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.

Phase-based Tuning for Better Utilization of Performance-Asymmetric Multicore Processors

Tyler Sondag and Hridesh Rajan


The latest trend towards performance asymmetry among cores on a single chip of a multicore processor is posing new challenges. For effective utilization of these performance-asymmetric multicore processors, code sections of a program must be assigned to cores such that the resource needs of code sections closely matches resource availability at the assigned core. Determining this assignment manually is tedious, error prone, and significantly complicates software development. To solve this problem, we contribute a transparent and fully-automatic process that we call phase-based tuning which adapts an application to effectively utilize performance-asymmetric multicores. Compared to the stock Linux scheduler we see a 36% average process speedup, while maintaining fairness and with negligible overheads.

Bibliographic Information

author = {Tyler Sondag and Hridesh Rajan},
title = {Phase-based Tuning for Better Utilization of Performance-Asymmetric Multicore Processors},
booktitle = {International Symposium on Code Generation and Optimization (CGO)},
location = {Chamonix, France},
month = {April},
year = {2011},

Most recent paper version: PDF

Presentation: PDF

Previous version appeared as Technical Report 08-14a, Computer Science, Iowa State University, March, 2010. [PDF]