Re: [RFC PATCH 1/8] AQM: Use CAKE as default qdisc where appropriate instead of fq_codel

[Michael Tremer <michael.tremer@ipfire.org>]

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Hello,

It would be great if people could help me test this.

This should improve network latency massively for users with a slow connection and it should reduce CPU load for people who have a lot of throughput to handle.

I lack a sufficiently slow connection to actually see noticeable benefits over fq_codel and would like to invite everyone who can to give this all a test and let me know if things have changed for them.

Best,
-Michael

> On 2 Dec 2021, at 12:37, Michael Tremer <michael.tremer(a)ipfire.org> wrote:
> 
> This script configures CAKE as default qdisc where appropriate:
> 
> * It is not suitable to use any queue management on bridges/GRE/VTI/tun
>  interfaces.
> * On Internet-facing interfaces, CAKE is configured in "internet" mode
>  whereas on any zones except RED, it is configured in "metro" mode
> 
> Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
> ---
> config/udev/enable_codel | 65 ++++++++++++++++++++++++++++++++--------
> 1 file changed, 52 insertions(+), 13 deletions(-)
> 
> diff --git a/config/udev/enable_codel b/config/udev/enable_codel
> index 6cafd9b26..3ef9b0f59 100644
> --- a/config/udev/enable_codel
> +++ b/config/udev/enable_codel
> @@ -21,9 +21,9 @@
> #                                                                          #
> ############################################################################
> 
> -LOG_FACILITY="codel"
> +LOG_FACILITY="aqm"
> 
> -function log() {
> +log() {
> 	logger -t "${LOG_FACILITY}" $@
> }
> 
> @@ -32,19 +32,58 @@ if [ -z "${INTERFACE}" ]; then
> 	exit 1
> fi
> 
> -# Do nothing for the loopback device.
> -[ "${INTERFACE}" = "lo" ] && exit 0
> -
> case "${ACTION}" in
> 	add|register)
> -		# Change root qdisc to use fq_codel.
> -		/sbin/tc qdisc add root dev ${INTERFACE} fq_codel
> -		ret=$?
> -
> -		if [ ${ret} -eq 0 ]; then
> -			log "Codel AQM has been enabled on '${INTERFACE}'."
> -		else
> -			log "Codel AQM could not be enabled on '${INTERFACE}'. Error code: ${ret}"
> +		TYPE="$(</sys/class/net/${INTERFACE}/type)"
> +
> +		# Detect bridges
> +		if [ -d "/sys/class/net/${INTERFACE}/bridge" ]; then
> +			TYPE="bridge"
> +		fi
> +
> +		args=()
> +
> +		# Configure some useful defaults depending on the interface
> +		case "${INTERFACE},${TYPE}" in
> +			# Ignore loopback
> +			lo,*)
> +				exit 0
> +				;;
> +
> +			# Ignore tun
> +			tun*)
> +				exit 0
> +				;;
> +
> +			# Ignore GRE/VTI
> +			*,778|*,768)
> +				exit 0
> +				;;
> +
> +			# Ignore bridges
> +			*,bridge)
> +				exit 0
> +				;;
> +
> +			# Handle RED PPPoE (default to VDSL2)
> +			ppp*,512)
> +				args+=( "cake" "internet" "pppoe-ptm" "ack-filter" )
> +				;;
> +
> +			# Treat any other interfaces as "Ethernet"
> +			red*,*)
> +				args+=( "cake" "internet" "ethernet" )
> +				;;
> +
> +			# All other interfaces are locally connected
> +			*)
> +				args+=( "cake" "ethernet" "metro" )
> +				;;
> +		esac
> +
> +		# Change root qdisc to use cake
> +		if ! tc qdisc replace root dev "${INTERFACE}" "${args[@]}"; then
> +			log "Could not configure qdisc on ${INTERFACE} with parameters ${args[@]}"
> 			exit ${ret}
> 		fi
> 		;;
> -- 
> 2.30.2
>