Bus master read request adaptive prefetch prediction method and apparatus

An apparatus for predicting quantities of data that will be required in a transfer of data from a storage device, comprising:

• logic to monitor patterns of quantities of data transferred in at least two earlier transfers of data from the storage device to a requesting device capable of initiating a request for data from the storage device;
• logic to use at least one pattern to make a prediction of a quantity of data that will be required in a future transfer of data from the storage device to a requesting device that occurs after a future reoccurrence of a pattern of quantities of data transferred, and associating that prediction with that pattern;
• logic to use a prediction to read a quantity of data from the storage device in response to a request from a requesting device for an unspecified quantity of data from the storage device;
• and
• logic to selectively modify a prediction after two or more occasions in which the prediction proves to be inaccurate.

Art apparatus for predicting quantities of data that will be required in a transfer of data from a storage device, wherein the apparatus is incorporated into a bus interface for a first bus that supports at least one type of transfer in which the quantity of data to be transferred cannot be specified, the apparatus comprising:

• logic to monitor patterns of quantities of data transferred in at least two earlier transfers of data from the storage device to a requesting device capable of initiating a request for data from the storage device;
• logic to use at least one pattern to make a prediction of a quantity of data that will be required in a future transfer of data from the storage device to a requesting device that occurs after a future reoccurrence of a pattern of quantities of data transferred, and associating that prediction with that pattern;
• logic to use a prediction to read a quantity of data from the storage device in response to a request from a requesting device for an unspecified quantity of data from the storage device;
• and
• logic to selectively modify a prediction if the prediction proves to be inaccurate.

A computer system, comprising:

• at least one CPU;
• at least one storage device;
• at least one bus supporting a type of transfer of data in which the quantity of data cannot be specified when a request for data is initiated;
• at least one requesting device coupled to the bus and capable of initiating a request for data from the storage device;
• and
• prediction logic to predict the quantity of data that will be required to satisfy a request for data based on patterns of quantities of data transferred from the storage device to one or more requesting devices in response to earlier requests for data from the storage device wherein a prediction is modified after two or more occasions in which the prediction proves to be inaccurate.

A computer system, comprising:

• at least one CPU;
• at least one storage device;
• at least one bus supporting a type of transfer of data in which the quantity of data cannot be specified when a request for data is initiated;
• at least one requesting device coupled to the bus and capable of initiating a request for data from the storage device;
• and
• prediction logic incorporated into a bus interface coupled to the at least one bus to predict a quantity of data that will be required to satisfy a request for data based on patterns of quantities of data transferred in at least two earlier transfers from the storage device to the at least one requesting device in response to earlier requests for data from the storage device, and to use a prediction to read a quantity of data from the storage device to the at least one requesting device.