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--- searchwing-pi-datarate [2020/01/08 21:38]
beckmanf [http transfer time for wifi] rate computed
+++ searchwing-pi-datarate [2021/11/17 22:35]
wf68spef
@@ Line 1: / Line 1: @@
-===== Raspberry Pi data transfer rate test =====
+===== Raspberry Pi Zero data transfer rate test =====
 The Raspberry Pi stores the images which are collected during flight. After the plane landed, the images are retrieved from the Pi. The least impact with respect to water sealing would be a wireless transfer via Wifi or Bluetooth. For completeness I also test the transfer rate via USB configured as RNDIS network device. As a seperate topic I look into the transfer rate of the SD Card.
@@ Line 493: / Line 493: @@
   * Placement: Pi Zero and Laptop placed 10cm above router.
   * data ammount: 540 MByte
+  * ** Laptop and Raspberry Pi share the same Wifi channel => Each packet goes from Pi to AP and from AP to Laptop. => Congestion on the Wifi Channel. **
 === wget ===
@@ Line 506: / Line 507: @@
 ==== Results ====
+  * The Laptop and the Pi should not be connected via a single 2.4 GHz access point as laptop and Pi share the same Wifi channel. This results in 50% throughput reduction (see Julians 2.5 MB/s for wget).
+  * The transfer rate via wget on an undisturbed 2.4 GHz wifi channel is **5 MB/s**. (Only Pi connected to AP, No other stations use this channel). This 40 MBit/s throughput on http level compares well to the maximum 65 MBit/s wifi data rate of the Pi Zero W.
+  * ssh transfer is limited by CPU load on the Pi for encryption and results in 1.8 MB/s for Wifi.
+  * Short Guard Interval setting could possibly increase the the raw wifi rate from 65 MBit/s to 72 MBit/s.
@@ Line 514: / Line 519: @@
+===== Pi4/CM4 data transfer rate test =====
+  * Fritzbox 7520
+  * CM4 5Ghz Wifi
+  * Laptop T14 via Ethernet
+==== pi4 config ====
+<code>
+pi@testi:~ $ iw dev
+phy#0
+	Unnamed/non-netdev interface
+		wdev 0x2
+		addr de:a6:32:fe:85:b0
+		type P2P-device
+		txpower 31.00 dBm
+	Interface wlan0
+		ifindex 3
+		wdev 0x1
+		addr dc:a6:32:fe:85:b0
+		ssid DrMartinRouterKing
+		type managed
+		channel 64 (5320 MHz), width: 80 MHz, center1: 5290 MHz
+		txpower 31.00 dBm
+</code>
+==== iperf measurements via WLAN ====
+=== Datatransfer Pi4 -> Laptop ===
+<code>
+➜  /tmp iperf3 -s
+-----------------------------------------------------------
+Server listening on 5201 (test #1)
+-----------------------------------------------------------
+Accepted connection from 192.168.178.29, port 54534
+[  5] local 192.168.178.20 port 5201 connected to 192.168.178.29 port 54536
+[ ID] Interval           Transfer     Bitrate
+[  5]   0.00-1.00   sec  9.14 MBytes  76.7 Mbits/sec
+[  5]   1.00-2.00   sec  10.8 MBytes  90.9 Mbits/sec
+[  5]   2.00-3.00   sec  10.9 MBytes  91.1 Mbits/sec
+[  5]   3.00-4.00   sec  10.8 MBytes  90.9 Mbits/sec
+[  5]   4.00-5.00   sec  10.9 MBytes  91.5 Mbits/sec
+[  5]   5.00-6.00   sec  10.3 MBytes  86.2 Mbits/sec
+[  5]   6.00-7.00   sec  9.21 MBytes  77.3 Mbits/sec
+[  5]   7.00-8.00   sec  10.9 MBytes  91.1 Mbits/sec
+[  5]   8.00-9.00   sec  10.8 MBytes  90.7 Mbits/sec
+[  5]   9.00-10.00  sec  10.9 MBytes  91.5 Mbits/sec
+[  5]  10.00-10.01  sec   103 KBytes  89.2 Mbits/sec
+- - - - - - - - - - - - - - - - - - - - - - - - -
+[ ID] Interval           Transfer     Bitrate
+[  5]   0.00-10.01  sec   105 MBytes  87.8 Mbits/sec                  receiver
+-----------------------------------------------------------
+Server listening on 5201 (test #2)
+-----------------------------------------------------------
+^Ciperf3: interrupt - the server has terminated
+</code>
+=== Datatransfer Pi4 <- Laptop ===
+<code>
+➜  /tmp iperf3 -c 192.168.178.29
+iperf3: error - unable to connect to server: Connection refused
+➜  /tmp iperf3 -c 192.168.178.29
+Connecting to host 192.168.178.29, port 5201
+[  5] local 192.168.178.20 port 40318 connected to 192.168.178.29 port 5201
+[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
+[  5]   0.00-1.00   sec  5.21 MBytes  43.7 Mbits/sec   24   24.0 KBytes
+[  5]   1.00-2.00   sec  4.57 MBytes  38.4 Mbits/sec   32   22.6 KBytes
+[  5]   2.00-3.00   sec  4.75 MBytes  39.8 Mbits/sec   35   38.2 KBytes
+[  5]   3.00-4.00   sec  5.11 MBytes  42.8 Mbits/sec   36   28.3 KBytes
+[  5]   4.00-5.00   sec  4.51 MBytes  37.9 Mbits/sec   24   31.1 KBytes
+[  5]   5.00-6.00   sec  5.11 MBytes  42.8 Mbits/sec   31   21.2 KBytes
+[  5]   6.00-7.00   sec  5.23 MBytes  43.8 Mbits/sec   23   35.4 KBytes
+[  5]   7.00-8.00   sec  5.46 MBytes  45.8 Mbits/sec   27   21.2 KBytes
+[  5]   8.00-9.00   sec  4.99 MBytes  41.8 Mbits/sec   20   35.4 KBytes
+[  5]   9.00-10.00  sec  4.63 MBytes  38.9 Mbits/sec   41   19.8 KBytes
+- - - - - - - - - - - - - - - - - - - - - - - - -
+[ ID] Interval           Transfer     Bitrate         Retr
+[  5]   0.00-10.00  sec  49.6 MBytes  41.6 Mbits/sec  293             sender
+[  5]   0.00-10.00  sec  49.3 MBytes  41.4 Mbits/sec                  receiver
+iperf Done.
+</code>