Analyzer ngx-req-lj-yield-latency

# Name

ngx-req-lj-yield-latency - Nginx Request LuaJIT Yield Latency Flame Graph

This analyzer profiles the latency of LuaJIT yield operations during Nginx request processing in applications such as OpenResty and Kong. It captures stack traces when Lua coroutines yield control back to the Nginx event loop, measuring the time spent in each yield operation. The analyzer generates flame graphs that visualize yield latency distribution across Lua-level function calls, helping identify performance bottlenecks caused by blocking operations or inefficient coroutine usage in request handling.

# Resource Category

Latency.

# Application Type & Technical Stack

• OpenResty
• Kong
• APISIX

# Command Line Syntax

The analyzer can be invoked directly on the command-line via the orxray utility from the openresty-xray-cli software package.

Alternatively, the analyzer can also be invoked manually or automatically on the web console UI of OpenResty XRay (like on the Advanced web page).

# PID is the target process PID.
orxray analyzer run ngx-req-lj-yield-latency -p PID

# trace a shell command directly
orxray analyzer run ngx-req-lj-yield-latency -c SHELL_CMD

# PGID is the process group ID or any process's PID within the target process
# group.
orxray analyzer run ngx-req-lj-yield-latency -p -PGID

# trace any processes started from the specified executable path.
orxray analyzer run ngx-req-lj-yield-latency --exe /path/to/exe/file

# Tracing Multiple Processes

Supported.

# Output Formats

• Flame Graphs

# Author

The OpenResty Inc. Team.

# Copyright

Copyright (C) by OpenResty Inc. All rights reserved.