Method and system for performing real-time operation

• US 7,685,599 B2
• Filed: 09/08/2004
• Issued: 03/23/2010
• Est. Priority Date: 09/26/2003
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kanai, Tatsunori, Maeda, Seiji, Yano, Hirokuni, Yoshii, Kenichiro
• Primary Examiner(s): An; Meng-Ai
• Assistant Examiner(s): ARCOS, CAROLINE H
• Application Number:
  US10/935,188
• Publication Number:
  US 20050108715A1
• Time in Patent Office: 2,022 Days
• Field of Search: 718/100, 718/102, 718/104, 718/107, 709/225, 709/226, 709/233, 710/33, 370/395.4
• US Class Current: 718/104
• CPC Class Codes: G06F 9/4881 Scheduling strategies for dispatcher, e.g. round robin, multi-level priority queues

Abstract

An information processing system performs a plurality of tasks within a specific time interval. The system includes a bus, a plurality of processors which transfer data via the bus, and a unit for performing a scheduling operation of determining execution start timing of each of the tasks and at least one the processors which executes the tasks, based on cost information concerning a time required to perform each of the tasks and bandwidth information concerning a data transfer bandwidth required by each of the tasks, to perform the tasks within the specific time interval without overlapping execution terms of at least two tasks of the tasks, the two tasks requiring data transfer bandwidths not less than those of the others of the tasks.

Claims

1. A method of performing a plurality of tasks within a specific time interval using a first processor and a second processor which transfer data via a bus, the method comprising:

inputting cost information concerning a time required to perform each of the plurality of tasks and bandwidth information concerning a data transfer bandwidth required by each of the plurality of tasks;

performing a scheduling operation of determining execution start timing of each of the plurality of tasks and at least one of the processors which executes the plurality of tasks, based on the input cost information and bandwidth information, to perform the plurality of tasks within the specific time interval without overlapping execution terms of at least two tasks of the plurality of tasks, said at least two tasks requiring data transfer bandwidths not less than data transfer bandwidths of other tasks of the plurality of tasks wherein the performing of the scheduling operation includes (a) assigning a first task and a second task of said at least two tasks to the first processor and the second processor, respectively, and (b) determining execution start timing of the first task assigned to the first processor and execution start timing of the second task assigned to the second processor, to execute the first task and the second task without overlapping execution terms of the first task and the second task;

computing a peak value of data transfer bandwidth of data transfer to be performed by the first processor and the second processor within the specific time interval, based on the execution start timing and the execution term of each of the plurality of tasks and the bandwidth information; and

setting a data transfer speed of the bus at a value that is lower than a maximum data transfer bandwidth of the bus based on a ratio of the computed peak value to the maximum data transfer bandwidth.

2. The method according to claim 1, wherein the setting includes controlling an operating frequency of the bus.

3. An information processing system that performs a plurality of tasks within a specific time interval, comprising:

a bus;

a first processor and a second processor which transfer data via the bus; and

means for performing a scheduling operation of determining execution start timing of each of the plurality of tasks and at least one of the processors which executes the plurality of tasks, based on cost information concerning a time required to perform each of the plurality of tasks and bandwidth information concerning a data transfer bandwidth required by each of the plurality of tasks, to perform the plurality of tasks within the specific time interval without overlapping execution terms of at least two tasks of the plurality of tasks, said at least two tasks requiring data transfer bandwidths not less than data transfer bandwidths of other tasks of the plurality of tasks, wherein the performing of the scheduling operation includes (a) assigning a first task and a second task of said at least two tasks to the first processor and the second processor, respectively, and (b) determining execution start timing of the first task assigned to the first processor and execution start timing of the second task assigned to the second processor, to execute the first task and the second task without overlapping execution terms of the first task and the second task;

means for computing a peak value of data transfer bandwidth of data transfer to be performed by the first processor and the second processor within the specific time interval, based on the execution start timing and the execution term of each of the plurality of tasks and the bandwidth information; and

means for setting a data transfer speed of the bus at a value that is lower than a maximum data transfer bandwidth of the bus based on a ratio of the computed peak value to the maximum data transfer bandwidth.

4. The information processing system according to claim 3 wherein the means for setting the data transfer speed includes means for controlling an operating frequency of the bus.

5. The information processing system according to claim 3, wherein the bus includes an inter-connection network.

6. The information processing system according to claim 3, further comprising a memory connected to the bus, and

wherein the processors are configured to transfer data between the processors and the memory via the bus.

7. A computer-readable storage media encoded with a computer readable program configured to cause an information processing apparatus to execute a method of performing a plurality of tasks within a specific time interval, the computer including a first processor and a second processor which transfer data via a bus, the method comprising:

inputting cost information concerning a time required to perform each of the plurality of tasks and bandwidth information concerning a data transfer bandwidth required by each of the plurality of tasks;

performing a scheduling operation of determining execution start timing of each of the plurality of tasks and at least one of the processors which executes the plurality of tasks, based on the input cost information and bandwidth information, performing the plurality of tasks within the specific time interval without overlapping execution terms of at least two tasks of the plurality of tasks, said at least two tasks requiring data transfer bandwidths not less than data transfer bandwidths of other tasks of the plurality of tasks, wherein

the performing of the scheduling operation includes (a) assigning a first task and a second task of said at least two tasks to the first processor and the second processor, respectively, and (b) determining execution start timing of the first task assigned to the first processor and execution start timing of the second task assigned to the second processor, to execute the first task and the second task without overlapping execution terms of the first task and the second task;

computing a peak value of data transfer bandwidth of data transfer to be performed by the first processor and the second processor within the specific time interval, based on the execution start timing and the execution term of each of the plurality of tasks and the bandwidth information; and

setting a data transfer speed of the bus at a value that is lower than a maximum data transfer bandwidth of the bus based on a ratio of the computed peak value to the maximum data transfer bandwidth.

8. The computer-readable storage media according to claim 7, wherein the setting the data transfer speed includes controlling an operating frequency of the bus.