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Method to manage power in a multinode scalable server using voting box in master system managment controller

IP.com Disclosure Number: IPCOM000187544D
Original Publication Date: 2009-Sep-10
Included in the Prior Art Database: 2009-Sep-10
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Abstract

This article describes a method to manage power in a scalable multinode system where platform is driving power changes but the Operating System is kept in synch. Managing power across mutiple servers cabled up to form a single system has it's challenges and this article describes one of the ways to solve that problem.

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Method to manage power in a multinode scalable server using voting box in master system managment controller

Master BMC
a. Collects info from all nodes
b. Coalesce's Interrupts into the master BMC(Base Board Management Controller)

- OS's that use ACPI( Advanced Configuration and Power Interface) allow only a single SCI (System Control Interrupt) source hence in the multi-node a single master node issues the SCIs

- To prevent performance losses due to SCI processing the number of SCIs is limited. This mechanism must be fast enough to keep power within the allocated limits.

c. Power management across multiple nodes is managed within the voting box. A multi-node level power cap covering all nodes is best able to determine both total power and with that knowledge can determine is a single node going over a power cap will cause the system power cap to be

- even thought each node knows its power limits that can be overridden by the master BMC as long as the multi-node power limit is not exceeded.

d. Description of the Voting box is (a) each node reporting that over cap or near over cap. The Voting Box receives various power meters (but not limited to -over-all server, cpu and memory). Now determine which node is under or over the power budget.

e. A component within the voting box can act to cause a lowering of a P (Performance) state in order to save...