OpenResty XRay Jan 27, 2025

OpenResty XRay Updated Jan 27, 2025 7 mins read

Use C++ to Dynamic-Trace C++ Applications

• Setting Up the Target C++ Program
• Crafting the C++ (or Y++) Analyzer
• Operationalizing the Target and Analyzer
• Advancing Support for Complex C++ Applications
• About the Debug Symbols

OpenResty XRay Mar 14, 2024

OpenResty XRay Updated Mar 14, 2024 7 mins read

Automatic Core Dump Analysis (using OpenResty XRay)

• Check the core dump file
• Use the guided analysis feature of OpenResty XRay to analyze the core file
• Automatic analysis and reports
• What is OpenResty XRay

OpenResty XRay Aug 15, 2023

OpenResty XRay Updated Aug 15, 2023 5 mins read

Two bugs in Linux kernels' tracing subsystem (found by OpenResty XRay)

• Kernel deadlocks in user-space memory reading
• Data races in x86 breakpoint insertion of the kernel
• What is OpenResty XRay

OpenResty XRay Apr 10, 2024

OpenResty XRay Updated Apr 10, 2024 26 mins read

The Wonderland of Dynamic Tracing (Part 1 of 3)

• Dynamic Tracing
• What It Is
• Too Good to be True?
• How it Works
• Still Having Doubts?
• The Advantages of Dynamic Tracing
• DTrace
• SystemTap
• DTrace and SystemTap
• Applications of SystemTap in Production

OpenResty XRay Apr 10, 2024

OpenResty XRay Updated Apr 10, 2024 15 mins read

The Wonderland of Dynamic Tracing (Part 2 of 3)

• Flame Graphs
• Methodology
• Knowledge Is Power
• Open-Source and Debug Symbols

OpenResty XRay Apr 10, 2024

OpenResty XRay Updated Apr 10, 2024 7 mins read

The Wonderland of Dynamic Tracing (Part 3 of 3)

• Dynamic Tracing Support in Linux Kernels
• Hardware Tracing
• Analyze Remains of Dead Process
• Traditional Debugging Technologies
• A Messy World of Debugging
• OpenResty XRay

OpenResty XRay Apr 10, 2024

OpenResty XRay Updated Apr 10, 2024 6 mins read

Resolving Bilibili’s major site incident with OpenResty XRay

• The incident
• Process of resolution
• Hardening after the incident
• OpenResty XRay Services

OpenResty XRay Jun 28, 2023

OpenResty XRay Updated Jun 28, 2023 11 mins read

Tracing the Slowest PCRE Regular Expressions in OpenResty or Nginx Processes

• System Environment
• Narrowing Down the Culprit without Guessing
• Limiting the execution overhead of PCRE
• Non-Backtracking Regular Expression Engines
• Lua’s Builtin Patterns
• Tracing Applications inside Containers
• How The Tools are Implemented
• The Overhead of the Tools

OpenResty XRay Apr 10, 2024

OpenResty XRay Updated Apr 10, 2024 9 mins read

Listing Loaded Lua Modules in OpenResty or Nginx Processes

• System Environment
• Names of Loaded Lua Modules
• Running Directly in the Web Console
• Tracing Applications inside Containers
• How The Tools are Implemented
• The Overhead of the Tools

OpenResty XRay Sep 20, 2023

OpenResty XRay Updated Sep 20, 2023 14 mins read

Ylang: Universal Language for eBPF, Stap+, GDB, and More (Part 4 of 4)

• Transparent Container Tracing
• Efficient Stack Unwinding
• Analyzing Dead Processes (Core Dumps)
• Very Low Tracing Overhead
• Standard Ylang Libraries & Tools
• Network Filtering & Control
• The Ylang Compiler’s Implementation
• Operating System Support
• Contributions to Open-Source Communities

OpenResty XRay Jul 10, 2023

OpenResty XRay Updated Jul 10, 2023 10 mins read

Ylang: Universal Language for eBPF, Stap+, GDB, and More (Part 3 of 4)

• The Language Syntax (Continued)
  • String Literals
  • Built-in Regex Support
  • Full Control-Flow Support
  • Floating-Point Number Support
  • Compared to Open-Source Toolchains
• Transparent Debug Symbol Handling
  • Debug Symbols: No Runtime Overhead
  • Centralized Package Database
  • Fuzzy Matching Debug Symbols

OpenResty XRay Aug 21, 2023

OpenResty XRay Updated Aug 21, 2023 14 mins read

Ylang: Universal Language for eBPF, Stap+, GDB, and More (Part 2 of 4)

• The Language Syntax (Continued)
  • Macros with Extensions
  • Tracer and Tracee Spaces
  • Probes
  • Extended Variable Types

OpenResty XRay Jul 10, 2023

OpenResty XRay Updated Jul 10, 2023 14 mins read

Ylang: Universal Language for eBPF, Stap+, GDB, and More (Part 1 of 4)

• What is Dynamic Tracing
• Why the “Y” Name
• Getting Started
• Various Backends and Runtimes
• Why a Unified Frontend Language
• The Language Syntax

OpenResty XRay Apr 10, 2024

OpenResty XRay Updated Apr 10, 2024 19 mins read

Introduction to Lua-Land CPU Flame Graphs

• What is a Flame Graph
• Simple Lua samples
• Complicated Lua applications
• Sampling overhead
• Safety
• Compatibility
• Other types of Lua-land Flame Graphs

OpenResty XRay Jul 6, 2023

OpenResty XRay Updated Jul 6, 2023 10 mins read

Memory Fragmentation in OpenResty and Nginx's Shared Memory Zones

• An empty zone
• Filling entries of similar sizes
• Deleting odd-numbered keys
• Deleting the keys in the first half
• Mitigating Fragmentation

OpenResty XRay Jul 6, 2023

OpenResty XRay Updated Jul 6, 2023 13 mins read

How OpenResty and Nginx Shared Memory Zones Consume RAM

• Slabs and pages
• What is allocated is not what is paid for
• Fake Memory Leaks
• HUP reload

OpenResty XRay Apr 10, 2024

OpenResty XRay Updated Apr 10, 2024 11 mins read

How OpenResty and Nginx Allocate and Manage Memory

• On The System Level
• On The Application Level
• For Traditional Nginx Servers