Electronic system and method for implementing functional redundancy checking by comparing signatures having relatively small numbers of signals

• US 6,357,024 B1
• Filed: 08/12/1998
• Issued: 03/12/2002
• Est. Priority Date: 08/12/1998
• Status: Expired due to Term

• Current Assignee: Advanced Micro Devices, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Dutton, Drew J., White, Scott A., Mudgett, Dan S.
• Primary Examiner(s): Iqbal, Nadeem
• Application Number:
  US09/132,334
• Time in Patent Office: 1,308 Days
• Field of Search: 714/45, 714/6, 714/7, 714/8, 714/10, 714/11, 714/12, 714/13, 714/25, 714/31, 714/44, 714/37, 714/43, 710/7, 710/20
• US Class Current: 714/45
• CPC Class Codes: G06F 11/1641 where the comparison is not performed by the redundant processing components
• CPC Class Codes: G06F 11/165 with continued operation after detection of the error
• CPC Class Codes: G06F 11/1654 where the output of only one of the redundant processing components can drive the attached hardware, e.g. memory or I/O
• CPC Class Codes: G06F 2201/83 the solution involving signatures

Abstract

An electronic system and method are presented for the implementation of functional redundancy checking (FRC) by comparing “signatures” produced by two different electronic devices, for example central processing units (CPUs). The signatures include a relatively small number of signals which reflect an internal state of each CPU. The electronic system includes a first and second CPU. Each CPU is configured to execute instructions and produce output signals. The first and second CPUs are preferably identical and execute instructions simultaneously such that their internal states and produced output signals should be the same at any given time. Each CPU includes a signature generator for generating the signature. The electronic system also includes a compare unit coupled to receive the signatures. The compare unit compares the signatures and produces an error signal if the signatures are not identical. The electronic system may be a computer system, further including a system bus and chip set logic. The system bus is adapted for coupling to one or more peripheral devices. The chip set logic is coupled between the first and second CPUs and the system bus, and functions as an interface between the first and second CPUs and the system bus. The first and second CPU are coupled to the chip set logic via separate processor buses. At least a portion of the signal lines of the separate processor buses are “point-to-point”, enabling the processor buses to achieve relatively high data transfer rates.

Claims

1. An electronic system, comprising:

a first and second electronic devices each configured to produce a number of output signals, wherein each electronic device includes a signature generator for generating a signature, and wherein a given signature produced by a corresponding electronic device includes a smaller number of signals than the number of output signals and is indicative of a current internal state of the corresponding electronic device; and

a compare unit coupled to receive the signatures produced by the first and second electronic devices, to compare the signatures, and to produce an error signal if the signatures are not identical.

2. The electronic system as recited in claim 1, wherein the first and second electronic devices are central processing units (CPUs) configured to execute instructions.

3. The electronic system as recited in claim 2, wherein the first and second CPUs are identical.

4. The electronic system as recited in claim 3, wherein the first and second CPUs execute instructions simultaneously.

5. The electronic system as recited in claim 2, wherein the first and second CPUs each comprise a bus interface unit (BIU) configured to produce the output signals, and wherein the signature generator within each CPU is located within the BIU.

6. The electronic system as recited in claim 2, wherein each CPU comprises a plurality of functional units, and wherein a given signature produced by a corresponding CPU is indicative of a current internal state of at least one of the functional units of the corresponding CPU.

7. The electronic system as recited in claim 2, further comprising:

a system bus adapted for coupling to one or more peripheral devices;

chip set logic coupled to the first CPU, the second CPU, and the system bus, wherein the chip set logic functions as an interface between the first and second CPUs and the system bus; and

wherein the first and second CPUs are coupled to the chip set logic by separate processor buses.

8. A computer system, comprising:

a first and second central processing unit (CPU) each configured to execute instructions, wherein each CPU comprises a bus interface unit (BIU) configured to produce output signals, and wherein each BIU includes a signature generator for generating a signature, and wherein a given signature includes a smaller number of signals than the number of output signals and is indicative of a current internal state of a corresponding one of the CPUs;

a compare unit coupled to receive the signatures produced by the first CPU and the second CPU, to compare the signatures, and to produce an error signal if the signatures are not identical;

a system bus adapted for coupling to one or more peripheral devices;

chip set logic coupled to the first CPU, the second CPU, and the system bus, wherein the chip set logic functions as an interface between the first and second CPUs and the system bus; and

wherein the first and second CPUs are coupled to the chip set logic by separate processor buses.

9. The computer system as recited in claim 8, wherein each CPU comprises a plurality of functional units, and wherein a given signature produced by a corresponding CPU is indicative of a current internal state of at least one of the functional units of the corresponding CPU.

10. A computer system, comprising:

a first and second central processing unit (CPU) each configured to execute instructions, wherein each CPU comprises a plurality of functional units and a signature generator, and wherein the signature generator is configured to generate a signature, and wherein a given signature produced by a corresponding CPU is indicative of a current internal state of at least one of the functional units of the corresponding CPU;

a compare unit coupled to receive the signatures produced by the first CPU and the second CPU, to compare the signatures, and to produce an error signal if the signatures are not identical;

a system bus adapted for coupling to one or more peripheral devices; and

chip set logic coupled to the first CPU, the second CPU, and the system bus, wherein the chip set logic functions as an interface between the first and second CPUs and the system bus; and

wherein the first and second CPUs are coupled to the chip set logic by separate processor buses.