[Colloq] Comprehensive Exam by Xin Dong, Monday, March 14

[Rachel Kalweit]

The College of Computer and Information Science Presents:

A Comprehensive Exam
Speaker: Xin Dong
Advisor:  Gene Cooperman

Date: Monday, March 14, 2011
Time: 10:30AM
Place: WVH 366


Title:  Source-Level Transformation of Legacy Sequential Program into Scalable Multi-Threaded Code

Abstract:

This proposal will focus on code transformation for legacy sequential programs toward thread-level parallelism on many-core computers.  It highlights a semi-automatic method: Scalable Task-Oriented Code Transformation (STOCT).  STOCT introduces thread parallelism for sequential code via a series of code transformation steps.  STOCT’s goal is: Given a large C/C++ software program, transform the source code to replace several independent copies of a sequential process with an equivalent single process consisting of several threads.  This takes advantage of many-core computers in a memory-efficient and scalable manner.

The STOCT methodology is implemented in the parallelization work for three widely varying applications:  (i) a simulation toolkit Geant4; (ii) a linear system solver based on ILU(k) preconditioning; and (iii) a large-scale data analysis tool AliRoot. STOCT bridges the gap from sequential programming to concurrent programming by decomposing the parallelization into four subgoals:  to exert more parallelism, to share more data, to guarantee correctness, and to achieve scalability.

STOCT has the following features:  (i) to pursue thread safety by maximal parallelism in which only the minimal shared data set is allowed; (ii) to reduce memory footprint by sharing some user-level data whose value is no longer changed after initialization; (iii) to guarantee runtime correctness, which is weaker and yet strong enough for production; and (iv) to achieve scalability by eliminating two serious performance bottlenecks particular for shared-memory computation: memory allocation and cache coherence miss.