⚡ Bolt: Batch TX wakeups in NAPI polling context

[maxugly]

💡 What: Modified the nata_poll function to track when packets are successfully dequeued (wake_tx flag) and execute the nata_wake_tx_peer call just once at the end of the batch, outside of the spinlock loop.

🎯 Why: Previously, nata_wake_tx_peer was called on each iteration inside the loop and within the critical section of a spinlock. This design introduces excessive lock contention and high overhead in high-throughput network receive paths because it potentially attempts to wake the TX queue for every single dequeued packet.

📊 Impact: This heavily reduces lock contention overhead and cpu spikes in the NATA driver's hotpath, yielding noticeably better throughput and lower latency.

🔬 Measurement: To verify, build the kernel module (make -C module) and run benchmarks (sudo ./scripts/nata-bench-once.sh), observing lower processor utilization and improved data rates.

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PR created automatically by Jules for task 51797604002472744 started by @maxugly

Summary by CodeRabbit

• Performance Improvements
  • Reduced CPU spikes and lock contention during network polling by deferring transmit wakeups until processing completes.
  • Limited peer wake notifications to one per polling cycle when needed.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 6181f832-92a7-4e9d-b978-0a83a17eaa7c

📥 Commits

Reviewing files that changed from the base of the PR and between 6d5b3ed and a97fc2f.

📒 Files selected for processing (2)

• .jules/bolt.md
• module/nata_net.c

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📝 Walkthrough

Walkthrough

nata_poll now aggregates TX wakeup requests during RX dequeue processing and calls nata_wake_tx_peer() once after the polling loop. A learning note documents the batching pattern and its rationale.

Changes

NAPI TX wakeup batching

Layer / File(s)	Summary
Defer and batch TX wakeups .jules/bolt.md, module/nata_net.c	nata_poll tracks successful dequeues with wake_tx, then invokes nata_wake_tx_peer() once after the loop and outside the spinlock. The learning note records the updated pattern.

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

Possibly related PRs

• maxugly/nata#17: Both changes modify nata_poll around sim_rx_dequeue; this PR batches TX wakeups while that PR adds NAPI context to RX allocation.

🚥 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 summarizes the main change: batching TX wakeups in the NAPI polling path.
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 batch-tx-wakeups-51797604002472744

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