Priyanka Tembey

A case for coordinated resource management in heterogeneous multicore platforms

Recent advances in multi- and many-core architectures include increased hardware-level parallelism (i.e., core counts) and the emergence of platform-level heterogeneity. System software managing these platforms is typically comprised of multiple independent resource managers (e.g., drivers and specialized runtimes) customized for heterogeneous vs. general purpose platform elements. This independence, however, can cause performance degradation for an application that spans diverse cores and resource managers, unless managers coordinate with each other to better service application needs. This paper first presents examples that demonstrate the need for coordination among multiple resource managers on heterogeneous multicore platforms. It then presents useful coordination schemes for a platform coupling an IXP network processor with x86 cores and running web and multimedia applications. Experimental evidence of performance gains achieved through coordinated management motivates a case for standard coordination mechanisms and interfaces for future heterogeneous many-core systems.

SMT Switch: Software Mechanisms for Power Shifting

Simultaneous multithreading (SMT) as a processor design to achieve higher levels of system and application throughput is a well-accepted and deployed technique in most desktop and server processors. We study the power implications of varying SMT levels i.e., thread counts per core for various multi-threaded applications on a real SMT multicore platform, and introduce a novel software mechanism of changing SMT level of a core to tune platform power. Power-shifting policies by varying per core SMT levels for performance benefits within a power cap are introduced. Projected power savings (of 15%) for a streaming parallel benchmark can be attained using SMT-level power shifting mechanisms.