[openwrt/openwrt] bcm53xx: enable & setup packet steering

[LEDE Commits]

rmilecki pushed a commit to openwrt/openwrt.git, branch openwrt-22.03:
https://git.openwrt.org/e291e49da3e04bd1cd707958512e1834c18c54cd

commit e291e49da3e04bd1cd707958512e1834c18c54cd
Author: Rafał Miłecki <rafal at milecki.pl>
AuthorDate: Fri Jun 10 10:51:23 2022 +0200

    bcm53xx: enable & setup packet steering
    
    Packet steering can improve NAT masquarade performance on Northstar by
    40-50%. It makes reaching 940-942 Mb/s possible on BCM4708 (and
    obviously BCM47094 too). Add scripts setting up the most optimal
    Northstar setup.
    
    Below are testing results for running iperf TCP traffic from LAN to WAN.
    They were used to pick up golden values.
    
    ┌──────────┬──────────┬────────────────────┬────────────────────┐
    │   eth0   │  br-lan  │ flow_offloading=0  │ flow_offloading=1  │
    │          │          ├─────────┬──────────┼─────────┬──────────┤
    │ rps_cpus │ rps_cpus │ BCM4708 │ BCM47094 │ BCM4708 │ BCM47094 │
    ├──────────┼──────────┼─────────┼──────────┼─────────┼──────────┤
    │        0 │        0 │     387 │      671 │     707 │      941 │
    │        0 │        1 │     343 │      576 │     705 │      941 │
    │        0 │        2 │   ✓ 574 │    ✓ 941 │     704 │      940 │
    │        1 │        0 │     320 │      549 │     561 │      941 │
    │        1 │        1 │     327 │      551 │     553 │      941 │
    │        1 │        2 │     523 │    ✓ 940 │     559 │      940 │
    │        2 │        0 │     383 │      652 │   ✓ 940 │      941 │
    │        2 │        1 │     448 │      754 │   ✓ 942 │      941 │
    │        2 │        2 │     404 │      655 │   ✓ 941 │      941 │
    └──────────┴──────────┴─────────┴──────────┴─────────┴──────────┘
    
    Above tests were performed with all eth0 interrupts handled by CPU0.
    Setting "echo 2 > /proc/irq/38/smp_affinity" was tested on BCM4708 but
    it didn't increased speeds (just required different steering):
    
    ┌──────────┬──────────┬───────────┐
    │   eth0   │  br-lan  │ flow_offl │
    │   rx-0   │   rx-0   │ oading=0  │
    │ rps_cpus │ rps_cpus │  BCM4708  │
    ├──────────┼──────────┼───────────┤
    │        0 │        0 │       384 │
    │        0 │        1 │     ✓ 574 │
    │        0 │        2 │       348 │
    │        1 │        0 │       383 │
    │        1 │        1 │       412 │
    │        1 │        2 │       448 │
    │        2 │        0 │       321 │
    │        2 │        1 │       520 │
    │        2 │        2 │       327 │
    └──────────┴──────────┴───────────┘
    
    Signed-off-by: Rafał Miłecki <rafal at milecki.pl>
    (cherry picked from commit fcbd39689ebfef20c62fe3882d51f3af765e8028)
---
 .../bcm53xx/base-files/etc/init.d/fastnetwork      | 44 ++++++++++++++++++++++
 .../base-files/etc/uci-defaults/05_packet_steering |  3 ++
 2 files changed, 47 insertions(+)

diff --git a/target/linux/bcm53xx/base-files/etc/init.d/fastnetwork b/target/linux/bcm53xx/base-files/etc/init.d/fastnetwork
new file mode 100755
index 0000000000..1999d13707
--- /dev/null
+++ b/target/linux/bcm53xx/base-files/etc/init.d/fastnetwork
@@ -0,0 +1,44 @@
+#!/bin/sh /etc/rc.common
+
+START=25
+USE_PROCD=1
+
+start_service() {
+	reload_service
+}
+
+service_triggers() {
+	procd_add_reload_trigger "network"
+	procd_add_reload_trigger "firewall"
+	procd_add_reload_interface_trigger "lan"
+}
+
+reload_service() {
+	local packet_steering="$(uci -q get network. at globals[0].packet_steering)"
+	local num_cpus="$(grep -c "^processor.*:" /proc/cpuinfo)"
+	local flow_offloading="$(uci -q get firewall. at defaults[0].flow_offloading)"
+	local flow_offloading_hw="$(uci -q get firewall. at defaults[0].flow_offloading_hw)"
+
+	# Any steering on 1 CPU (BCM47081) worsens network performance
+	[ "$num_cpus" != 2 ] && return
+
+	[ "$packet_steering" != 1 ] && {
+		echo 0 > /sys/class/net/br-lan/queues/rx-0/rps_cpus
+		echo 0 > /sys/class/net/eth0/queues/rx-0/rps_cpus
+		return
+	}
+
+	if [ ${flow_offloading_hw:-0} -gt 0 ]; then
+		# HW offloading
+		echo 0 > /sys/class/net/br-lan/queues/rx-0/rps_cpus
+		echo 0 > /sys/class/net/eth0/queues/rx-0/rps_cpus
+	elif [ ${flow_offloading:-0} -gt 0 ]; then
+		# SW offloading
+		# br-lan setup doesn't seem to matter for offloading case
+		echo 2 > /sys/class/net/eth0/queues/rx-0/rps_cpus
+	else
+		# Default
+		echo 2 > /sys/class/net/br-lan/queues/rx-0/rps_cpus
+		echo 0 > /sys/class/net/eth0/queues/rx-0/rps_cpus
+	fi
+}
diff --git a/target/linux/bcm53xx/base-files/etc/uci-defaults/05_packet_steering b/target/linux/bcm53xx/base-files/etc/uci-defaults/05_packet_steering
new file mode 100644
index 0000000000..98c9497815
--- /dev/null
+++ b/target/linux/bcm53xx/base-files/etc/uci-defaults/05_packet_steering
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+uci set network. at globals[0].packet_steering="1"