topic_tools: throttling when rostime jump backward #1397
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Should there be some kind of threshold for the jump, or at least a flag to disable this behaviour? I'm thinking a default that the jump-back-in-time logic is only triggered for a delta > 1s or something. Admittedly, I may be grasping at straws here, but I'm imagining a scenario where two separate machines are publishing the same topic with slightly offset clocks, or even with the same clock but network lag which causes the messages to interleave. |
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If time moves backwards it's definitely an event. Realistically you should never have two clocks publishing, that's basically guarenteed to cause bad behavior due to interleaving. And non-monotonic clocks will wreak havoc hear and elsewhere.
This is the same logic that tf users to clear the buffer: https://github.com/ros/geometry2/blob/melodic-devel/tf2_ros/src/transform_listener.cpp#L105
tools/topic_tools/src/throttle.cpp
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| @@ -126,6 +126,11 @@ void in_cb(const ros::MessageEvent<ShapeShifter>& msg_event) | |||
| now.fromSec(ros::WallTime::now().toSec()); | |||
| else | |||
| now = ros::Time::now(); | |||
| if (g_last_time > now) | |||
| { | |||
| ROS_WARN("Detected jump back in time."); | |||
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This should state what it's doing, not just that it detected. Something like "Detected jump back in time, resetting throttle period to now for ***."
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@mikepurvis @tfoote Thank you very much for your review!
@tfoote I updated the message. Please check. 👍
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lgtm, we don't really have a way to address the throttle instance so at least it's know that some throttle will be updated. |
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Thank you for the patch. |
Closes #1396