7.2.1. Overview

While PRRTE does not itself contain a scheduler, it does support scheduler-related operations as a means of providing users and researchers with an environment within which they can investigate/explore dynamic operations. It will , of course, interact with any PMIx-based scheduler to support allocation requests and directives for executing jobs within an allocation.

In addition, however, PRRTE provides a pseudo-scheduler for research purposes. The psched daemon is not a full scheduler - i.e., it does not provide even remotely optimal resource assignments, nor is it in any way production qualified. For example, the psched algorithms are not particularly fast and are focused more on providing functionality than supporting large volumes of requests.

Within that context, psched will:

• assemble a resource pool based on the usual PRRTE resource discovery methods. This includes reading the allocation made by a host environment, or provided by hostfile and/or dash-host command line options.

• upon receipt of allocation requests (either directly from tools or relayed by PRRTE), check to see if the specified resources are available.