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FS#1527 - AR8327 low throughput #1324

Open aparcar opened 6 years ago

aparcar commented 6 years ago

eripek:

Affected devices and versions of LEDE/OpenWRT: 1x TL-WR1043NDv2 - OpenWrt SNAPSHOT, r6800-52ba576 3x TL-WR1043NDv2 - LEDE 17.01.4 (stable) 1x TL-WDR3600 - LEDE 17.01.4 (stable)

All of the above devices use AR8327 rev as their switch: [ 0.881815] switch0: Atheros AR8327 rev. 4 switch registered on ag71xx-mdio.0

Steps to reproduce: A) iperf clients 3x TL-WR1043NDv2 connected by their WAN port, that is configured to act as vlan trunk port only. 1x TL-WDR3600 connected by it's WAN port, that is configured to act as vlan trunk port only. 1x TL-WR1043NDv2 connected by it's port no 4, that is configured to act as vlan trunk port only. B) iperf server 1 (192.168.0.1) C) iperf server 2 (192.168.0.11) D) four gigabit ethernet easysmart/websmart switches with 1,5GB+ throughput, each, in between A,B,C.

  1. Any A against B over cable - as an example: Client connecting to 192.168.0.1, TCP port 5001 TCP window size: 43.8 KByte (default)

    [ 3] local 192.168.0.75 port 35102 connected with 192.168.0.1 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 179 MBytes 150 Mbits/sec

  2. C against B over each of the 4 devices in D: Client connecting to 192.168.0.1, TCP port 5001 TCP window size: 85.0 KByte (default)

    [ 3] local 192.168.0.11 port 56228 connected with 192.168.0.1 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 1.09 GBytes 938 Mbits/sec

Each of the TP-Links is using switch-only, no WAN, no NAT, but INPUT-iptables for their respective vlans, so another test of one of the A-devices against B w/o iptables:

Client connecting to 192.168.0.1, TCP port 5001 TCP window size: 43.8 KByte (default)

[ 3] local 192.168.0.242 port 45976 connected with 192.168.0.1 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 213 MBytes 179 Mbits/sec

It seems, that devices containing AR8327 rev4 wont achieve more than 1/5 of the specified nominal LAN speeds, when acting as an endpoint.

Further observations: WLAN clients won't exceed 25-30 Mbit/s, when using one of the trunked vlans. (WLAN client iwlwifi, Centrino N 2230, e.g. in either 40 or 20 MHz against A-devices in 802.11n WDS AP mode).

Since this is no WAN to LAN scenario, (missing) HWNAT cannot be involved. Why is the switch performance below expectations? Is this a hw issue or a driver problem?

aparcar commented 6 years ago

eripek:

Probably a duplicate of #891