Sapha: Static Approximate Phase Analysis.

These pages describe work carried out on design implementation, and applications of a technique that we call static approximate phase analysis. The PI is Hridesh Rajan and much of the work is carried out by Tyler Sondag.


March 2011: Invited talk on phase-based tuning at SMART '11.

December 2010: Paper on Frances-A tool accepted for CCSC 2011.

November 2010: Paper on phase-guided tuning accepted for CGO 2011.

August 2010: Paper on cache analysis accepted for RTSS 2010.

January 2010: Tutorial on Frances tool accepted for CCSC 2010.

October 2009: Paper on Frances tool accepted for SIGCSE 2010.

A More Precise Abstract Domain For Multi-level Caches for Tighter WCET Analysis

Tyler Sondag and Hridesh Rajan


Many program analyses and optimizations rely on knowledge of cache behavior. The precision of the underlying cache model is increasingly important with the recent uptake of multi-core and many-core architectures for two reasons. First, per-core cache sizes generally decrease as the number of cores becomes large resulting in more cache misses. Second, large scale sharing of the communication bandwidth to memory increases contention resulting in greater cost of cache misses. We present a sound technique for cache behavior analysis that handles instruction and data caches as well as a variety of multi-level cache policies. The resulting analysis is applicable to current general-purpose processors. Our technique relies on a new abstraction, live caches which model relationships between cache levels to improve accuracy of multi-level cache analysis. In an existing many-core cache configuration, live caches improve L2 hit accuracy by an average of 5.7%. Among others, this reduces the upper bound on memory accesses for worst case execution time (WCET) by an average 6.4%.

Bibliographic Information

author = {Tyler Sondag and Hridesh Rajan},
title = {A More Precise Abstract Domain For Multi-level Caches for Tighter {WCET} Analysis},
booktitle = {RTSS '10: The 31st IEEE Real Time Systems Symposium},
location = {San Diego, CA},
month = {November},
year = {2010},

Most recent paper version: PDF

Presentation: PDF

Previous version appeared as Technical Report 09-20b, Computer Science, Iowa State University, April 1, 2010. [PDF]