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Dispatching Virtual Machine Servers As Control Program Tasks

IP.com Disclosure Number: IPCOM000035653D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Shultz, SS: AUTHOR

Abstract

Because of the complexity and high cost of putting support into the Control Program (CP) portion of the Virtual Machine/System Product (VM/SP) as opposed to the cost of developing code of virtual machines, virtual machine servers have been developed to perform functions which are naturally in the domain of CP. While the development cost for these functions is greatly improved this way, the resulting servers cause a greater performance degradation to the system as a whole than does the analogous function provided in CP. Disclosed is a method to keep the benefits of developing servers, while gaining some if not all of the performance of a CP function. This is done by dispatching server virtual machines as if they were CP tasks, thus approximating the performance of a system where these functions are included in CP.

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Dispatching Virtual Machine Servers As Control Program Tasks

Because of the complexity and high cost of putting support into the Control Program (CP) portion of the Virtual Machine/System Product (VM/SP) as opposed to the cost of developing code of virtual machines, virtual machine servers have been developed to perform functions which are naturally in the domain of CP. While the development cost for these functions is greatly improved this way, the resulting servers cause a greater performance degradation to the system as a whole than does the analogous function provided in CP. Disclosed is a method to keep the benefits of developing servers, while gaining some if not all of the performance of a CP function. This is done by dispatching server virtual machines as if they were CP tasks, thus approximating the performance of a system where these functions are included in CP.

When a server virtual machine logs on, CP identifies through the directory that this is a server virtual machine and dispatches this virtual machine in a manner more consistent with CP functions. The server is always dispatched ahead of non-servers and is never made non-dispatchable. Additionally, and most importantly, this machine never competes for a spot on the dispatchable queue with other virtual machines. That is, no virtual machines are prevented from being made dispatchable as a result of one or more servers always being on the dispatchable queue. This is key to the performance of the s...