Prefetching apparatus, prefetching method and prefetching program product

Abstract

The efficient performance of prefetching of data prior to the reading of the data by a program. A prefetching apparatus, for prefetching data from a file to a buffer before the data is read by a program, includes: a history recorder, for recording a history for a plurality of data readings issued by the program while performing data reading; a prefetching generator, for generating a plurality of prefetchings that correspond to the plurality of data readings recorded in the history; a prefetching process determination unit, for determining, based on the history, the performance order for the plurality of prefetchings; and a prefetching unit, for performing, when following the determination of the performance order the program is executed, the plurality of prefetchings in the performance order.

1 - 18 . (canceled) 
   
   
       19 . A prefetching method, for prefetching data from a file to a buffer before the data is read by a program product, comprising:
 a history recording step of recording a history for a plurality of data readings issued by the program product while performing data reading, for each of the plurality of programs by the information processing apparatus;   a prefetching generating step of generating a plurality of prefetchings that correspond to the plurality of data readings recorded in the history, for each of the plurality of programs by the information processing apparatus;   a prefetching process determination step of employing the history to determine a performance order for the plurality of prefetchings;   a measurement step of measuring the total amount of data amount where reading is required by the program by the information processing apparatus, in response to issuing the data reading by each of the program products;   a process determination step of determining, based on the history, the performance order for the plurality of prefetchings for each of the program products, by the information processing apparatus;   a division step of dividing the plurality of prefetchings into a plurality of groups including one or more contiguous prefetchings in time-series order, for each of the product products, by the information processing apparatus;   a start condition determination step of determining a group start timing for starting one or more prefetchings included in the group in response to each of the groups for each of the program products, as a timing to read the data into a buffer until a reading start timing to start the data reading corresponding to one or more prefetchings included in the group, for each of the program products, by the information processing apparatus; and   a prefetching step of starting the performance of one or more prefetchings included in the group at the group start timing corresponding to the group, for each of the group of the program, for each of the program products, by the information processing apparatus, in response to the execution of any of the program products after the execution order and the group start timing are determined, wherein   the start condition determination step, for each of the program products, in accordance with each of the groups, is to determine the group start timing as a condition of reference data value to satisfy a total value of the data amount, and stores the prefetching order including one or more prefetching parameters included in the reference data value and the group corresponding to each of the plurality of groups, in a table within a storage device;   said measurement step is to call said prefetching step contingent on a condition that the total value of the volume of data where the executing program has requested reading exceeds a reference data value consonant with a group to be executed next; and   the prefetching step comprises:   a prefetching procedure acquiring step of acquiring said prefetching procedures for the program product among the plurality of prefetching procedures for the plurality of program products stored in the storage device, in response to the execution of any of the program products after the execution order and the group start timing have been determined, and   the prefetching execution step of executing the prefetching included in the group to be executed next according to the acquired prefetching procedures, in response to calling of the measurement unit.   
   
   
       20 . The prefetching method according to  claim 19 , wherein
 the division step is to divide the plurality of prefetchings into a plurality of groups, so that a usage rate, for the buffer, for data that have been read into the buffer by prefetching and have not yet been read from the buffer by the program product, does not exceed an upper limit value that is defined in advance; and   said start condition determination step is to determine the group start timings for the individual groups, so that the usage rate for the buffer does not exceed the upper limit value.