System for assigning boot strap processor in symmetric multiprocessor computer with watchdog reassignment

• US 5,860,002 A
• Filed: 07/12/1996
• Issued: 01/12/1999
• Est. Priority Date: 07/12/1996
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Huang, Arthur
• Primary Examiner(s): Kriess, Kevin A.
• Application Number:
  US08/678,891
• Time in Patent Office: 914 Days
• Field of Search: 395/651, 395/652, 395/653, 395/200.5, 395/200.51, 395/200.52, 395/712
• US Class Current: 713/2
• CPC Class Codes: G06F 15/177 Initialisation or configuration control processor initialisation G06F9/4405
• CPC Class Codes: G06F 9/4405 Initialisation of multiprocessor systems
• CPC Class Codes: G06F 9/50 Allocation of resources, e.g. of the central processing unit [CPU]

Abstract

A boot strap assignment system is disclosed for a symmetric multiprocessor computer in which the role of the boot strap processor is assigned to one of the working processors by a central agent as part of power-on configuration. The system includes a system management processor which monitors the operation of the multiprocessor computer and controls a switching circuit that selectively transmits the boot strap assignment signal from the central agent to the working processors. Since the management processor monitors environmental conditions and shut-down events, it can predict the failure of working processors and assign the bootstrapping function appropriately. A watch dog timer is also provided in case the bootstrapping fails so that another working processor can be assigned the task of booting up the computer.

Claims

1. A method of assigning a bootstrapping among multiple working processors in a multiprocessor computer in which a central agent generates a boot strap assignment signal, the method comprising

intercepting the boot strap assignment signal from the central agent;

determining which of the multiple working processors should perform the bootstrapping; and

transmitting the boot strap assignment signal among the working processors so that the determined one of the working processors is signaled to perform the bootstrapping.

2. A method as described in claim 1, further comprising transmitting the boot strap assignment signal to one of a plurality of bus request lines that are rotated between the working processors.

3. A method as described in claim 1, wherein transmitting the boot strap assignment signal to the working processors comprises:

receiving the boot strap assignment signal at a plurality of switches that connect to the separate bus request lines that pass between the working processors; and

selectively closing one of the switches to pass the boot strap assignment signal to only one of the bus request lines.

4. A method as described in claim 1, further comprising determining which of the multiple working processors should perform bootstrapping in response to environmental conditions for the computer and previous shut-down events.

5. A method as described in claim 1, further comprising generating a boot strap assignment signal in a bus arbitration controller.

6. A method as described in claim 1, further comprising:

activating a watch dog timer in response to reset; and

resetting the watch dog timer upon finishing bootstrapping the multiprocessor computer.

7. A method as described in claim 6, further comprising assigning a new processor as the boot strap processor in response to the watch dog timer timing-out after the previous boot strap processor failed to boot strap the multiprocessor computer.