Dynamic load-distributed computer system using estimated expansion ratios and load-distributing method therefor

• US 7,062,768 B2
• Filed: 03/21/2002
• Issued: 06/13/2006
• Est. Priority Date: 03/21/2001
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Takano, Yosuke, Kubo, Hidehito
• Primary Examiner(s): An, Meng-Ali T.
• Assistant Examiner(s): To, Jennifer N.
• Application Number:
  US10/101,882
• Publication Number:
  US 20020165900A1
• Time in Patent Office: 1,545 Days
• Field of Search: 718100-108, 709/226, 709/223
• US Class Current: 718/105
• CPC Class Codes: G06F 9/505 considering the load

Abstract

In a method for distributing a transaction in a computer system including a plurality of computers each formed by processors, a plurality of estimated loads are calculated for the computers. Then, a plurality of estimated process time expansion ratios are calculated for the computers, in accordance with the estimated loads and the numbers of processors in the computers. Then, a plurality of load indexes one for each of the computers are calculated in accordance with the estimated process time expansion ratios. Finally, the transaction is distributed in accordance with the load indexes.

Claims

1. A method for distributing a transaction in a computer system including a plurality of computers each formed by processors, comprising the steps of:

calculating a plurality of estimated loads one for each of said computers;

calculating a plurality of estimated process time expansion ratios one for each of said computers, in accordance with said estimated loads and the numbers of processors in said computers;

calculating a plurality of load indexes, one for each of said computers, in accordance with said estimated process time expansion ratios; and

distributing said transaction in accordance with said load indexes

wherein said estimated load calculating step further includes;

calculating a plurality of current loads one for each of said computers at predetermined time periods; and

calculating said estimated loads by

L_e←

a·

L_p+(1−

a)·

L_e

where L_e is an estimated load,

L_p is a current load, and

“

a”

is a definite value (0<

a≦

1)

wherein said load index calculating step calculates said load indexes each being a load index per processor in one of said computers after distributing said transaction to said computers.

2. The method as set forth in claim 1, wherein said estimated load calculating step calculates said estimated loads at predetermined time periods.

3. The method as set forth in claim 1, wherein each of said estimated loads comprises a first estimated load relating to the number of transactions currently assigned to one of said computers and a second estimated load relating to the number of transactions currently being executed in the processors of said one of said computers.

4. The method as set forth in claim 1, wherein said estimated process time expansion ratio calculating step comprises a step of correcting each of said estimated loads by the number of transactions currently assigned to said computers to obtain corrected estimated loads, so that said estimated process time expansion ratios are calculated in accordance with said corrected estimated loads and the numbers of processors in said computers.

5. The method as set forth in claim 1, wherein said load indexes are said estimated process time expansion ratios.

6. The method as set forth in claim 1, wherein said load indexes are said estimated process time expansion ratios per processor in said computers.

7. The method as set forth in claim 1, wherein said load index calculating step calculates said load indexes after distributing said transaction to said computers.

8. The method as set forth in claim 1, wherein said load index calculating step comprises the steps of:

calculating a first load index per processor in one of said computers before distributing said transaction to said computers;

calculating a second load index per processor in one of said computers after distributing said transaction to said computers; and

calculating a difference between said second and first load indexes as one of said load indexes.

9. The method as set forth in claim 1, wherein said transaction distributing step comprises the steps of:

selecting one of said computers having the minimum load index; and

causing said transaction to be processed by said one of said computers.

10. The method as set forth in claim 1, wherein said transaction distributing step comprises the steps of:

determining whether or not one of said load indexes is smaller than a threshold value; and

causing said transaction to be processed by one of said computers having said one of said load indexes, when said one of said load indexes is smaller than said threshold value.

11. The method as set forth in claim 10, wherein said threshold value is dependent upon the minimum one of said load indexes.

12. A method for distributing a transaction in a computer system including a plurality of computers each formed by processors, comprising the steps of:

calculating a plurality of estimated loads one for each of said computers;

calculating a plurality of estimated process time expansion ratios one for each of said computers, in accordance with said estimated loads and the numbers of processors in said computers;

calculating a plurality of load indexes, one for each of said computers, in accordance with said estimated process time expansion ratios; and

distributing said transaction in accordance with said load indexes

wherein said estimated load calculating step further includes;

calculating a plurality of current loads one for each of said computers at predetermined time periods; and

calculating said estimated loads by

L_e←

a·

L_p+(1−

a)·

L_e

where L_e is an estimated load,

L_p is a current load, and

“

a”

is a definite value (0<

a≦

1)

wherein said load index calculating step calculates said load indexes each being a load index per processor in one of said computers before distributing said transaction to said computers.

13. The method as set forth in claim 12, wherein said estimated load calculating step calculates said estimated loads at predetermined time periods.

14. The method as set forth in claim 12, wherein each of said estimated loads comprises a first estimated load relating to the number of transactions currently assigned to one of said computers and a second estimated load relating to the number of transactions currently being executed in the processors of said one of said computers.

15. The method as set forth in claim 12, wherein said estimated process time expansion ratio calculating step comprises a step of correcting each of said estimated loads by the number of transactions currently assigned to said computers to obtain corrected estimated loads, so that said estimated process time expansion ratios are calculated in accordance with said corrected estimated loads and the numbers of processors in said computers.

16. The method as set forth in claim 12, wherein said load indexes are said estimated process time expansion ratios.

17. The method as set forth in claim 12, wherein said load indexes are said estimated process time expansion ratios per processor in said computers.

18. The method as set forth in claim 12, wherein said load index calculating step calculates said load indexes after distributing said transaction to said computers.

19. The method as set forth in claim 12, wherein said load index calculating step comprises the steps of:

calculating a first load index per processor in one of said computers before distributing said transaction to said computers;

calculating a second load index per processor in one of said computers after distributing said transaction to said computers; and

calculating a difference between said second and first load indexes as one of said load indexes.

20. The method as set forth in claim 12, wherein said transaction distributing step comprises the steps of:

selecting one of said computers having the minimum load index; and

causing said transaction to be processed by said one of said computers.

21. The method as set forth in claim 12, wherein said transaction distributing step comprises the steps of:

determining whether or not one of said load indexes is smaller than a threshold value; and

causing said transaction to be processed by one of said computers having said one of said load indexes, when said one of said load indexes is smaller than said threshold value.

22. A load-distributed computer system comprising:

a plurality of computers each including processors;

a relay distributing unit for receiving a message for requesting a transaction process; and

a channel communication network connected between said computers and said relay distributing unit,

each of said computers comprising;

a first load data measuring unit for measuring a load of said each of said computers;

a transaction processing unit for processing transactions,

said relay distributing unit comprising;

a second load data measuring unit for receiving said load to calculate an estimated load in accordance with said load;

a load data storing unit for storing said estimated load data;

an executing computer selecting unit for calculating a plurality of estimated process time expansion ratios one for each of said computers, in accordance with said stored estimated load and the number of processors in each of said computers, calculating a plurality of load indexes, one for each of said computers, in accordance with said estimated process time expansion ratios, selecting one of said computers having the minimum load index in accordance with said load indexes, and causing said transaction process to be processed by said transaction processing unit of said selected computer

wherein said second load data measuring unit comprises;

a section adapted to calculate a plurality of current loads one for each of said computers at predetermined time periods; and

a section adapted to calculate said estimated loads by

L_e←

a·

L_p+(1−

a)·

L_e

where L_e is an estimated load,

L_p is a current load, and

“

a”

is a definite value (0<

a≦

1).

23. The system as set forth in claim 22, wherein said second load data measuring unit calculates said estimated loads at predetermined time periods.

24. The system as set forth in claim 22, wherein each of said estimated loads comprises a first estimated load relating to the number of transactions currently assigned to one of said computers and a second estimated load relating to the number of transactions currently being executed in the processors of said one of said computers.

25. The system as set forth in claim 22, wherein said executing computer selecting unit comprises a section adapted to correct each of said estimated loads by the number of transactions currently assigned to said computers to obtain corrected estimated loads, so that said estimated process time expansion ratios are calculated in accordance with said corrected estimated loads and the numbers of processors in said computers.

26. The system as set forth in claim 22, wherein said load indexes are said estimated process time expansion ratios.

27. The system as set forth in claim 22, wherein said load indexes are said estimated process time expansion ratios per processor in said computers.

28. The system as set forth in claim 22, wherein said executing computer selecting unit calculates said load indexes after distributing said transaction to said computers.

29. The system as set forth in claim 22, wherein said executing computer selecting unit calculates said load indexes each being a load index per processor in one of said computers after distributing said transaction to said computers.

30. The system as set forth in claim 22, wherein said executing computer selecting unit calculates said load indexes each being a load index per processor in one of said computers before distributing said transaction to said computers.

31. The system as set forth in claim 22, wherein said executing computer selecting unit comprises:

a section adapted to calculate a first load index per processor in one of said computers before distributing said transaction to said computers;

a section adapted to calculate a second load index per processor in one of said computers after distributing said transaction to said computers; and

a section adapted to calculate a difference between said second and first load indexes as one of said load indexes.

32. The system as set forth in claim 22, wherein said executing computer selecting unit comprises:

a section adapted to select one of said computers having the minimum load index; and

a section adapted to cause said transaction to be processed by said transaction processing unit of said one of said computers.

33. A load-distributed computer system comprising:

a plurality of computers each including processors each for receiving a message for requesting a transaction process; and

an exchange/store unit connected to said computers,

each of said computers comprising;

a first load data measuring unit for measuring a load of said each of said computers;

a transaction processing unit for processing transactions,

a second load data measuring unit for receiving said load to calculate an estimated load in accordance with said load;

a load data storing unit for storing said estimated load data;

an executing computer selecting unit for calculating a plurality of estimated process time expansion ratios one for each of said computers, in accordance with said stored estimated load and the number of processors in each of said computers, calculating a plurality of load indexes, one for each of said computers, in accordance with said estimated process time expansion ratios, determining whether or not said each of said computers is to process said transaction process in accordance with said load indexes, causing said transaction process to be processed by said transaction processing unit when said each of said computers is to process said transaction process, and transmitting said message via said exchange/store unit to another computer when said each of said computer is not to process said transaction process

wherein said second load data measuring unit comprises;

means for a section calculating a plurality of current loads one for each of said computers at predetermined time periods; and

means for calculating said estimated loads by

L_e←

a·

L_p+(1−

a)·

L_e

where L_e is an estimated load,

L_p is a current load, and

“

a”

is a definite value (0<

a≦

1).

34. The system as set forth in claim 33, wherein said second load data measuring unit calculates said estimated loads at predetermined time periods.

35. The system as set forth in claim 33, wherein each of said estimated loads comprises a first estimated load relating to the number of transactions currently assigned to one of said computers and a second estimated load relating to the number of transactions currently being executed in the processors of said one of said computers.

36. The system as set forth in claim 33, wherein said executing computer selecting unit comprises means for correcting each of said estimated loads by the number of transactions currently assigned to said computers to obtain corrected estimated loads, so that said estimated process time expansion ratios are calculated in accordance with said corrected estimated loads and the numbers of processors in said computers.

37. The system as set forth in claim 33, wherein said load indexes are said estimated process time expansion ratios.

38. The system as set forth in claim 33, wherein said load indexes are said estimated process time expansion ratios per processor in said computers.

39. The system as set forth in claim 33, wherein said executing computer selecting unit calculates said load indexes after distributing said transaction to said computers.

40. The system as set forth in claim 33, wherein said executing computer selecting unit calculates said load indexes each being a load index per processor in one of said computers after distributing said transaction to said computers.

41. The system as set forth in claim 33, wherein said executing computer selecting unit calculates said load indexes each being a load index per processor in one of said computers before distributing said transaction to said computers.

42. The system as set forth in claim 33, wherein said executing computer selecting unit comprises:

a section adapted to calculate a first load index per processor in one of said computers before distributing said transaction to said computers;

a section adapted to calculate a second load index per processor in one of said computers after distributing said transaction to said computers; and

a section adapted to calculate a difference between said second and first load indexes as one of said load indexes.

43. The system as set forth in claim 33, wherein said executing computer selecting unit comprises a section adapted to determining whether or not one of said load indexes is smaller than a threshold value, thus determining whether or not said each of said computers is to process said transaction process.

44. The system as set forth in claim 43, wherein said threshold value is dependent upon the minimum one of said load indexes.

45. The system as set forth in claim 33, further comprising a relay provisional-distributing unit, connected to said computers, for statically or quasi-statically distributing said message to said computers.

46. The system as set forth in claim 45, wherein said relay provisional-distributing unit distributes said message to said computers by dividing a plurality of terminal units connected to said relay provisional-distributing unit into a plurality of groups each corresponding to one of said computers.

47. The system as set forth in claim 45, wherein said relay provisional-distributing unit distributes said message to said computers by sequentially said message to said computers in accordance with the numbers of processors therein.

48. The system as set forth in claim 45, wherein said relay provisional-distributing unit stochastically distributes said message to said computers.