Cache memory system and processor system
First Claim
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1. A cache memory system, comprising:
- a nonvolatile memory which includes a first region and a second region, the first region storing readable and writable data, the second region storing an ECC (Error Correcting Code) for correcting an error of the data in the first region;
an error corrector which generates the ECC and carries out an error correction of the data in the first region with the ECC;
error rate determination circuitry which determines an error rate of the data in the first region;
region size adjustment circuitry which adjusts sizes of the first region and the second region inside the nonvolatile memory so that a size of one of the first region and the second region increases and a size of another of the first region and the second region decreases based on the error rate, adjusts the size of the second region to a first size when the error rate is less than a first threshold and adjusts the size of the second region to a second size which is larger than the first size when the error rate is equal to or more than the first threshold, and writes data on a lower-level memory of the nonvolatile memory when writing the data on the first region, in a case where the error rate is equal to or more than a second threshold which is larger than the first threshold; and
an access frequency measurement circuitry which measures access frequency with respect to the second region,wherein the region size adjustment circuitry shifts the second region inside the nonvolatile memory when the access frequency measured by the access frequency measurement circuitry reaches a predetermined frequency.
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Abstract
A cache memory system has a nonvolatile memory which includes a first region and a second region, the first region storing readable and writable data, the second region storing an ECC for correcting an error of the data in the first region, an error corrector which generates the ECC and carries out an error correction of the data in the first region with the ECC, error rate determination circuitry which determines an error rate of the data in the first region, and region size adjustment circuitry which adjusts a size of the second region inside the nonvolatile memory based on the error rate.
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Citations
15 Claims
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1. A cache memory system, comprising:
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a nonvolatile memory which includes a first region and a second region, the first region storing readable and writable data, the second region storing an ECC (Error Correcting Code) for correcting an error of the data in the first region; an error corrector which generates the ECC and carries out an error correction of the data in the first region with the ECC; error rate determination circuitry which determines an error rate of the data in the first region; region size adjustment circuitry which adjusts sizes of the first region and the second region inside the nonvolatile memory so that a size of one of the first region and the second region increases and a size of another of the first region and the second region decreases based on the error rate, adjusts the size of the second region to a first size when the error rate is less than a first threshold and adjusts the size of the second region to a second size which is larger than the first size when the error rate is equal to or more than the first threshold, and writes data on a lower-level memory of the nonvolatile memory when writing the data on the first region, in a case where the error rate is equal to or more than a second threshold which is larger than the first threshold; and an access frequency measurement circuitry which measures access frequency with respect to the second region, wherein the region size adjustment circuitry shifts the second region inside the nonvolatile memory when the access frequency measured by the access frequency measurement circuitry reaches a predetermined frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A processor system comprising:
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a processor; and a memory accessed by the processor, wherein the memory comprises; a nonvolatile memory which includes a first region and a second region, the first region storing readable and writable data, the second region storing an ECC (Error Correcting Code) for correcting an error of the data in the first region; an error corrector which generates the ECC and carries out an error correction of the data in the first region with the ECC; error rate determination circuitry which determines an error rate of the data in the first region; region size adjustment circuitry which adjusts sizes of the first region and the second region inside the nonvolatile memory so that a size of one of the first region and the second region increases and a size of another of the first region and the second region decreases based on the error rate, adjusts the size of the second region to a first size when the error rate is less than a first threshold and adjusts the size of the second region to a second size which is larger than the first size when the error rate is equal to or more than the first threshold, and writes data on a lower-level memory of the nonvolatile memory when writing the data on the first region, in a case where the error rate is equal to or more than a second threshold which is larger than the first threshold; and an access frequency measurement circuitry which measures access frequency with respect to the second region, wherein the region size adjustment circuitry shifts the second region inside the nonvolatile memory when the access frequency measured by the access frequency measurement circuitry reaches a predetermined frequency. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification