fix delays from rospy long-running callbacks #12
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dandedrick
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Long-running callbacks in rospy can cause extreme amounts of buffering resulting in unnecessary delay, essentially ignoring the queue_size setting (ros#1901). This can already be somewhat mitigated by setting buff_size to be larger than the amount of data that could be buffered by a long running callback. However, setting buff_size to a correct value is not possible for the user of the API if the amount of time in the callback or the amount of data that would be transmitted is unknown. Also, even with a correct buff_size and a queue_size of 1, the received data may still be the oldest of all data transmitted while the callback was running. Fix the delays in such cases by running callbacks in a separate thread. The receive_loop then calls recv() concurrently with the long running callback, enforcing queue_size as new data is received. This fixes the latency in the data when queue_size is set to be similar to roscpp. This fixes ros#1901
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Long-running callbacks in rospy can cause extreme amounts of buffering
resulting in unnecessary delay, essentially ignoring the queue_size
setting (ros#1901). This can already be somewhat mitigated by setting
buff_size to be larger than the amount of data that could be buffered
by a long running callback. However, setting buff_size to a correct
value is not possible for the user of the API if the amount of time in
the callback or the amount of data that would be transmitted is
unknown. Also, even with a correct buff_size and a queue_size of 1, the
received data may still be the oldest of all data transmitted while the
callback was running.
Fix the delays in such cases by running callbacks in a separate thread.
The receive_loop then calls recv() concurrently with the long running
callback, enforcing queue_size as new data is received. This fixes the
latency in the data when queue_size is set to be similar to roscpp.
This fixes ros#1901
This change is