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Browse Prior Art Database

Parallel Aware Task Dispatcher

IP.com Disclosure Number: IPCOM000030929D
Original Publication Date: 2004-Sep-01
Included in the Prior Art Database: 2004-Sep-01
Document File: 1 page(s) / 44K

Publishing Venue

IBM

Abstract

This invention provides coordinated scheduling of tasks in a parallel job, where the coordination is across both the tasks on a single compute node and across multiple compute nodes.

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This is the abbreviated version, containing approximately 57% of the total text.

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Parallel Aware Task Dispatcher

Disclosed is a system that provides coordinated scheduling of tasks in a parallel job, typically a job using message passing and running under the Parallel Environment for AIX. The parallel aware dispatcher consists of two components: 1) modifications to the AIX dispatcher and 2) a global co-scheduler, which uses a globally synchronized clock to make scheduling decisions. The functions performed by each are outlined below, and discussed in more detail in the paper "Improving the Scalability of Parallel Jobs by adding Parallel Awareness to the Operating System", which appeared in the Proceedings of the ACM/IEEE SC2003 Conference, Phoenix, Arizona, November 15-21, 2003 [*].

Co-scheduler functions:

    Root-level process running on each AIX compute node, periodically reading a globally synchronized clock (such as provided by the IBM Cluster 1600 SP Switch2 or pSeries High Performance Switch).

    Process uses the clock to precisely determine "compute time slots" and "daemon time slots" which are the same on each node of the system, and changes the AIX dispatching priority of the tasks under its control at the beginning and end of these time slots.

    The tasks of a parallel job register with the co-scheduler when they begin running, thus enabling the co-scheduler to identify which tasks are to be controlled.

    Process sets the AIX clock on each node to be synchronized with the global switch clock, accounting for the time that is incurred in such se...