
       "workload-ipv6-random": {
        "duration": 3.9483e+09,
        "iterations": 3.6e+07,
        "reciprocal-throughput": 109.916,
        "latency": 109.434,
        "max-throughput": 9.09786e+06,
        "min-throughput": 9.13793e+06
       }
      }
    
     }
    }
    
Thanks,
Collin