MigThread: Thread migration in DSM systems

Distributed Shared Memory (DSM) systems provide a logically shared memory over physically distributed mem-ory to enable parallel computation on Networks of Work-stations (NOWs). In this paper, we propose an infrastruc-ture for DSM systems to utilize idle cycles in the network by thread migration. To maintain high portability and flexibility, a generic thread migration package, MigThread, is implemented at language level. At compile-time, a preprocessor scans C programs to build thread state, detects possible thread adaptation points, and transforms the source code accord-ingly. At runtime, MigThread moves DSM threads around to utilize idle cycles on remote machines. Since the physical thread state is transformed into a logical form, MigThread is ready to be used in heterogeneous DSM systems. We im-plemented MigThread in a DSM system Strings. A compar-ison with other migration schemes and some performance measurements on real applications are reported to show the efficiency. Key Words: Software Distributed Shared Memory, adaptive parallel computing, thread migration, thread scheduling, compile-time code transformations.