Resource: LCU13 Name: Tracking and Debugging for Networking Applications Date: 29-10-2013 Speaker: Magnus Karlsson Video: http://www.youtube.com/watch?v=z3BdRxMNuwA

1. Tracing & Debugging for
Networking Applications
Magnus Karlsson, LSI

2. connect.linaro.org
• Networking is the application
• The networking app runs in user mode
• Special HW with highly integrated networking functions
• Lots of accelerators
Application Domain
Networking
Apps
Linux
Control
Apps
Net stack
CPU
0 CPU
1
–
CPU
N
Networking Accelerators & HW
Networking
SoC
User space
Kernel space

3. connect.linaro.org
• Functionality for debugging and performance tuning of networking
applications
• Reachable from user space
• Performance data and traces even from processing that does not
touch cores. HW/SW implementation agnostic API
• Plug in architecture needed as each vendor’s HW is different
• Standard Linux interfaces
o CoreSight access library
• High resolution timers
What is missing?
Requirements

4. connect.linaro.org
• Ftrace
• LTTng
• Perf
• ftrace
• Uprobes
• Systemtap
• Ktap?
• GDB
• Cat /proc/*
• Etc…
What to build on?
Existing Linux Features

5. connect.linaro.org
• Access to CoreSight (access lib from ARM)
• Device driver for SW annotations to STM
• LTTng & ftrace writing to trace buffers (ETB) instead of file
• Decoding of ETB data through Linux (not DS-5). Open decoder needed
• GDB access to HW trace functionality
• Plugin of vendor’s accelerators into ftrace / LTTng
• Monitoring core isolation disturbances
• What about scalability?
• Feature uplift to x86 level? What functionality to target?
• What does ODP need?
What more to add?
What Functionality to Add?

6. connect.linaro.org
• For many people looking at this, English may be their second,
third or fourth language,…
• Try and keep bullet points to a minimum
• Relevant images are great
• Contact marketing (Steve and Jen) if you need some help with
images and/or editing
Slide 1

7. More about Linaro: http://www.linaro.org/about/
More about Linaro engineering: http://www.linaro.org/engineering/
How to join: http://www.linaro.org/about/how-to-join
Linaro members: www.linaro.org/members
connect.linaro.org