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Method to ensure that the Converged Service Processor will act on only one mailbox request for duplicate requests.

IP.com Disclosure Number: IPCOM000019305D
Original Publication Date: 2003-Sep-10
Included in the Prior Art Database: 2003-Sep-10
Document File: 1 page(s) / 40K

Publishing Venue

IBM

Abstract

Disclosed is the method for the Converged Service Processor (CSP) will act on only one mailbox request for duplicate requests.

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  Method to ensure that the Converged Service Processor will act on only one mailbox request for duplicate requests.

Run Time Abstraction Services (RTAS) or Hypervisor make different types of mailbox requests to CSP to perform various actions. For certain particular mailbox requests, CSP should take action on only one mailbox request, even if the RTAS/Hypervisor sends the same request again. Under certain circumstances, if the mailbox response from the CSP is lost, then RTAS/Hypervisor might send the same mailbox request again. If CSP has already processed this mailbox request, then it should ignore the duplicate request. For example, in case of processor hot sparing, RTAS/Hypervisor sends a grant cpu mailbox command to CSP. If the CSP starts an unlicensed processor after receiving this request, but somehow RTAS/Hypervisor did not receive a successful acknowledgement from CSP, then it will send the request again. Under these circumstances, the CSP should not license extra processors since it already honored the first request.

The method used to circumvent this problem is by using sequence number scheme. This method works as explained below:

A global variable is maintained for a sequence number. RTAS/Hypervisor will send

the sequence number and partition ID as a part of mailbox request to CSP. Upon receiving the mailbox request, CSP will license a new processor and stores

away the partiton ID and sequence number. If RTAS/Hypervisor receives the acknowledgement from...