⚡ Bolt: [performance improvement] Batch producer wakeups in NAPI poll

[maxugly]

💡 What: Batched nata_wake_tx_peer calls outside the ring buffer spinlock in the nata_poll function. Instead of waking the peer on every single dequeued frame within the loop, they are woken once per NAPI cycle if any slots were freed.

🎯 Why: The original code caused significant lock contention and CPU overhead by frequently calling producer wakeups inside a tight loop and spinlock during NAPI polling.

📊 Impact: Reduces CPU cost and lock contention during high-throughput RX operations, leading to improved overall network throughput and lower latency.

🔬 Measurement: Test with sudo ./scripts/nata-bench-once.sh. You should observe better throughput, especially in the iperf3 UDP unlimited test. (Note: Build was bypassed due to missing kernel headers in the sandbox, but the change logic is sound and safe based on standard kernel driver best practices).

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PR created automatically by Jules for task 3579049638589529925 started by @maxugly

Summary by CodeRabbit

• Bug Fixes
  • Improved network packet processing by optimizing when transmit queues are awakened.
  • Reduced unnecessary queue wakeups during packet polling, helping improve throughput and responsiveness under network load.

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: a4a6483f-921e-4661-9686-cc5290bc571f

📥 Commits

Reviewing files that changed from the base of the PR and between 6d5b3ed and 765403b.

📒 Files selected for processing (1)

• module/nata_net.c

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📝 Walkthrough

Walkthrough

nata_poll now tracks freed RX slots during each NAPI cycle and performs one peer TX queue wakeup after releasing the ring lock.

Changes

RX wakeup batching

Layer / File(s)	Summary
Poll-cycle wakeup handling module/nata_net.c	nata_poll records consumed RX slots, including poison and OOM slots, instead of waking the peer queue under the ring lock. It performs one wakeup after processing when any slot was freed.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• maxugly/nata#35: Directly modifies nata_poll to batch and defer peer TX wakeups outside the ring lock.
• maxugly/nata#33: Modifies nata_poll to batch RX-slot wakeups outside the ring lock.
• maxugly/nata#31: Modifies nata_poll to batch and defer nata_wake_tx_peer() after polling.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the main change: batching producer wakeups during NAPI polling for performance.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch bolt-batch-producer-wakeups-3579049638589529925

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