Development of a dynamic time sharing scheduled environment. Final report

Technical Report · Wed Oct 01 04:00:00 EDT 1997

DOI:https://doi.org/10.2172/656743· OSTI ID:656743

Massively parallel computers, such as the Cray T3D, have historically supported resource sharing solely with space sharing. In that method, multiple problems are solved by executing them on distinct processors. This project developed a dynamic time- and space-sharing scheduler to achieve greater interactivity and throughput than could be achieved with space-sharing alone. CRI and LLNL worked together on the design, testing, and review aspects of this project. There were separate software deliverables. CRI implemented a general purpose scheduling system as per the design specifications. LLNL ported the local gang scheduler software to the LLNL Cray T3D. In this approach, processes are allocated simultaneously to all components of a parallel program (in a gang). Program execution is preempted as needed to provide for interactivity. Programs are also relocated to different processors as needed to efficiently pack the computer`s torus of processors. In phase one, CRI developed an interface specification after discussions with LLNL for system-level software supporting a time- and space-sharing environment on the LLNL T3D. The two parties also discussed interface specifications for external control tools (such as scheduling policy tools, system administration tools) and applications programs. CRI assumed responsibility for the writing and implementation of all the necessary system software in this phase. In phase two, CRI implemented job-rolling on the Cray T3D, a mechanism for preempting a program, saving its state to disk, and later restoring its state to memory for continued execution. LLNL ported its gang scheduler to the LLNL T3D utilizing the CRI interface implemented in phases one and two. During phase three, the functionality and effectiveness of the LLNL gang scheduler was assessed to provide input to CRI time- and space-sharing efforts. CRI will utilize this information in the development of general schedulers suitable for other sites and future architectures. All phases of this project were completed on time and all deliverables were met without significant changes to the original statement of work.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 656743
• Report Number(s): LLNL--98006076; ON: DE98006076; BR: DP0301; CRN: TC-824-94E
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
CRAY COMPUTERS
PARALLEL PROCESSING
PERFORMANCE
PROGRESS REPORT
SUPERCOMPUTERS
TASK SCHEDULING