bitvid/docs/perf-reports/weekly-perf-report-2026-02-13.md

Weekly Performance Report — 2026-02-13

Agent: bitvid-perf-deepdive-agent Focus: Relay Request Concurrency

Executive Summary

Identified a critical performance risk in js/nostr/reactionEvents.js where reaction list and publish operations were using unbounded Promise.all across all configured relays. This could lead to network saturation, browser connection limits (blocking other requests), and potential timeouts for users with many relays.

Optimization: Replaced Promise.all with pMap to enforce a concurrency limit of 3 (RELAY_BACKGROUND_CONCURRENCY), aligning with best practices established in commentEvents.js.

Methodology

Scenario

Simulate listVideoReactions call with a client configured for 20 relays.

• Tools: benchmarks/reaction_loading_bench.mjs (new harness)
• Environment: Node.js 22 (Agent Environment)
• Metric: Peak concurrent pool.list() calls.

Baseline Measurements

Metric	Value	Notes
Peak Concurrency	20	Unbounded; fired all requests simultaneously.
Total Time (Mock)	~111ms	Limited only by the longest single request (mock delay 100ms).

After Optimization

Metric	Value	Notes
Peak Concurrency	3	Capped by RELAY_BACKGROUND_CONCURRENCY.
Total Time (Mock)	~705ms	Increased latency is expected and acceptable for background operations to preserve network health.

Changes

1. Concurrency Limiting in js/nostr/reactionEvents.js

• Before: await Promise.all(relayList.map(...))
• After: await pMap(relayList, ..., { concurrency: 3 })
• Impact: Prevents "thundering herd" of WebSocket requests.

2. New Benchmark Harness

• Added benchmarks/reaction_loading_bench.mjs to reproducible measure concurrency of reaction loading.

Verification

• Unit tests (tests/nostr/reaction-events.test.mjs) passed.
• Benchmark confirmed concurrency cap is active.

Next Steps

• Audit js/nostr/viewEvents.js: Similar unbounded Promise.all pattern exists there and should be patched in a future run.
• Audit js/nostr/dmSignalEvents.js: Another potential candidate for concurrency limiting.