[storage] Replace pruner worker polling with channel-based wake

[wqfish]

Replace the 1ms sleep-poll loop in PrunerWorker with a
sync_channel(1)-based blocking wait.

Before: Each pruner worker thread (state_merkle, ledger, state_kv) woke up
every 1ms to check is_pruning_pending(), causing ~1000 context switches/sec
per thread even when fully idle.

After: The worker blocks on recv() when there's no pending work, and is
woken only when:

• set_target_db_version is called with a new target (try_send(()))
• The PrunerWorker is dropped (sender dropped → recv() returns Err)

This also eliminates the PrunerWorkerInner struct — the channel naturally
separates the producer (sender on PrunerWorker) from the consumer (receiver
moved into the worker thread). Error backoff is bumped from 1ms to 100ms.

Co-Authored-By: Claude Opus 4.6 noreply@anthropic.com

---

Note

Medium Risk
Changes the pruner worker’s concurrency model from tight sleep-polling to channel-based blocking wakeups, which can affect shutdown/wakeup behavior and risk hangs if signaling is missed. Scope is limited to PrunerWorker, but it runs continuously in production so regressions would be noisy.

Overview
Replaces PrunerWorker’s 1ms sleep/poll loop with a sync_channel(1) wake mechanism so idle pruner threads block on recv() and only run when signaled.

set_target_db_version() now try_send(())s to wake the worker after advancing the target version, and Drop signals shutdown by dropping the sender (worker exits when the channel disconnects). The old PrunerWorkerInner + AtomicBool stop flag is removed, and pruning error backoff is increased to 100ms.

^{Written by Cursor Bugbot for commit e4a6b8e. This will update automatically on new commits. Configure here.}

[github-actions]

✅ Forge suite compat success on 411b9c779ae61d440e96591183edd7ea0e0bb563 ==> e4a6b8e6df9d590914111648df0694eee02c05d3

Compatibility test results for 411b9c779ae61d440e96591183edd7ea0e0bb563 ==> e4a6b8e6df9d590914111648df0694eee02c05d3 (PR)
1. Check liveness of validators at old version: 411b9c779ae61d440e96591183edd7ea0e0bb563
compatibility::simple-validator-upgrade::liveness-check : committed: 13593.21 txn/s, latency: 2551.91 ms, (p50: 2500 ms, p70: 2700, p90: 3400 ms, p99: 3900 ms), latency samples: 446260
2. Upgrading first Validator to new version: e4a6b8e6df9d590914111648df0694eee02c05d3
compatibility::simple-validator-upgrade::single-validator-upgrade : committed: 6186.91 txn/s, latency: 5489.87 ms, (p50: 6000 ms, p70: 6100, p90: 6300 ms, p99: 6400 ms), latency samples: 212920
3. Upgrading rest of first batch to new version: e4a6b8e6df9d590914111648df0694eee02c05d3
compatibility::simple-validator-upgrade::half-validator-upgrade : committed: 6059.56 txn/s, latency: 5561.51 ms, (p50: 6100 ms, p70: 6200, p90: 6400 ms, p99: 6600 ms), latency samples: 210040
4. upgrading second batch to new version: e4a6b8e6df9d590914111648df0694eee02c05d3
compatibility::simple-validator-upgrade::rest-validator-upgrade : committed: 2941.45 txn/s, submitted: 3180.68 txn/s, expired: 239.23 txn/s, latency: 3577.31 ms, (p50: 3200 ms, p70: 4500, p90: 5100 ms, p99: 8800 ms), latency samples: 240241
5. check swarm health
Compatibility test for 411b9c779ae61d440e96591183edd7ea0e0bb563 ==> e4a6b8e6df9d590914111648df0694eee02c05d3 passed
Test Ok

• Grafana dashboard
• Humio Logs
• Axiom Logs
• Validator CPU Profile
• Fullnode CPU Profile
• Test runner output
• Test run is land-blocking

[github-actions]

✅ Forge suite realistic_env_max_load success on e4a6b8e6df9d590914111648df0694eee02c05d3

two traffics test: inner traffic : committed: 16041.60 txn/s, latency: 2342.71 ms, (p50: 2300 ms, p70: 2400, p90: 2700 ms, p99: 3000 ms), latency samples: 5971320
two traffics test : committed: 100.02 txn/s, latency: 804.09 ms, (p50: 800 ms, p70: 800, p90: 900 ms, p99: 1200 ms), latency samples: 1760
Latency breakdown for phase 0: ["MempoolToBlockCreation: max: 1.791, avg: 1.686", "ConsensusProposalToOrdered: max: 0.179, avg: 0.175", "ConsensusOrderedToCommit: max: 0.123, avg: 0.102", "ConsensusProposalToCommit: max: 0.296, avg: 0.277"]
Max non-epoch-change gap was: 0 rounds at version 0 (avg 0.00) [limit 4], 0.85s no progress at version 16239 (avg 0.08s) [limit 15].
Max epoch-change gap was: 0 rounds at version 0 (avg 0.00) [limit 4], 0.29s no progress at version 2738479 (avg 0.29s) [limit 16].
Test Ok

• Grafana dashboard
• Humio Logs
• Axiom Logs
• Validator CPU Profile
• Fullnode CPU Profile
• Test runner output
• Test run is land-blocking

[github-actions]

✅ Forge suite framework_upgrade success on 411b9c779ae61d440e96591183edd7ea0e0bb563 ==> e4a6b8e6df9d590914111648df0694eee02c05d3

Compatibility test results for 411b9c779ae61d440e96591183edd7ea0e0bb563 ==> e4a6b8e6df9d590914111648df0694eee02c05d3 (PR)
Upgrade the nodes to version: e4a6b8e6df9d590914111648df0694eee02c05d3
framework_upgrade::framework-upgrade::full-framework-upgrade : committed: 2302.15 txn/s, submitted: 2307.44 txn/s, failed submission: 5.29 txn/s, expired: 5.29 txn/s, latency: 1289.41 ms, (p50: 1200 ms, p70: 1500, p90: 1800 ms, p99: 2400 ms), latency samples: 208980
framework_upgrade::framework-upgrade::full-framework-upgrade : committed: 2503.12 txn/s, submitted: 2513.65 txn/s, failed submission: 10.53 txn/s, expired: 10.53 txn/s, latency: 1141.35 ms, (p50: 1200 ms, p70: 1200, p90: 1500 ms, p99: 2100 ms), latency samples: 228161
5. check swarm health
Compatibility test for 411b9c779ae61d440e96591183edd7ea0e0bb563 ==> e4a6b8e6df9d590914111648df0694eee02c05d3 passed
Upgrade the remaining nodes to version: e4a6b8e6df9d590914111648df0694eee02c05d3
framework_upgrade::framework-upgrade::full-framework-upgrade : committed: 2546.41 txn/s, submitted: 2553.34 txn/s, failed submission: 6.93 txn/s, expired: 6.93 txn/s, latency: 1167.66 ms, (p50: 1200 ms, p70: 1200, p90: 1500 ms, p99: 2100 ms), latency samples: 227741
Test Ok

• Grafana dashboard
• Humio Logs
• Axiom Logs
• Validator CPU Profile
• Fullnode CPU Profile
• Test runner output
• Test run is land-blocking