[Doc] Add scheduler cache and snapshot design #4856
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Summary of ChangesHello @handan-yxh, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed! This pull request introduces comprehensive documentation for the Agent scheduler's cache and snapshot design. The update details significant optimizations aimed at enhancing scheduling throughput and concurrency, including advanced data structures and mechanisms for efficient, incremental updates and parallel processing across multiple workers. Highlights
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Code Review
This pull request adds valuable documentation for the scheduler cache and snapshot design, replacing the 'TBD' section with a clear and detailed explanation of the optimizations. The new content is well-structured and informative. My review includes a couple of minor formatting suggestions to improve readability.
docs/design/agent-scheduler.md
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| Design of snapshot fast update mechanism and why. | ||
| TBD | ||
| To improve the overall scheduling throughput of the Agent scheduler, we optimized the Cache and Snapshot data structures and algorithms. | ||
| 1. **Generation-based Incremental Updates**: Each node in the cache maintains a monotonically increasing generation number. When a node's state changes (pod addition/removal, resource updates), its generation is incremented and the node is moved to the head of a doubly linked list. During snapshot updates, only nodes with generation numbers greater than the snapshot's current generation are processed.Significantly reduces the number of nodes that need to be processed for each update. |
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There appears to be a missing space after the period, which affects readability. Please add a space between the sentences.
| 1. **Generation-based Incremental Updates**: Each node in the cache maintains a monotonically increasing generation number. When a node's state changes (pod addition/removal, resource updates), its generation is incremented and the node is moved to the head of a doubly linked list. During snapshot updates, only nodes with generation numbers greater than the snapshot's current generation are processed.Significantly reduces the number of nodes that need to be processed for each update. | |
| 1. **Generation-based Incremental Updates**: Each node in the cache maintains a monotonically increasing generation number. When a node's state changes (pod addition/removal, resource updates), its generation is incremented and the node is moved to the head of a doubly linked list. During snapshot updates, only nodes with generation numbers greater than the snapshot's current generation are processed. Significantly reduces the number of nodes that need to be processed for each update. |
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Okay, I'll fix it.
docs/design/agent-scheduler.md
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| - Doubly Linked List: Maintains nodes in recency order (most recently updated at head). | ||
| - Hash Map: Provides O(1) node lookup by name. | ||
| - Indexed Snapshot: Snapshot maintains maps for quick node position lookup. | ||
| 3. **Concurrent Access Support**: The read-write lock separation design supports multiple workers concurrently accessing and updating their individual snapshots. Each worker maintains an independent snapshot instance, avoiding contention during scheduling cycles.Significantly improves concurrency performance in multithreaded scenarios. |
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There appears to be a missing space after the period, which affects readability. Please add a space between the sentences.
| 3. **Concurrent Access Support**: The read-write lock separation design supports multiple workers concurrently accessing and updating their individual snapshots. Each worker maintains an independent snapshot instance, avoiding contention during scheduling cycles.Significantly improves concurrency performance in multithreaded scenarios. | |
| 3. **Concurrent Access Support**: The read-write lock separation design supports multiple workers concurrently accessing and updating their individual snapshots. Each worker maintains an independent snapshot instance, avoiding contention during scheduling cycles. Significantly improves concurrency performance in multithreaded scenarios. |
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Okay, I'll fix it.
docs/design/agent-scheduler.md
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| ## Snapshot maintenance | ||
| Design of snapshot fast update mechanism and why. | ||
| TBD | ||
| To improve the overall scheduling throughput of the Agent scheduler, we optimized the Cache and Snapshot data structures and algorithms. |
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add some background about the purpose of snapshot and relationships between snapshot and nodes in cache
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Some background information has been added.
docs/design/agent-scheduler.md
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| ## Snapshot maintenance | ||
| Design of snapshot fast update mechanism and why. | ||
| TBD | ||
| To improve the overall scheduling throughput of the Agent scheduler, we optimized the Cache and Snapshot data structures and algorithms. |
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Prefer more information about how the snapshot lifecycle is managed, such as when snapshots are created, updated and deleted, etc.
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Some text has been added, and simple diagrams will be used to describe the lifecycle more clearly.
docs/design/agent-scheduler.md
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| Design of snapshot fast update mechanism and why. | ||
| TBD | ||
| To improve the overall scheduling throughput of the Agent scheduler, we optimized the Cache and Snapshot data structures and algorithms. | ||
| 1. **Generation-based Incremental Updates**: Each node in the cache maintains a monotonically increasing generation number. When a node's state changes (pod addition/removal, resource updates), its generation is incremented and the node is moved to the head of a doubly linked list. During snapshot updates, only nodes with generation numbers greater than the snapshot's current generation are processed.Significantly reduces the number of nodes that need to be processed for each update. |
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For the processing logic of the incremental update here, it would be better to have a simple schematic diagram.
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Alright, I will add a diagram.
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Signed-off-by: handan-yxh <[email protected]>
Signed-off-by: handan-yxh <[email protected]>
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6 participants
What type of PR is this?
doc
What this PR does / why we need it:
Add scheduler cache and snapshot design
Proposal details: https://docs.google.com/document/d/1NDTEGulhQ__sdZ_c2kN3ojtJIZie5O7_GyZyKIOLz-g/edit?tab=t.3q3qlfh4r4sf#heading=h.9r4wotc3nl4d
Which issue(s) this PR fixes:
Fixes #4722
Special notes for your reviewer:
Does this PR introduce a user-facing change?
NONE