Re: [PATCH v2] selftests/net: synchronize udpgso_bench rx and tx

[Paolo Abeni]

On Mon, 2023-10-30 at 13:40 -0400, Lucas Karpinski wrote:
> The sockets used by udpgso_bench_tx aren't always ready when
> udpgso_bench_tx transmits packets. This issue is more prevalent in -rt
> kernels, but can occur in both. Replace the hacky sleep calls with a
> function that checks whether the ports in the namespace are ready for
> use.
> 
> Suggested-by: Paolo Abeni <pabeni@xxxxxxxxxx>
> Signed-off-by: Lucas Karpinski <lkarpins@xxxxxxxxxx>
> ---
> https://lore.kernel.org/all/t7v6mmuobrbucyfpwqbcujtvpa3wxnsrc36cz5rr6kzzrzkwtj@toz6mr4ggnyp/
> 
> Changelog v2: 
> - applied synchronization method suggested by Pablo
> - changed commit message to code 
> 
>  tools/testing/selftests/net/udpgro.sh         | 27 ++++++++++++++-----
>  tools/testing/selftests/net/udpgro_bench.sh   | 19 +++++++++++--
>  tools/testing/selftests/net/udpgro_frglist.sh | 19 +++++++++++--
>  3 files changed, 54 insertions(+), 11 deletions(-)
> 
> diff --git a/tools/testing/selftests/net/udpgro.sh b/tools/testing/selftests/net/udpgro.sh
> index 0c743752669a..04792a315729 100755
> --- a/tools/testing/selftests/net/udpgro.sh
> +++ b/tools/testing/selftests/net/udpgro.sh
> @@ -24,6 +24,22 @@ cleanup() {
>  }
>  trap cleanup EXIT
>  
> +wait_local_port_listen()
> +{
> +	local port="${1}"
> +
> +	local port_hex
> +	port_hex="$(printf "%04X" "${port}")"
> +
> +	local i

Minor nit: I think the code would be more readable, if you will group
the variable together:

	local port="${1}"
	local port_hex
	local i

	port_hex="$(printf "%04X" "${port}")"
	# ...

> +	for i in $(seq 10); do
> +		ip netns exec "${PEER_NS}" cat /proc/net/udp* | \
> +			awk "BEGIN {rc=1} {if (\$2 ~ /:${port_hex}\$/) {rc=0; exit}} END {exit rc}" &&
> +			break
> +		sleep 0.1
> +	done
> +}

Since you wrote the same function verbatim in 3 different files, I
think it would be better place it in separate, new, net_helper.sh file
and include such file from the various callers. Possibly additionally
rename the function as wait_local_udp_port_listen.

Thanks!

Paolo