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