MSP Serial Throughput

Overview

Depends on:

• FC type
• Physical interface

Typically one gets around 60 - 100 MSP message round-trips per second. F7 will be faster than F4 and UART is usually faster than VCP (e.g. on F4, VCP c. 60 msp/sec, F4, UART c. 100 msp/sec),

Transport dependency

The above assumes that the transport is capable of 115200 baud speeds and is reliable, even if the FC cannot provide anything like the theoretical speed for small "request / response" messages.

If one uses a slower, less reliable transport then speeds will drop, and some packets may even be lost.

Example

F4 processor, LoRa telemetry radios (Ebyte E220 in transparent mode with "ground" speed 115200 and "air" speed 62500)

mwp in polling / HID mode i.e. includingMSP_SET_RAW_RC. poll-timeout at the default (900).

Note that the link is not 100% reliable, over the period of an hour, 7 messages (out of 61666) are lost (no reply received).

The table below shows the average, minimum and maximum round trip times. The trip time is from sending the message to having received the reply. The Drop column indicates if one or more messages was lost and was retried.

Message	Average(s)	Minimum(s)	Maximum(s)	Count	Drop
MSP:IDENT	0.049	0.049	0.049	1
MSP:API_VERSION	0.052	0.052	0.052	1
MSP:NAME	0.055	0.055	0.055	1
MSP2:INAV_MIXER	0.055	0.055	0.055	1
MSP:SET_RAW_RC	0.062	0.056	1.034	20571	Y
MSP:BOARD_INFO	0.058	0.058	0.058	1
MSP:FC_VARIANT	0.054	0.054	0.054	1
MSP:FEATURE	0.053	0.053	0.053	1
MSP:BLACKBOX_CONFIG	0.055	0.055	0.055	1
MSP:FC_VERSION	0.051	0.051	0.051	1
MSP2:COMMON_SET_TZ	0.045	0.045	0.045	1
MSP:BUILD_INFO	0.061	0.061	0.061	1
MSP2:COMMON_SERIAL_CONFIG	0.080	0.080	0.080	1
MSP:BOXIDS	0.068	0.068	0.068	1
MSP:WP_GETINFO	0.053	0.053	0.053	1
MSP:BOX	0.056	0.056	0.056	1
MSP2:COMMON_SETTING	0.170	0.129	0.244	6
MSP2:INAV_STATUS	0.058	0.052	1.004	4973	Y
MSP2:SAFEHOME	0.055	0.050	0.067	8
MSP2:FW_APPROACH	0.060	0.055	0.071	8
MSP2:GEOZONE	0.058	0.056	0.060	5
MSP2:GEOZONE_VERTEX	0.054	0.050	0.060	15
MSP2:ANALOG2	0.061	0.055	0.099	1245
MSP:NAV_STATUS	0.054	0.046	0.090	4977
MSP:RAW_GPS	0.057	0.051	0.971	4976	Y
MSP:COMP_GPS	0.054	0.045	1.009	4975	Y
MSP:GPSSTATISTICS	0.058	0.052	0.092	4974
MSP:WP	0.060	0.052	1.065	4974	Y
MSP:ATTITUDE	0.054	0.046	1.021	4972	Y
MSP:ALTITUDE	0.053	0.048	0.087	4971

Notes:

• Message names are mwp's approximation to INAV's official nomenclature
• MSP:WP timed-out twice.
• Generated with HID enabled mwp 25.04.27:

  MWP_MSP_RC="-f boxer.txt" mwp --debug-flags 4
  

• Reducing poil-timeout (e.g. to 100) might be considered for this radio.

Final summary (note 17.1 msp/sec):

13:49:06.505215 3604.437s, rx 1127690b, tx 1218551b, (313b/s, 338b/s) to 7 wait 0, avg poll loop 87 ms messages 61666 msg/s 17.1