[Bug] 100% CPU from LOG_REQUEST_LIST

[dakejahl]

Describe the bug

When receiving a LOG_REQUEST_LIST message the CPU will peg at 100% in mavlink_receiver. I did a little bit of debugging and it appears that this is happening inside of the _mavlink_log_handler.send() function within the mavlink_receiver.cpp main loop.

_init_list_helper(): takes 300ms
_get_entry(): takes variable amount of time depending on how many logs you have. It takes roughly 5 seconds to send out 171 log entries, at which point mavlink_receiver is blocking and hogging CPU.

To Reproduce

Send LOG_REQUEST_LIST

Expected behavior

Doesn't hog CPU

Screenshot / Media

Flight Log

https://review.px4.io/plot_app?log=e8d4f344-0f1d-4358-afbe-498d235ac71c

Software Version

main

Flight controller

ark_fmu-v6x_default

Vehicle type

None

How are the different components wired up (including port information)

No response

Additional context

No response

[muramura]

I am using PIXHAWK6X-RT.
It reboots after downloading a 370 megabyte log file.
The transfer rate was 900 kilobytes/second, so I set the maximum bytes from 256 to 1024 kilobytes and it did not reboot.

The PIXHAWK6X-RT has a 1 GHz MPU.

CPU load is 50% during download, usually in the 26% range.