Slow WiFi speed on QC9377

Thu Jan 9 11:39:45 PST 2025

Problem

I have slow WiFi speed on my Lenovo Ideapad C340-15IWL notebook running Ubuntu 24.04.1 LTS.

I reach about 30-40 Mbit/s and experience packet loss as soon as I hit that limit. It seems that this is the overall max throughput.
How I measure

To make the tests more meaningful, I am running a iperf3 server on my local PC, that is connected to the same router per Ethernet (1 Gbit/s).

iperf3 -c  192.168.2.182
Connecting to host 192.168.2.182, port 5201
[  5] local 192.168.2.111 port 54734 connected to 192.168.2.182 port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  3.00 MBytes  25.1 Mbits/sec    0   97.0 KBytes      
[  5]   1.00-2.00   sec  3.25 MBytes  27.3 Mbits/sec    0    103 KBytes      
[  5]   2.00-3.00   sec  3.38 MBytes  28.3 Mbits/sec    0    113 KBytes      
[  5]   3.00-4.00   sec  3.75 MBytes  31.5 Mbits/sec    0    164 KBytes      
[  5]   4.00-5.00   sec  3.38 MBytes  28.3 Mbits/sec    0    188 KBytes      
[  5]   5.00-6.00   sec  2.88 MBytes  24.1 Mbits/sec    0    188 KBytes      
[  5]   6.00-7.00   sec  3.75 MBytes  31.5 Mbits/sec    0    188 KBytes      
[  5]   7.00-8.00   sec  3.38 MBytes  28.3 Mbits/sec    0    147 KBytes      
[  5]   8.00-9.00   sec  3.25 MBytes  27.3 Mbits/sec    0    164 KBytes      
[  5]   9.00-10.00  sec  3.38 MBytes  28.3 Mbits/sec    0    182 KBytes      
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  33.4 MBytes  28.0 Mbits/sec    0             sender
[  5]   0.00-10.03  sec  32.8 MBytes  27.4 Mbits/sec                  receiver

My system and more info about my WiFi connection

I am connected via 5 GHz and the router is basically 4 meters away with no obstacles in front of it. The same issue exists with 2.4 GHz.
Kernel / OS version

# cat /etc/os-release

PRETTY_NAME="Ubuntu 24.04.1 LTS"
NAME="Ubuntu"
VERSION_ID="24.04"
VERSION="24.04.1 LTS (Noble Numbat)"
VERSION_CODENAME=noble
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=noble
LOGO=ubuntu-logo

# uname -a
Linux laptop 6.8.0-51-generic #52-Ubuntu SMP PREEMPT_DYNAMIC Thu Dec  5 13:09:44 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

# lspci
[...]
02:00.0 Network controller: Qualcomm Atheros QCA9377 802.11ac Wireless Network Adapter (rev 31)
[...]

iwconfig

# iwconfig (sensitive data redacted)

wlp2s0    IEEE 802.11  ESSID:"My WiFI SSID"  
          Mode:Managed  Frequency:5.5 GHz  Access Point: AA:BB:CC:DD:EE:FF  
          Tx-Power=23 dBm  
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=67/70  Signal level=-43 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:37   Missed beacon:0

ncmli device wifi list

# mcli device wifi list
IN-USE  BSSID              SSID                 MODE   CHAN  RATE        SIGNAL  BARS  SECURITY  
*       AA:BB:CC:DD:EE:FF  My WiFi SSID   Infra  100   540 Mbit/s  97      ▂▄▆█  WPA2 WPA3 

dmesg | grep ath10k

[    4.182676] ath10k_pci 0000:02:00.0: pci irq msi oper_irq_mode 2 irq_mode 0 reset_mode 0
[    4.400376] ath10k_pci 0000:02:00.0: qca9377 hw1.1 target 0x05020001 chip_id 0x003821ff sub 17aa:0901
[    4.400382] ath10k_pci 0000:02:00.0: kconfig debug 0 debugfs 1 tracing 1 dfs 0 testmode 0
[    4.400767] ath10k_pci 0000:02:00.0: firmware ver WLAN.TF.1.0-00002-QCATFSWPZ-5 api 5 features ignore-otp crc32 c3e0d04f
[    4.463619] ath10k_pci 0000:02:00.0: board_file api 2 bmi_id N/A crc32 8aedfa4a
[    4.556609] ath10k_pci 0000:02:00.0: htt-ver 3.44 wmi-op 4 htt-op 3 cal otp max-sta 32 raw 0 hwcrypto 1
[    4.620003] ath10k_pci 0000:02:00.0 wlp2s0: renamed from wlan0

What I tried

I disabled bluetooth. Issue persists.

I disabled power management. Issue persists.

I reinstalled the package "linux-firmware". Issue persists.

I disabled IPv6. Issue persists.

I changed the ath10k firmware from 6 to 5 and vice versa. Issue persists:

:/lib/firmware/ath10k/QCA9377/hw1.0# ls -la
total 896
drwxr-xr-x 2 root root   4096 Jan  9 19:35 .
drwxr-xr-x 3 root root   4096 Apr 25  2024 ..
-rw-r--r-- 1 root root   2737 Nov 29 11:50 board-2.bin.zst
-rw-r--r-- 1 root root   1215 Nov 29 11:50 board.bin.zst
-rw-r--r-- 1 root root 498888 Nov 29 11:50 firmware-5.bin.zst
-rw-r--r-- 1 root root 390717 Nov 29 11:50 firmware-sdio-5.bin.zst
-rw-r--r-- 1 root root   5222 Nov 29 11:50 notice_ath10k_firmware-5.txt.zst
lrwxrwxrwx 1 root root     52 Nov 29 11:50 notice_ath10k_firmware-6.txt.zst -> ../../QCA6174/hw3.0/notice_ath10k_firmware-6.txt.zst
lrwxrwxrwx 1 root root     32 Nov 29 11:50 notice_ath10k_firmware-sdio-5.txt.zst -> notice_ath10k_firmware-5.txt.zst

mv /lib/firmware/ath10k/QCA9377/hw1.0/firmware-6.bin.zst /root/
modprobe -r ath10k_pci
modprobe ath10k_pci

I checked if any neighbors are on the same channel as my router, but I did not find any. I also exclude this problem because on a Windows laptop I do not have this issue.

I now have no idea anymore what to check or try. Can anyone help me? Thank you very much!

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