On 2022-01-29 04:55, Larry Finger wrote:
On 1/28/22 16:13, Schüll, Daniel wrote:
After upgrading to the 5.15 kernel I noticed a drop in throughput when
using my wifi dongle.
I'm using a TP-Link TL-WN725N-v2 (USB ID: 0bda:8179).
On the 5.15 kernel I was only able to get around 30 MBit/s in download
(using google's speedtest).
After downgrading back to the 5.13 kernel I was back to 95 MBit/s I
used to have (close to the max from my ISP).
A bit of research revealed, that you did a major overhaul of the
r8188eu driver in 5.15.
I then compiled the old rtl8188eu driver from the 5.13 sources for
5.15, loaded it on 5.15 and was able to get 95 MBit/s again.
Finally I also tried the newest version of the new r8188eu driver
(Commit fa78315452) on 5.15, but still only got 30 MBits/s.
All test used the same location of AP and dongle and were done
multiple times, so influence from other wifi devices is negligible.
Seeing that the issue is fixable by using an other driver module on
the same kernel, it seems very likely,
that the issue is in the driver and not in the setup or other kernel
changes.
Is the throughput a known regression?
Daniel,
This throughput regression is not known to me. I have not been very
involved with the changes being made to r8188eu, but I do test it
regularly to ensure that it can still make a connection. With my
tests, I do not recall getting a speed over 40-45 Mbps connecting to a
local LibreSpeed instance connected to my AP via a 1 GHz wired line.
As I recall, I never have gotten anything near 95 Mbps.
I generated a 5.13 kernel, and it did not get over 30 Mbps. I get the
same download speed from Speedtest.net. As my up connection only runs
at 12 Mbps, that is what I always get when using an external
connection.
that's interesting. Can you confirm that you are using the 40 MHz
frequency range?
My AP is an AVM FritzBox!3390. In its menu I can see that the wifi
dongle is using the following configuration: 2.4 GHz, n, 40 MHz, WPA2, 1
x 1
With the one antenna of the rtl8188eu and 40 MHz the theoretical limit
is 150 Mbps.
I also retested with a local iperf server on the fritzbox.
This is where things get strange. With the new r8188eu driver iperf over
TCP gives me ~60 Mbps.
While google's speedtest still gives me only ~30 Mbps (I also tested
various other in-browser tests with same results).
With the old driver rtl8188eu again I get ~95 Mbps over iperf and
in-browser.
Regards,
Daniel
