Slow WiFi download speed

mrr · 23 April 2023 10:25

Looking for some advice troubleshooting my slow wifi connection.

I have a desktop and a raspberrypi both connected to a router via wifi.
When downloading a file from a remote server (rsync via ssh in case it’s important), raspberrypi gets about 5-5.5 MB/s, but on the PC the speed won’t go above 500 kB/s.

Things I have tried without any noticeable difference:

Switching from wpa_supplicant to iwd
Using 2.4Ghz instead of 5Ghz on the PC (pi uses 2.4GHz)
Fiddling with iwlwifi settings:

cat /etc/modprobe.d/iwlwifi.conf                                                                                                                                                                                     
options iwlwifi swcrypto=1 11n_disable=1 bt_coex_active=0

Anything else I can check to troubleshoot this?

 inxi -N                                                                                                                                                                   
 Network:
  Device-1: Intel Dual Band Wireless-AC 3168NGW [Stone Peak] driver: iwlwifi
  Device-2: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet
    driver: r8168

lshw -C network

  *-network                 
       description: Wireless interface
       product: Dual Band Wireless-AC 3168NGW [Stone Peak]
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:29:00.0
       logical name: wlan0
       version: 10
       serial: 9c:29:76:c1:cf:32
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=6.1.25-1-MANJARO firmware=29.198743027.0 3168-29.ucode ip=192.168.1.77 latency=0 link=yes multicast=yes wireless=IEEE 802.11
       resources: irq:82 memory:fc600000-fc601fff

inxi -Fazy                                                                                                                                                                                                                  

System:
  Kernel: 6.1.25-1-MANJARO arch: x86_64 bits: 64 compiler: gcc v: 12.2.1
    parameters: BOOT_IMAGE=/boot/vmlinuz-6.1-x86_64
    root=UUID=41842a12-6b2a-4b25-b1af-237f1d287cf0 rw quiet apparmor=1
    security=apparmor udev.log_priority=3
  Desktop: KDE Plasma v: 5.27.4 tk: Qt v: 5.15.8 wm: kwin_x11 vt: 1 dm: SDDM
    Distro: Manjaro Linux base: Arch Linux
Machine:
  Type: Desktop Mobo: Micro-Star model: B550M PRO-VDH WIFI (MS-7C95) v: 1.0
    serial: <superuser required> UEFI: American Megatrends LLC. v: 2.A0
    date: 03/16/2022
CPU:
  Info: model: AMD Ryzen 5 5600X bits: 64 type: MT MCP arch: Zen 3+ gen: 4
    level: v3 note: check built: 2022 process: TSMC n6 (7nm) family: 0x19 (25)
    model-id: 0x21 (33) stepping: 0 microcode: 0xA201016
  Topology: cpus: 1x cores: 6 tpc: 2 threads: 12 smt: enabled cache:
    L1: 384 KiB desc: d-6x32 KiB; i-6x32 KiB L2: 3 MiB desc: 6x512 KiB L3: 32 MiB
    desc: 1x32 MiB
  Speed (MHz): avg: 2727 high: 3700 min/max: 2200/4650 boost: enabled
    scaling: driver: acpi-cpufreq governor: schedutil cores: 1: 3599 2: 3700
    3: 2877 4: 2200 5: 2200 6: 2200 7: 3600 8: 2200 9: 2200 10: 2876 11: 2880
    12: 2200 bogomips: 88827
  Flags: avx avx2 ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm
  Vulnerabilities:
  Type: itlb_multihit status: Not affected
  Type: l1tf status: Not affected
  Type: mds status: Not affected
  Type: meltdown status: Not affected
  Type: mmio_stale_data status: Not affected
  Type: retbleed status: Not affected
  Type: spec_store_bypass mitigation: Speculative Store Bypass disabled via
    prctl
  Type: spectre_v1 mitigation: usercopy/swapgs barriers and __user pointer
    sanitization
  Type: spectre_v2 mitigation: Retpolines, IBPB: conditional, IBRS_FW,
    STIBP: always-on, RSB filling, PBRSB-eIBRS: Not affected
  Type: srbds status: Not affected
  Type: tsx_async_abort status: Not affected
Graphics:
  Device-1: NVIDIA GP108 [GeForce GT 1030] vendor: ASUSTeK driver: nvidia
    v: 530.41.03 alternate: nouveau,nvidia_drm non-free: 530.xx+
    status: current (as of 2023-03) arch: Pascal code: GP10x process: TSMC 16nm
    built: 2016-21 pcie: gen: 3 speed: 8 GT/s lanes: 4 bus-ID: 2b:00.0
    chip-ID: 10de:1d01 class-ID: 0300
  Display: x11 server: X.Org v: 21.1.8 compositor: kwin_x11 driver: X:
    loaded: nvidia gpu: nvidia display-ID: :0 screens: 1
  Screen-1: 0 s-res: 3840x1080 s-dpi: 92 s-size: 1060x301mm (41.73x11.85")
    s-diag: 1102mm (43.38")
  Monitor-1: DVI-D-0 pos: left res: 1920x1080 hz: 60 dpi: 93
    size: 527x296mm (20.75x11.65") diag: 604mm (23.8") modes: N/A
  Monitor-2: HDMI-0 pos: primary,right res: 1920x1080 hz: 60 dpi: 93
    size: 527x296mm (20.75x11.65") diag: 604mm (23.8") modes: N/A
  API: OpenGL v: 4.6.0 NVIDIA 530.41.03 renderer: NVIDIA GeForce GT
    1030/PCIe/SSE2 direct-render: Yes
Audio:
  Device-1: NVIDIA GP108 High Definition Audio vendor: ASUSTeK
    driver: snd_hda_intel bus-ID: 3-2:3 v: kernel chip-ID: 045e:070f pcie:
    class-ID: 0300 gen: 3 speed: 8 GT/s lanes: 4 bus-ID: 2b:00.1
    chip-ID: 10de:0fb8 class-ID: 0403
  Device-2: AMD Starship/Matisse HD Audio vendor: Micro-Star MSI
    driver: snd_hda_intel v: kernel pcie: gen: 4 speed: 16 GT/s lanes: 16
    bus-ID: 2d:00.4 chip-ID: 1022:1487 class-ID: 0403
  Device-3: Microsoft LifeChat LX-3000 Headset type: USB
    driver: hid-generic,snd-usb-audio,usbhid
  API: ALSA v: k6.1.25-1-MANJARO status: kernel-api with: aoss
    type: oss-emulator tools: alsamixer,amixer
  Server-1: JACK v: 1.9.22 status: off tools: N/A
  Server-2: PipeWire v: 0.3.70 status: off with: pipewire-media-session
    status: active tools: pw-cli
  Server-3: PulseAudio v: 16.1 status: active with: pulseaudio-jack
    type: module tools: pacat,pactl
Network:
  Device-1: Intel Dual Band Wireless-AC 3168NGW [Stone Peak] driver: iwlwifi
    v: kernel pcie: gen: 1 speed: 2.5 GT/s lanes: 1 bus-ID: 29:00.0
    chip-ID: 8086:24fb class-ID: 0280
  IF: wlan0 state: up mac: <filter>
  Device-2: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet
    vendor: Micro-Star MSI driver: r8168 v: 8.050.03-NAPI modules: r8169 pcie:
    gen: 1 speed: 2.5 GT/s lanes: 1 port: f000 bus-ID: 2a:00.0
    chip-ID: 10ec:8168 class-ID: 0200
  IF: enp42s0 state: down mac: <filter>
Bluetooth:
  Device-1: Intel Wireless-AC 3168 Bluetooth type: USB driver: btusb v: 0.8
    bus-ID: 1-9:4 chip-ID: 8087:0aa7 class-ID: e001
  Report: rfkill ID: hci0 rfk-id: 1 state: up address: see --recommends
Drives:
  Local Storage: total: 2.73 TiB used: 1.87 TiB (68.5%)
  SMART Message: Unable to run smartctl. Root privileges required.
  ID-1: /dev/nvme0n1 maj-min: 259:0 vendor: Crucial model: CT1000P1SSD8
    size: 931.51 GiB block-size: physical: 512 B logical: 512 B speed: 31.6 Gb/s
    lanes: 4 type: SSD serial: <filter> rev: P3CR013 temp: 30.9 C scheme: GPT
  ID-2: /dev/sda maj-min: 8:0 vendor: Seagate model: ST2000DM008-2FR102
    size: 1.82 TiB block-size: physical: 4096 B logical: 512 B speed: 6.0 Gb/s
    type: HDD rpm: 7200 serial: <filter> rev: 0001 temp: 28.0 C
Partition:
  ID-1: / raw-size: 931.01 GiB size: 915.33 GiB (98.32%)
    used: 529.02 GiB (57.8%) fs: ext4 dev: /dev/nvme0n1p3 maj-min: 259:2
  ID-2: /boot/efi raw-size: 512 MiB size: 511 MiB (99.80%)
    used: 6.8 MiB (1.3%) fs: vfat dev: /dev/nvme0n1p1 maj-min: 259:1
Swap:
  Alert: No swap data was found.
Sensors:
  System Temperatures: cpu: N/A mobo: N/A
  Fan Speeds (RPM): cpu: 1082 fan-2: 0 fan-3: 1045 fan-4: 1021 fan-5: 0
    fan-6: 0 fan-7: 0 fan-8: 0 fan-9: 0 fan-10: 0
Info:
  Processes: 306 Uptime: 15m wakeups: 0 Memory: 31.27 GiB
  used: 5.11 GiB (16.3%) Init: systemd v: 252 default: graphical
  tool: systemctl Compilers: gcc: 12.2.1 clang: 15.0.7 Packages: pm: pacman
  pkgs: 1914 libs: 492 tools: pamac,yay pm: appimage pkgs: 0 pm: flatpak
  pkgs: 0 Shell: Zsh v: 5.9 default: Bash v: 5.1.16 running-in: konsole
  inxi: 3.3.26

megavolt · 23 April 2023 11:19

Hello @mrr

Maybe first check if the problem is really the Wi-Fi. Since you have 2 devices in your local network, maybe try this:

pamac install iperf3

apt install iperf3

Start a server on one computer: iperf3 --server
Run a speed test on the second computer: iperf3 --client 192.xxx.xxx.xxx

That is a raw bandwidth test. Keep sure port 5201 is open on the server.

Also please check the availabe bandwidth:

iw dev <device> link

<device> could be wlp2s0. Check ip a.

mrr · 23 April 2023 19:38

HI @megavolt

Thanks for your suggestions. I ran both tests but tbh have trouble interpreting the results.

First iperf

PC server / raspberrypi client

[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  22.0 MBytes  18.5 Mbits/sec    0             sender
[  5]   0.00-10.44  sec  20.7 MBytes  16.6 Mbits/sec                  receiver

[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.44  sec  20.7 MBytes  16.6 Mbits/sec                  receiver

the other way - PC client / pi server

[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  32.0 MBytes  26.9 Mbits/sec    0             sender
[  5]   0.00-10.06  sec  30.1 MBytes  25.1 Mbits/sec                  receiver

[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.06  sec  30.1 MBytes  25.1 Mbits/sec                  receiver

The other command:

iw dev wlan6 link                                                                                                                                                                                                            ✔ 
Connected to ... (on wlan6)
        SSID: ...
        freq: 5240
        RX: 37965263 bytes (34092 packets)
        TX: 37125554 bytes (37913 packets)
        signal: -62 dBm
        rx bitrate: 54.0 MBit/s
        tx bitrate: 54.0 MBit/s

        bss flags:      short-slot-time
        dtim period:    3
        beacon int:     100

Does anything stand out?

megavolt · 23 April 2023 20:22

@mrr Seems to be pretty normal. It can theoretically use a bandwidth of 54Mbit (~6Mbyte), what is 802.11g. Take into account the correction layer, which reduces the bandwidth anyway. A signal strength of -65dBm is not perfect, but sufficient. So my guess is that Wi-Fi is not the problem here.

mrr · 23 April 2023 20:46

Thanks.
Unfortunately right now I don’t have an Ethernet cable long enough to test wired connection. Will have to order it first.

Is there anything else I can check in the meantime?

leledumbo · 23 April 2023 23:10

Just to be sure, post these commands’ result:

$ iw reg get

$ modinfo iwlwifi | grep parm

cscs · 24 April 2023 00:06

You know this disables that right? The N band that is.
A more useful option is 11n_disable=8

Do not be confused with the option name, when the value is set to 8 it does not disable anything but re-enables transmission antenna aggregation.

Now the power settings for intel wireless are in a seperate module … depending on the age it is either iwlmvm or for older cards iwldvm.

You can configure the power cheme like so:
/etc/modprobe.d/iwlmvm.conf

options iwlmvm power_scheme=1

Where the schemes are as follows:

1	Always Active
2	Balanced
3	Low-power

Theres also more general power saving;

iw dev wlan0 set power_save off

Oh and depending on your region you may want to look at setting it. More info can be found here:
Network configuration/Wireless - ArchWiki

mrr · 24 April 2023 19:51

global
country 00: DFS-UNSET
        (755 - 928 @ 2), (N/A, 20), (N/A), PASSIVE-SCAN
        (2402 - 2472 @ 40), (N/A, 20), (N/A)
        (2457 - 2482 @ 20), (N/A, 20), (N/A), AUTO-BW, PASSIVE-SCAN
        (2474 - 2494 @ 20), (N/A, 20), (N/A), NO-OFDM, PASSIVE-SCAN
        (5170 - 5250 @ 80), (N/A, 20), (N/A), AUTO-BW, PASSIVE-SCAN
        (5250 - 5330 @ 80), (N/A, 20), (0 ms), DFS, AUTO-BW, PASSIVE-SCAN
        (5490 - 5730 @ 160), (N/A, 20), (0 ms), DFS, PASSIVE-SCAN
        (5735 - 5835 @ 80), (N/A, 20), (N/A), PASSIVE-SCAN
        (57240 - 63720 @ 2160), (N/A, 0), (N/A)

phy#0 (self-managed)
country GB: DFS-UNSET
        (2402 - 2437 @ 40), (6, 22), (N/A), AUTO-BW, NO-HT40MINUS, NO-80MHZ, NO-160MHZ
        (2422 - 2462 @ 40), (6, 22), (N/A), AUTO-BW, NO-80MHZ, NO-160MHZ
        (2447 - 2482 @ 40), (6, 22), (N/A), AUTO-BW, NO-HT40PLUS, NO-80MHZ, NO-160MHZ
        (5170 - 5190 @ 80), (6, 22), (N/A), NO-OUTDOOR, AUTO-BW, IR-CONCURRENT, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5190 - 5210 @ 80), (6, 22), (N/A), NO-OUTDOOR, AUTO-BW, IR-CONCURRENT, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5210 - 5230 @ 80), (6, 22), (N/A), NO-OUTDOOR, AUTO-BW, IR-CONCURRENT, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5230 - 5250 @ 80), (6, 22), (N/A), NO-OUTDOOR, AUTO-BW, IR-CONCURRENT, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5250 - 5270 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5270 - 5290 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5290 - 5310 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5310 - 5330 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5490 - 5510 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5510 - 5530 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5530 - 5550 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5550 - 5570 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5570 - 5590 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5590 - 5610 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5610 - 5630 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5630 - 5650 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5650 - 5670 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5670 - 5690 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5690 - 5710 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5710 - 5730 @ 80), (6, 22), (0 ms), DFS, AUTO-BW, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5735 - 5755 @ 80), (6, 22), (N/A), AUTO-BW, IR-CONCURRENT, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5755 - 5775 @ 80), (6, 22), (N/A), AUTO-BW, IR-CONCURRENT, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5775 - 5795 @ 80), (6, 22), (N/A), AUTO-BW, IR-CONCURRENT, NO-HT40MINUS, NO-160MHZ, PASSIVE-SCAN
        (5795 - 5815 @ 80), (6, 22), (N/A), AUTO-BW, IR-CONCURRENT, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN
        (5815 - 5835 @ 20), (6, 22), (N/A), AUTO-BW, IR-CONCURRENT, NO-HT40MINUS, NO-HT40PLUS, NO-80MHZ, NO-160MHZ, PASSIVE-SCAN

parm:           debug:debug output mask (uint)
parm:           swcrypto:using crypto in software (default 0 [hardware]) (int)
parm:           11n_disable:disable 11n functionality, bitmap: 1: full, 2: disable agg TX, 4: disable agg RX, 8 enable agg TX (uint)
parm:           amsdu_size:amsdu size 0: 12K for multi Rx queue devices, 2K for AX210 devices, 4K for other devices 1:4K 2:8K 3:12K (16K buffers) 4: 2K (default 0) (int)
parm:           fw_restart:restart firmware in case of error (default true) (bool)
parm:           nvm_file:NVM file name (charp)
parm:           uapsd_disable:disable U-APSD functionality bitmap 1: BSS 2: P2P Client (default: 3) (uint)
parm:           enable_ini:0:disable, 1-15:FW_DBG_PRESET Values, 16:enabled without preset value defined,Debug INI TLV FW debug infrastructure (default: 16)
parm:           bt_coex_active:enable wifi/bt co-exist (default: enable) (bool)
parm:           led_mode:0=system default, 1=On(RF On)/Off(RF Off), 2=blinking, 3=Off (default: 0) (int)
parm:           power_save:enable WiFi power management (default: disable) (bool)
parm:           power_level:default power save level (range from 1 - 5, default: 1) (int)
parm:           disable_11ac:Disable VHT capabilities (default: false) (bool)
parm:           remove_when_gone:Remove dev from PCIe bus if it is deemed inaccessible (default: false) (bool)
parm:           disable_11ax:Disable HE capabilities (default: false) (bool)

mrr · 24 April 2023 19:54

I did not, to be honest. I was trying various things I found online.

Tried that yesterday, no luck.

Currently my config looks like this

$ cat /etc/modprobe.d/iwlwifi.conf
options iwlwifi 11n_disable=8 swcrypto=0 bt_coex_active=0 power_save=0
options iwlmvm power_scheme=1

mrr · 24 April 2023 19:58

I think I have set this in the past. Still tried again, no luck.

leledumbo · 25 April 2023 02:22

mrr:

    freq: 5240
    ...
    signal: -62 dBm
    rx bitrate: 54.0 MBit/s
    tx bitrate: 54.0 MBit/s
    ...
(5230 - 5250 @ 80), (6, 22), (N/A), NO-OUTDOOR, AUTO-BW, IR-CONCURRENT, NO-HT40PLUS, NO-160MHZ, PASSIVE-SCAN

Looks odd, the rate is like 20Mhz, probably that AUTO-BW plays. Still, you should get at least 2-2.5 MBps, not 500 kBps. Another iwlwifi magic maybe? This driver has quite some upstream bugs, indeed. May as well change the card to something like QCA9377.

mrr · 25 April 2023 19:52

And I’m guessing there’s no alternative driver?

Thanks, I can try this. Any particular cards/vendors? So far I only find laptop adapters with this chipset.

I’m also waiting for Ethernet cable to be delivered to test wired connection as someone has suggested in this thread. Will report once I have the results.

mrr · 25 April 2023 20:10

Ok, this is interesting. I’ve tried enabling debug as per Enable full debugging output in the iwlwifi driver - CONFIG_IWLWIFI_DEBUG - - kernelconfig.io

After a restart my wifi got super slow, barely even working, and dmesg printed this every few seconds

[  178.104540] iwlwifi 0000:29:00.0: Queue 11 is active on fifo 1 and stuck for 10000 ms. SW [9, 164] HW [9, 164] FH TRB=0x0c010b018
[  178.105589] iwlwifi 0000:29:00.0: Microcode SW error detected.  Restarting 0x2000000.
[  178.105752] iwlwifi 0000:29:00.0: Start IWL Error Log Dump:
[  178.105753] iwlwifi 0000:29:00.0: Transport status: 0x0000004A, valid: 6
[  178.105755] iwlwifi 0000:29:00.0: Loaded firmware version: 29.198743027.0 3168-29.ucode

Reverting the debug change didn’t help, even after a restart.

I switched from 5GHz to 2.4GHz and suddenly the speed has improved significantly - now I’m getting between 4.5 and 5 MB/s.
Go figure.

mrr · 28 April 2023 10:29

As expected wired connection is noticeably faster (I’m getting around 6MB/s).
At the same time my wifi got slower again (about 2.5MB/s) and less stable.
Looks like I’ll be getting a new wireless card soon as I’m done dealing with this iwlwifi rubbish.