Prefetch command control method, prefetch command control apparatus and cache memory control apparatus
First Claim
1. A prefetch command control method comprising generating a prefetch command for data with information specifying a utilization time of the data, and scheduling an issuance timing of the prefetch command according to the information specifying the utilization time.
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Accused Products
Abstract
A prefetch command control apparatus is provided. A protocol slot generation unit, when receiving from a CPU a prefetch command in which a utilization time of data to be prefetched is specified, generates a protocol slot based on the utilization time and registers it in a schedule list storage unit. When receiving a regular access command, the protocol slot generation unit registers a protocol slot in a regular protocol queue storage unit. A cost evaluation unit evaluates an issuance cost of the prefetch command based on a cache retention time of data to be prefetched and evaluates an issuance cost of the regular access command based on a resource occupation cost. A protocol issuance unit decides which command shall be issued, the prefetch command or regular access command, based on the evaluation result of these issuance costs.
76 Citations
22 Claims
- 1. A prefetch command control method comprising generating a prefetch command for data with information specifying a utilization time of the data, and scheduling an issuance timing of the prefetch command according to the information specifying the utilization time.
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7. A prefetch command control apparatus comprising:
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a storage unit which stores a prefetch command for an external resource with information specifying data utilization time added;
a cost evaluation unit which evaluates an issuance cost which accrues due to a prefetched data staying in a cache by the specified utilization time when the stored prefetch command is issued; and
an issuance unit which adjusts a timing when the stored prefetched command is issued for the external resource according to an evaluation result by the cost evaluation unit. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A cache memory control apparatus comprising:
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a cache memory which caches data obtained from an external resource and provides the cached data to a processor;
a scheduler which schedules an access protocol for the external resource received from the processor and sets up the scheduled access protocol in a request queue for the external resource; and
an external resource controller which reads the access protocol from the request queue and accesses the external resource to provide data to the cache memory, and wherein the scheduler comprising;
a storage unit which stores a prefetch command for an external resource with information specifying data utilization time added;
a cost evaluation unit which evaluates an issuance cost which accrues due to a prefetched data staying in a cache by the specified utilization time when the stored prefetch command is issued; and
an issuance unit which adjusts a timing when the stored prefetched command is issued for the external resource according to an evaluation result by the cost evaluation unit. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A computer program executable by a computer, the program comprising:
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analyzing a source code and converting the source code into an intermediate code;
determining data to be prefetched based on the intermediate code, and then inserting an access command for the data as a prefetch command into a position before an original execution sequence position, and adding information specifying a utilization time of the data in the prefetch command; and
optimizing the intermediate code into which the prefetch command is inserted and generating an object code. - View Dependent Claims (21, 22)
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Specification