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Checkstop-on-Stop Capability for Multiprocessor Debug

IP.com Disclosure Number: IPCOM000112250D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Brooks, JS: AUTHOR

Abstract

This article describes a multiprocessor debug technique that enables any processor in the system, when stopped, to stop all other processors, thus providing a useful tool for hardware and software debug in a multiprocessor environment.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 61% of the total text.

Checkstop-on-Stop Capability for Multiprocessor Debug

      This article describes a multiprocessor debug technique that
enables any processor in the system, when stopped, to stop all other
processors, thus providing a useful tool for hardware and software
debug in a multiprocessor environment.

      A multiprocessor system containing processors that have no
means of receiving and responding to the stopped condition of another
processor in the system can hinder hardware and software debug.
Debug can be hindered because it isn't possible to observe the state
of all processors immediately following a condition that caused one
processor to stop, such as an instruction address compare
(breakpoint).  Ideally, a processor could signal all other processors
that it has stopped, and in turn, each processor would stop.  Some
processors, for example, provide a function whereby prior to
stopping, the processor sends a quiesce request to the system, and
waits for a "system quiesced" response back from the system.  This
technique allows the system chips to respond to the stopped condition
of the processor, but it can't necessarily be used to stop other
processors in the system, because the processors may not have a
quiesce request input pin, and may be unaware that the system is
stopping.

      The checkstop-on-stop technique allows any processor, upon
stopping, to checkstop all other processors in the system.  The state
of each processor can then be examined.  To impl...