LIS is More: Improved Diagnostic Logging in Sensor Networks
with Log Instrumentation Specifications
Roy Shea @ UCLA
What is LIS
• A logging framework that respects the bandwidth limitations of the distributed embedded domain
Savings From Bit Aligned Logging
Standard Identifier Assignment
Real Programs Have Rich Structure
Local Token Scoping for Short Identifiers
Architecture of LIS
header read_done globalcontrolflow read_done local if send_busyfooter read_done point
Example
Example
Example
Example
Example
Number of Tokens Affects Bandwidth
Limitations
• Current LIS implementation bases scopes on function boundaries
• Not compress program data
• Care must be taken to guarantee parsable logs– Parsing depends on knowing the local context
Conclusions
• Established technique of bit aligning data used to reduce log bandwidth
• Local token scoping can produce consistently small token identifier encodings
• LIS automates the difficulties of token scoping and provides a general interface for describing logging tasks
Discussion