AP_HAL_SITL: add packet loss and delay to each uart #25775
+419
−10
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
robertlong13
changed the title
robertlong13
force-pushed
the
pr/uart_delays
branch
2 times, most recently
from
478ba77 to
21f0e16
Compare
robertlong13
force-pushed
the
pr/uart_delays
branch
2 times, most recently
from
dc71606 to
1b031c4
Compare
This would sometimes happen when initiating a connection when using high simulated latency values when the queue would suddenly flush to the buffer.
robertlong13
force-pushed
the
pr/uart_delays
branch
from
1b031c4 to
a619a9e
Compare
|
I did a similar (ish) thing for the ELRS sim here: #26663. The key difference is that it does all the limiting in the "radio" sim rather in the UART driver. |
tridge
requested changes
May 20, 2024
| if (_sitl && _sitl->uart_byte_loss_pct > 0) { | ||
| if (fabsf(rand_float()) < _sitl->uart_byte_loss_pct.get() * 0.01 * size) { | ||
| lost_byte = 1; | ||
| // simulate whole packet loss rate per uart driver |
There was a problem hiding this comment.
it would be nice to break this out to a separate function
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
I need a way to simulate:
(I am working on a redundant link manager plugin for Mission Planner that tries to intelligently select the "best" link to the aircraft.)
Before this, you could only simulate single-byte losses, and the setting applied to all serial ports. This switches to dropping full packets (I may extend this to partial packets at some point, to catch any issues caused by dropped data not aligning with packet boundaries, but I'm trying to figure out how to do that without introducing a million parameters), and it allows you to set the drop rate per serial port. In conjunction with a lua script, this could be used to cause burst losses for multiple seconds or could steadily increase the loss rate as you fly further from home.
I also added two queues to delay packets for a period of time both in and out. This is to simulate, for example, the ping time of a 4G link or satcom. This could even be used with a script that randomly sets this high and then low to simulate a TCP link that locks up for some period of time, then delivers all that data all at once when it comes back.
I have included a simple example script for an RF link, a cell link, and a hypothetical satellite device. Here's a screen of flying this aircraft in Mission Planner with all three links:
Here's a little animation of me testing that the latency works two-ways. Three instances of Mission Planner running on three different links. The left has no delay, and the two on the right have a delay of 500ms both ways. 500ms after I click the button on the right, the status message on the left updates (because the RX latency of the SITL link receiving the AUX function command), and then 500ms after that, the status message on the right updates (because the TX latency of that SITL link)