Fix rclpy async executor sleep. (backport #1661)#1676
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The python asyncio sleep allows for a bit of clock resolution sloppiness (see https://github.com/python/cpython/blob/50476a7e87926cf6a9ea978943c4a3d5d771c95f/Lib/asyncio/base_events.py#L2036) which means that the asyncio sleep can actually wake up *before* the requested amount of time has passed. This is mostly a problem on Windows, where the tick time is 15ms, and we see some tests in rclpy fail a number of times there before eventually succeeding. There are 2 ways we can fix this: either by making the tests accept some slop, or by making the rclpy AsyncClock sleep go back to sleep if it wakes up early. The former is more like Python's asyncio, the latter is more like the rclcpp RCL_TIME sleep. I chose to go with the latter because this is a robotics framework and waking up too early is as bad as waking up too late. But everyone has to deal with the latter situation *anyway*, so it seems more predictable to always sleep at least the requested amount of time. That's what this commit does. Signed-off-by: Chris Lalancette <clalancette@gmail.com> (cherry picked from commit 1e5e267)
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fujitatomoya
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Jun 2, 2026
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Could you look into the executor failures in windows CI: https://ci.ros2.org/job/ci_windows/28235/testReport/(root)/projectroot/test_executor/ |
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Description
The python asyncio sleep allows for a bit of clock resolution sloppiness (see https://github.com/python/cpython/blob/50476a7e87926cf6a9ea978943c4a3d5d771c95f/Lib/asyncio/base_events.py#L2036) which means that the asyncio sleep can actually wake up before the requested amount of time has passed. This is mostly a problem on Windows, where the tick time is 15ms, and we see some tests in rclpy fail a number of times there before eventually succeeding.
There are 2 ways we can fix this: either by making the tests accept some slop, or by making the rclpy AsyncClock sleep go back to sleep if it wakes up early. The former is more like Python's asyncio, the latter is more like the rclcpp RCL_TIME sleep.
I chose to go with the latter because this is a robotics framework and waking up too early is as bad as waking up too late. But everyone has to deal with the latter situation anyway, so it seems more predictable to always sleep at least the requested amount of time. That's what this commit does.
Is this user-facing behavior change?
No.
Did you use Generative AI?
Yes, Claude Opus 4.7
Additional Information
N/A
This is an automatic backport of pull request #1661 done by Mergify.