FS#4221 - R7800 poor download rate when client connects with 100FD #9202
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I experience the same low download/upload speeds when there is LAN traffic. |
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After lots of tests - here is the problem completely reproducible using iperf3 to create LAN traffic between LAN clients. In my case I run iperf3 (with a predefined throughput of 60Mbps) between a Laptop connected at 100Mbps! (this is the culprit) and PC connected at 1000Mbps. The result - the PC can only download/upload from/to WAN at really low speeds. |
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I have to add that two compulsory conditions should be met at the same time in order to reproduce the WAN performance drop. A client connected at 100Mbps (let's call it "Problem Client") and a LAN traffic between the "Problem Client" and any other device connected to LAN by cable. |
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@sppmasterspp what we should really test is if the original firmware also suffer from the same problem. Can you that simple test? It's just to have a direction if internally they fixed the bug and we are just missing the workaround on our code |
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@Ansuel What I've been able to test so far is this: |
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@Ansuel @quarkysg |
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I've posted the exact steps to reproduce/trigger the bug. |
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@quarkysg and @Ansuel |
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@quarkysg @Ansuel |
Ansuel
added
target/ipq806x
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@Ansuel @quarkysg No such loss of performance can be observed when only Gigabit clients are connected to the gigabit switch. Instead we achieve Gigabit Full Duplex speeds as can be expected - simultaneous 1Gbps download and 1Gbps upload WAN/LAN performance no matter of the LAN traffic. |
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I'm starting to think this is a hw limitation...
Il Dom 5 Giu 2022, 01:10 sppmasterspp ***@***.***> ha scritto:
… @Ansuel <https://github.com/Ansuel> @quarkysg
<https://github.com/quarkysg>
I've tried this with several gigabit routers - Netgear R7800, TP-Link
WDR4300, Belkin RT3200. With all of them the results are completely
repeatable using the same bench test setup. These three routers are based
on different SoC's. The hardware is different but I see almost the same
WAN/LAN performance degradation with only negligible variances.
I've tried several OpenWRT versions with default and custom
configurations. The issue is present on all stock firmwares I've tried too
and they are based on older OpenWRT code.
No such loss of performance can be observed when only Gigabit clients are
connected to the gigabit switch. Instead we achieve Gigabit Full Duplex
speeds as can be expected - simultaneous 1Gbps download and 1Gbps upload
WAN/LAN performance no matter of the LAN traffic.
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@Ansuel |
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@Ansuel @quarkysg |
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Only affects one direction. My 1000/400 connection turns into 1000/100. Maybe is some "switch qos" bug. Or cpu port. |
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@nikito7 |
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@Ansuel @quarkysg |
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As I posted on the forum, it's quite possible that having Ethernet flow control enabled on the wired ports will cause such issues. It seems to be enabled by default, on Linksys E8450 at least, but you really don't want it enabled, especially when mixed speed devices are connected to the switch ports. |
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Disabling Flow Control of the built-in R7800 switch gives full WAN speed but breaks LAN transfers. So this isn't a solution yet to the WAN/LAN performance issue. |
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@Ansuel |
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@sppmasterspp nice that we are noticing a pattern with flow control... Could be that there is a problem with flow control and how it's handled by the switch... Also this is half or full duplex? |
With the help of @quarkysg I've disabled the Flow Control of the single port of the R7800 switch (where the PC server is connected to). I think it's set at full duplex. Unfortunately I put the Belkin RT3200 at service and currently I'm unable to repeat the same tests with it when the Flow Control of the switch is disabled. |
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So the current hack is to disable flow control for 100mbps interesting stuff.... I wonder if this is related to the trottle values... Do you remember having lots of dropped packet? Or the connection was just slow? Your belkin is at service now so you have the bug right? Can you post some stats from both your switch and the router ? (ethtool -S < the port lan1 lan2 wan.... >) @quarkysg can you help me with this? I would love to test some values for the flow control threshold Currently my 2 idea are
I would first investigate the threshold by setting a stupid high value (and low value) and check if that makes a difference. |
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@Ansuel @quarkysg |
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ethtool -S lan1 if for example you have connected it to lan1 port... |
For this stats the router is mostly idling with 4 WLAN clients. |
Do you mean |
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no.... swconfig |
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Any command to run? |
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swconfig list should give you the switch present on your router |
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can you give me the help output? |
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This will reduce network speed but will enable stats After 2-3 sec run the show command again to confirm |
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swconfig sorry |
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and after 2-3 sec |
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ok and the port that is 100mbps is? can't see any in the stats log |
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It's LAN port 1 on the router (is it 4 on the switch). Currently there is a TP-Link Gigabit switch connected to it. I have three 100Mbps devices connected to the TP-Link switch. |
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@sppmasterspp does this traffic makes sense to you? (the low rx bytes) (notice the very high pause frame received...) Are we sure this is not just a problem with some devices that does stupid thing? I mean the pause frame are received not emitted by the switch... |
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I've connected a laptop to port 2 (LAN2 on the router switch) enabled the Flow Control on the PC NIC connected at LAN4 (on the router) and run iperf3 between the PC (LAN4) and the Laptop 100Mbps (LAN2) and started WAN speed test on the PC. |
I have a switch TP-Link and there are connected three 100Mbps devices to it. Two Cable TV set-top boxes from ISP. They are AnndroidTV boxes and one smart TV. |
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This stats is when the Laptop is connected at 1Gbps. How can I return the router switch settings to the previous values. |
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You just enable stat polling nothing more... unless you have 1gbps network you won't notice any... Anyway to disable but it would be usefull to get some more stats data |
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I'll leave it running with stats enabled. |
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After running for a few hours |
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Some more data |
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@Ansuel |
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Do you have same issue on previous kernel 5.4.x? |
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Yes I have the same issue with 5.4.x kernels. |
Ernie63:
Netgear Nighthawk X4S R7800 with OpenWrt 21.02.1 freshly installed
ISP line is 250/25. Wan port is 1G (auto).
Steps to reproduce:
Laptop connected on LAN-side with 1G (auto): Ookla speedtest is 250/25.
Laptop connected on LAN-side with 100FD: Ookla speedtest is only 30/25.
This performance degration only occurs, when the R7800 is routing and natting the traffic.
"Switched only" traffic inside the LAN is not affected.
With stock ROM the download rate is as expected:
Laptop connected on LAN-side with 100FD: Ookla speedtest is 80/25.
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