feat(contributing): add task scheduling

[shulanbushangshu]

Description

This pr adds ''task-scheduling" in contributing

Related to: #293

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[github-actions]

Documentation URL: https://autowarefoundation.github.io/autoware-documentation/pr-282/
Modified URLs:

• https://autowarefoundation.github.io/autoware-documentation/pr-282/contributing/coding-guidelines/ros-nodes/task-scheduling/

[takam5f2]

@shulanbushangshu
Thank you for your contribution.

To my understanding, Autoware is not implemented without considering task scheduling so far. Autoware relies on task scheduling which is managed by ROS 2 and Linux. Task scheduling is one of the issue to be tackled in the future.

It is better, I think, that this section honestly tells that task scheduling is not designed and Autoware runs on a task scheduling by combination of ROS 2 and Linux kernel. "Introducing task optimized task scheduling mechanism and applying it to Autoware are one of our future work" is required statement here.

[takam5f2]

I think that there are two types of trigger for executing callback, but it is not "publish-subscribe", strictly speaking.

[takam5f2]

--recursive is not necessary.

Suggested change

	vcs import src < caret.repos --recursive
	vcs import src < caret.repos

[takam5f2]

Installation of caret for galactic should not be mentioned here, I think.

Suggested change

	source /opt/ros/galactic/setup.bash(or source /opt/ros/humble/setup.bash)
	source /opt/ros/humble/setup.bash

[sykwer]

@shulanbushangshu

Thank you for writing the first draft of the task scheduling document!

We TIER Ⅳ members are now working on scheduling issues on Linux platforms. Our opinion is that the task scheduling document should be about how to configure the settings of a kernel scheduler to run Autoware in a predictable way. Based on workload analysis and detailed analysis of the implementation of the Linux kernel, we plan to publish a specialized functionality for the task scheduling of Autoware on Linux and the documentation about it.

Additionally, we need to deal with double scheduling problems (ROS2 executer and kernel scheduler) and scheduler settings for specialized operating systems. We are also struggling with these problems. User-defined and centralized task scheduler will be developed specialized for Autoware.

As a result, we’d like to keep this document blank until the functionality as explained above become fixed.
Thanks!

[xmfcx]

Suggested change

	The software of autoware is the system of multiple nodes.In ROS2 the executor uses one or more threads of the underlying operating system to invoke the callbacks. The different type of callback has the different priority.
	In autoware,there are two types about "publish-subscribe":
	Autoware is a system made of multiple ROS2 nodes.
	In ROS2 the executor uses one or more threads of the underlying operating system to invoke the callbacks.
	Callbacks are units of work like subscription callbacks, timer callbacks, service calls, and received client responses.
	The different types of callback has the different priority. Here are the priorities for:

Reference documentation: https://docs.ros2.org/latest/api/rclpy/api/execution_and_callbacks.html#module-rclpy.executors

Also made some small fixes like spaces after commas and periods.

[xmfcx]

@sykwer

As a result, we’d like to keep this document blank until the functionality as explained above become fixed. Thanks!

I think it's ok to merge this proposal (after reviewing) and when you have a better proposal, it can be improved with that? Is that ok with you?

[xmfcx]

@shulanbushangshu

It's a great documentation addition overall, thanks for the work.

Before it's merged, could you also update the punctuation please? Mainly put a space after commas and periods.

[sykwer]

I agree with this opinion.

#282 (review)

It is better, I think, that this section honestly tells that task scheduling is not designed and Autoware runs on a task scheduling by combination of ROS 2 and Linux kernel.

This opinion most accurately describes reality.

[xmfcx]

@sykwer

I agree with this opinion.

What do you agree with exactly? What do you think we should do in this PR?

[shulanbushangshu]

@sykwer @xmfcx @takam5f2
Thank for your check. I will continue to pay attention to this section. As said,task scheduling is not designed in autoware and it just runs on a task scheduling by combination of ROS 2 and Linux kernel.
As in the future develop of autoware, autoware will develop user-defined and centralized task scheduler?
My understand about this section is that something about ROS2 executor in application of autoware by now.(Because task scheduling is not designed by now).
If it is necessary to explain the future ,I agree that keeping this document blank.

[xmfcx]

Created the issue to address this problem once the solution @sykwer and @takam5f2 suggested is implemented. Still, thank you @shulanbushangshu for working on this documentation!