PARALLEL COMPUTER SYSTEM AND PROGRAM

• US 20120254881A1
• Filed: 04/02/2012
• Published: 10/04/2012
• Est. Priority Date: 04/04/2011
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: HAMAMOTO, Masaki, YAMADA, Tetsuya, TOMODA, Atsushi, MIYAMOTO, Atsushi
• Granted Patent: US 9,043,804 B2
• Time in Patent Office: Days
• US Class Current: 718/102
• CPC Class Codes: G06F 9/4887 involving deadlines, e.g. rate based, periodic
• CPC Class Codes: G06F 9/522 Barrier synchronisation

Abstract

There is provided a parallel computer system for performing barrier synchronization using a master node and a plurality of worker nodes based on the time to allow for an adaptive setting of the synchronization time. When a task process in a certain worker node has not been completed by a worker determination time, the particular worker node performs a communication to indicate that the process has not been completed, to a master node. When the communication has been received by a master determination time, the master node performs a communication to indicate that the process time is extended by a correction process time, in order to adjust and extend the synchronization time. In this way, it is possible to reduce the synchronization overhead associated with the execution of an application with a relatively large variation in the process time from a synchronization point to the next synchronization point.

Claims

1. A parallel computer system for performing parallel computation by connecting a plurality of computing units via a network,

wherein the computing unit serves as a master node for performing synchronization process or as a worker node for performing task process,

wherein the master node includes:

setting a master determination time with the expectation that the task process in all the worker nodes is completed within a basic process time;

transmitting a process start notification to the plurality of worker nodes;

checking whether a process-not-completed notification is received from the worker node at the master determination time;

when the process-not-completed notification is received, transmitting a process extension notification to the plurality of worker nodes; and

when the process-not-completed notification is not received, transmitting a synchronization completion notification to the plurality of worker nodes;

wherein the worker node includes;

setting a worker determination time by using the basic process time when the process start notification or the synchronization completion notification is received from the master node;

when the task process is not completed at the worker determination time, transmitting the process-not-completed notification to the master node; and

when the task process is completed, waiting for the synchronization completion notification from the master node.

2. The parallel computer system according to claim 1,

wherein when the task process in at least one of the worker nodes has not been completed by the basic process time, the master node redefines the master determination time by using a correction process time,

wherein when the process extension notification is received from the master node, the worker node redefines the worker determination time by using the correction process time.

3. The parallel computer system according to claim 2,

wherein the master node transmits the synchronization completion notification or the process start notification, together with the information on the basic process time,

wherein the master node transmits the process extension notification together with the information on the correction process time.

4. The parallel computer system according to claim 2,

wherein the master node can update the value of the basic process time or correction process time.

5. The parallel computer system according to claim 1,

wherein the computing unit includes a plurality of communication control units connected to a processor, a storage unit, and the network.

6. The parallel computer system according to claim 5,

wherein one of the communication control units is used for transmitting and receiving the process start notification, the process-not-completed notification, the process extension notification, and the synchronization completion notification between the master node and the worker node.

7. The parallel computer system according to claim 5,

wherein the storage unit of the computing unit includes a memory area for storing master/worker information to identify whether the particular computing unit is the master node or the worker node.

8. The parallel computer system according to claim 7,

wherein the computing unit receives a program to be executed by the worker node from the computing unit serving as the master node, and stores the master/worker information in the memory area.

9. A program executed by a processor of a parallel computer system for performing parallel computation by connecting a plurality of computing units via a network,

wherein the computing unit includes the processor and a storage unit, serving as a master node for performing synchronization process or as a worker node for performing task process,

wherein the program causes the processor of the computing unit serving as the master node to perform the steps of:

setting a master determination time with the expectation that the task process in all the worker nodes is completed within a basic process time;

transmitting a process start notification to the plurality of worker nodes;

checking whether a process-not-completed notification is received from the worker node at the master determination time,

when the process-not-completed notification is received, transmitting a process extension notification to the plurality of worker nodes; and

when the process-not-completed notification is not received, transmitting a synchronization completion notification to the plurality of worker nodes,

wherein the program causes the computing unit serving as the worker node to perform the steps of;

setting a worker determination time by using the basic process time when the process start notification or the synchronization completion notification is received from the master node;

when the task process is not completed at the worker determination time, transmitting the process-not-completed notification to the master node; and

when the task process is completed, waiting for the synchronization completion notification from the master node.

10. The program according to claim 9,

wherein when the task process in at least one of the worker nodes has not been completed by the basic process time, the program causes the processor of the computing unit serving as the master node to redefine the master determination time by using a correction process time,

wherein when the process extension notification is received from the master node, the program causes the processor of the computing unit serving as the worker node to redefine the worker determination time by using the correction process time.

11. The program according to claim 10,

wherein the program causes the processor of the computing unit serving as the master node to perform the steps of:

transmitting the synchronization completion notification or the process start notification, together with the information on the basic process time; and

transmitting the process extension notification together with the information on the correction process time.

12. The program according to claim 10,

wherein the program causes the processor of the computing unit serving as the master node to update the value of the basic process time or correction process time by a predetermined calculation method.

13. The program according to claim 9,

wherein the program causes the processor of the computing unit to store master/worker information in the storage unit to identify whether the particular computing unit is the master node or the worker node.

14. The program according to claim 13,

wherein the program causes the processor of the computing unit serving as the master node to transmit a program to be executed by the worker node and the initial value of the program, to the computing unit serving as the worker node.

15. The program according to claim 14,

wherein when the program and the initial value of the program are received, the program causes the processor of the computing unit serving as the worker node to store the master/worker information indicating the worker node into the storage unit.