#!/bin/bash
# SPDX-License-Identifier: BSD-3-Clause
# Copyright (C) 2020 - 2023 Intel Corporation
#
# Attempt a basic setup of adaptive receive flow steering
# also known as aRFS.  aRFS will automatically at runtime
# use ntuple rules to direct receive traffic to the same
# rx queue (matched by queue number) as was used for the
# application that was transmitting. Most useful for
# TCP workloads and latency sensitive TCP connections.
#
# typical usage is (as root):
# set_arfs -s flow_entries eth1 <eth2> <eth3>
#
# to get help:
# set_arfs

usage()
{
	echo
	echo "Usage: $0 [-s flow_entries] <interface> ..."
	echo "  Options: "
	echo "    -s            number of socket flow entries"
	echo "  Examples:"
	echo "    $0 eth1 eth2            # eth1 and eth2 use default flow_entries"
	echo "    $0 -s flow_entries eth1 # eth1 use specified flow_entries"
	echo
	exit 1
}

# offer some help
if [ "$1" == "-h" ] || [ "$1" == "--help" ]; then
	usage
	exit 1
fi

# if -s and a value specified, then use them.
if [ "$1" == "-s" ]; then
	FLOW_ENTRIES=$2
	shift
	shift
fi

# append the interfaces listed to the string with spaces
while [ "$#" -ne "0" ] ; do
	IFACES+=" $1"
	shift
done

# for now the user must specify interfaces
if [ -z "$IFACES" ]; then
	usage
	exit 1
fi

# provide a default flow num value, typically 2048 per queue
# is useful, but if there are many queues then maybe a smaller
# value per-queue is good enough.
if [ -z "$FLOW_ENTRIES" ]; then
	FLOW_ENTRIES=32768
fi

set_arfs()
{
	echo $FLOW_ENTRIES > /proc/sys/net/core/rps_sock_flow_entries
	echo -n "done: "
	grep -H . /proc/sys/net/core/rps_sock_flow_entries
	for IFACE in $IFACES; do
		QDIR="/sys/class/net/$IFACE/queues"
		QUEUES=`ls -1 -d $QDIR/rx-*`
		QUEUES_COUNT=`ls -1 -d $QDIR/rx-* | wc -l`
		sockTrack=$((FLOW_ENTRIES / QUEUES_COUNT))
		if [ -z `ls $QDIR/rx-0/rps_flow_cnt` ]; then
			echo "ERROR: aRFS is not supported on $IFACE"
			exit 2
		fi
		n=0
		for i in $QUEUES; do
			echo $sockTrack > $i/rps_flow_cnt
			echo -n "Queue $((n++)) done: "
			grep -H . $i/rps_flow_cnt
		done
	done
}

set_arfs