openclaw - 💡(How to fix) Fix Event loop blocking causing 40+ second delays after upgrading to 2026.5.x

Problem Description

After upgrading from 2026.4.x to 2026.5.x, experiencing severe event loop blocking causing 40+ second delays before messages are processed.

Environment

• OpenClaw version: 2026.5.19
• Platform: Windows (Node.js 26.1.0)
• CPU: 4 cores / 8 logical processors
• RAM: 16GB

Symptoms

1. Messages to agents (keluoze, ramu, main) experience 40-60 second delays before processing starts
2. Event loop diagnostics show:
   • eventLoopUtilization: 0.957 (95.7% saturated)
   • eventLoopDelayMaxMs: 44057 (up to 44 seconds blocking)
3. Once processing starts, streaming response is fast
4. The delay is specifically in the "attempt-dispatch" phase before model inference

Expected Behavior (2026.4.x)

With 2026.4.x versions, agents responded within 10-15 seconds total. No event loop blocking issues observed.

Investigation Notes

• The issue appears after upgrading from 2026.4.x to 2026.5.x
• Node.js single-threaded architecture hasn't changed
• The problem seems related to the gateway startup overlap optimization introduced in 2026.5.18
• Key change: Gateway: overlap startup logging and plugin-service startup with channel sidecars

Startup Stages Comparison

Before (2026.4.x behavior - fast):

• attempt-workspace: ~1-2 seconds
• Total startup: ~10 seconds

After (2026.5.x - slow):

• attempt-workspace: 20+ seconds
• Total startup: 25-30 seconds
• Event loop blocked for up to 44 seconds

Question

Is this a known performance regression in 2026.5.x? Are there workarounds or config adjustments to mitigate the event loop blocking?

Thank you for investigating.