JPH0388060A - Load distribution control system - Google Patents

Abstract

PURPOSE:To improve system efficiency by shortening overhead in load distribution control processing. CONSTITUTION:When a task start request is generated in a multisite system for executing load distribution, a processor 1a e.g. requests the start of other processors 1b, 1c in the sites (b), (c) of small load states if the load state of the request generation site ( self-site) (a) of the processor 1a is higher than a previously determined value. Respective sites (a) to (c) store the load of other sites and decides the sites of small load. Respective sites obtain the load information of other sites by overhead reduced as less as possible, so as to reflect the practical load states of respective sites whose information is monetarily changed and holds the site of the smallest load site out of the stored load information of other sites so as not to be different from the practical site of the smallest load. Consequently, the efficiency of the whole system can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a load distribution control method in a multi-site system in which multiple computers (referred to as multi-site) process multiple tasks.

(Prior art) In recent years, with the diversification of requirements for computer systems and the advancement of technology, these systems have tended to become larger and more complex, and there has been a demand for processing systems that can perform various tasks in a distributed manner. is increasing.

For this reason, it is important to perform load distribution control that determines which site processes tasks submitted to the system, taking into account the efficiency of the entire system.

By the way, in conventional load distribution control, in order to know the load on each site that changes from moment to moment, the load status of each site (hereinafter simply referred to as load) is periodically broadcast and communicated, and this is stored at each site. Techniques such as keeping it in place have been taken.

However, if the frequency of communication to convey the load increases, the overhead due to communication and updating of the stored load of each site will increase, and conversely, if the frequency of communication to convey the load decreases, the actual load will increase. and:c! This solves the problem that the system efficiency decreases because there is a mismatch in the stored load, and tasks are concentrated on sites with a high load, or tasks are not distributed to sites with a low load. arise.

(Problem to be solved by the invention) As described above, in the conventional load distribution control method described above,
Overhead in load distribution control processing increases, which impedes improvement in system efficiency.

The present invention has been made in response to such circumstances, and an object of the present invention is to provide a load distribution control method that can improve system efficiency by reducing the overhead in load distribution control processing.

[Configuration of the Invention (Means for Solving the Problem) The load distribution control method according to claim 1 has a plurality of sites for processing a plurality of tasks, and each site has a current load of its own site. It has the function of determining the status, transmitting the load status to other sites, and storing the load status of other sites.In a multi-site system that distributes the load, when a task start request occurs, the local site determines whether the load status of the site has reached a predetermined load status limit, and if the load status of the local site is smaller than the load status stored at another site, and if the load status of the local site exceeds the load limit. If the load state exceeds the load limit and is smaller than the load state stored on the other site, the task is started on the local site and executed, and the load state on the local site exceeds the load limit and is smaller than the load state stored on the other site. If there is a load state that is smaller than the load state of the own site, the site with the smallest load state among the remembered load states of other sites is set as the task start request destination site, and the task is started on the own site. Communication information consisting of a request source site, a task activation request destination site identifier, a task activation request source site identifier, a task activation request source's load status, a memorized task activation request destination site's load status, and a task activation request, Broadcast communication is sent to all sites as a task start request communication, and when the task start request communication is received, the load status of the task start requesting site is updated to the sent load condition, and the own site is activated to perform the task. If the site is the activation request destination, the task is activated and executed.

The load distribution control method according to claim 2 has a plurality of sites for processing a plurality of tasks, each site determines the current load state of its own site, and transmits the load state to other sites, It has a function to remember the load status of other sites, and in a multi-site system where load distribution is distributed, when your own site recognizes the load status of other sites, the load status of your own site will be changed to that of the other site. If it is smaller than the load status, the site is designated as a load reduction site, and the load reduction site identifier and the load status of the load reduction site are broadcasted to all sites as a load reduction notification communication, and when the load reduction notification communication is received, The stored load status of the load reduction site is updated to the sent load status.

(Function) In the load distribution control method according to claim 1, when a task activation request occurs and the load state of the request generating site (referred to as the local site) is higher than a predetermined value, other load states are Make a startup request on a site with few users. At this time, each site remembers the load of other sites,
This is used to determine which sites have the least load. In addition, the load information of other sites is calculated with as little overhead as possible, and the information reflects the actual load status of each site that changes from moment to moment, and the load information of other sites that is remembered as the site with the lowest load is calculated. By ensuring that the least loaded site remains consistent, the overall efficiency of the system is increased.

In other words, each site has the function of storing the load status of other sites and the function of determining the current load status of its own site.

When a task start request occurs, it is determined whether the load status of the own site has reached a predetermined load limit, and if the load status of the own site is smaller than the load status stored at another site, the load status of the own site is determined. If the load status exceeds the load limit and is smaller than the load status stored at the other site, the task will be started and executed at the local site, and if the load status at the local site exceeds the load limit and is smaller than the load status stored at the other site. If there is a load state that is smaller than the load state of the own site among the stored load states, the task launch request destination is the site with the smallest load state among the stored load states of other sites. The task start request destination site identifier, the task start request source site identifier, the load of the task start request source, the remembered load of the task start request destination site, and the task start request site, with the own site as the task start request source site. 5 are broadcasted to all sites as task activation request communications.

This task activation request communication is originally necessary for the task activation request, and does not result in an increase in communication overhead.

When the local site receives a task activation request communication from another site, it updates the stored load status of the task activation request source site to the load status sent, and further updates the local site to the task activation request destination site. If so, start and execute the task.

In the load distribution control method according to claim 2, when receiving the task activation request communication, each site can know the load status of the task activation request destination that is considered to have the lowest load status, so that the load on the own site can be reduced. Compare the status with the load status of the destination of the task start request sent, and if the load status of the local site is smaller, set the local site as the load reduction site and use the load reduction site identifier and the load status of the load reduction site as the load reduction site. Broadcast communication to all sites as a reduction notification communication. Although this load reduction notification communication increases communication overhead,
This communication occurs when the actual load state of the local site is smaller than the stored minimum load state, that is, the site with the stored minimum load state differs from the site with the actual minimum load state. This is the minimum communication required to correct this.

Then, each site that receives the load reduction notification communication updates the stored load state of the load reduction site to the sent load state.

Therefore, it is possible to maximize system efficiency with only the minimum amount of communication and associated processing overhead.

(Example) Hereinafter, details of an example of the present invention will be described based on the drawings.

FIG. 1 shows the configuration of a multi-site system according to the load distribution control method of the present invention.

In the figure, la, lb, and lc are processors 2a, 2b, and 2b, each having a function of determining the current load state of its own site, transmitting the load to other sites, and storing the load of other sites.
2e each indicates a communication device as a broadcast communication means.

Pairs of processors la, lb, and lc and communication devices 2a, 2b, and 2c constitute sites a, b, and c.

Next, the operation of such a tRhl multi-site system will be explained using FIGS. 2 to 10.

First, in the load distribution control method in this embodiment, each processor la, lb, lc operates as shown in FIG. At the time of reception via the communication device 2, the operation is performed as shown in FIG. 9, and the load reduction notification communication is sent to each communication device 2a, 2b.

At the time of reception via 2c, the operation is as shown in FIG. FIG. 2 shows each processor la and lb.

It shows the processing capacity of 1c, and represents the amount of 111 that can be processed per unit square hour.

Figure 3 shows the task start request generation time, the processor that generated the task start request, and the workload of the task corresponding to each task number when a task start request occurs in each processor la, lb, and lc. is the number of tasks activated at each point in time, and a value of 2 is used as the predetermined load limit.

FIG. 4 shows the state of tasks activated in each processor la, lb, and lc, and FIG. 5 shows the actual negative state? , :j and the load of other sites stored at each site are shown.

First, at time 0 in processor 1a, task number l is
When a startup request occurs, it is determined whether the load on the local site has reached a predetermined load limit, or whether the load on the local site is smaller than the load on other sites (step 801), and the load limit has been reached. If the load has been reached and the load on the local site is smaller than the load on the other sites, the local site starts and executes (step 802).

On the other hand, if the load limit has not been reached and the load on the local site is not smaller than the load on other sites, the site with the lowest load among the stored loads on other sites is selected as the task activation request destination site. The task start request site number of the task start request destination site, the task start request source site number, the load of the task start request source, the load of the task start request destination site that is remembered, and the task start request are set as the task start request source site of the own site. Broadcast communication is made to all sites as a request communication (step 803).

Similarly, task numbers 2 to 7 are activated and executed at the activation request generating site.

At time 7, for example, the processor 1b executes a task.
When the startup request No. 8 occurs, the load 2 of the own site has reached the predetermined load limit 2, and the stored load of another site is smaller than the load of the own site ( As shown in FIG. 5, both sites a and b are O) (step 80t), so site a, which has the smallest load among the other sites and loads stored at this point, is set as the task start request destination site, and Assuming that site b is the task start request source site, the task start request destination site identifier b1, the load 2 of the task start request source, the stored load 0 of the task start request destination site, and the start request of task 8 are all sent as task start request communications. Broadcast communication to the site (step 803)
).

The processor 1a that receives this task activation request communication via the communication device 2a updates the stored load 0 of the task activation requesting site b to the sent value 2 (step 901), and starts the task at its own site a. It is determined whether the request destination site is a (step 902).

If it is determined that the task start request destination is site a,
After starting task 8 and executing it (step 903), it is determined whether the load 2 of the local site a is smaller than the load 0 of the destination of the task start request sent (step 90).
4) Do.

If it is determined in 111 that the load 2 of the own site a is not smaller than the load 0 of the task activation request destination, the subsequent processing is not executed.

On the other hand, the processor IC that has received the same task activation request communication via the communication device 2c updates the stored load 0 of the task activation request source site b to the sent value 2 (step 90■) or ( In step 902), it is determined that the own site C is not the task activation request destination site a, and (
In step 904), it is determined that the load 2 of the local site C is smaller than the negative σfO of the task activation request destination, so the subsequent processing is not executed.

At time 8, when a request to start task 9 is generated in the processor IC (at this point, as shown in FIG. 5, the load of own site C is 2, the stored load of site a is 0, 2) Similarly, task 9 is activated and executed by processor 1a, and at this time, the load status of site C stored in each site is updated from 0 to 2.

At time 9, even when a request to start task IO is generated in processor]a (at this point, as shown in FIG. 5, the load of own site a is 3, the stored load of site b is 2, 2) Similarly, if the load on site C is 2), task start request destination site identifier b1 task start request source site identifier a1 task start request source load 3, stored task start request destination site load 2, and task start request , broadcast communication to all sites as a task activation request communication (step 803).

The processor 2b that receives this task activation request communication via the communication device 2b sets the stored load of the site a to 0.
Update from to 3, start and execute task 10.

On the other hand, the processor 3b that received the same task activation request communication via the communication device 3b updates the stored load of site a from 0 to 3, and then updates the task activation request to which load 1 of own site c is sent. It is determined that the load is smaller than the previous load 2 (step 904), and the load reduction site identifier C and the load 1 of the own site are broadcasted to all sites as a load reduction notification communication (step 905). Processor la receives this load reduction notification communication via communication devices 2a and 2b.

(2) In b, the stored load of site C is updated from 2 to 1 (step 1001).

As a result, at time 10, when a request to start task 11 is generated on processor 1b, task 11 is actually started and executed on processor 1c, which has the lowest load, and at this time, the memory of each site is The load status of site b is updated from 2 to 3.

As a result of the above processing, the number of times the stored load status is updated due to the communication required to convey the load status to other sites is five times. Further, the time required to execute all tasks from task 1 to task 11 is 19.

By the way, in the conventional method of notifying each other when the load on each site changes every unit of time, the execution status of each task becomes as shown in Figure 4, which is the same as in this method, and all tasks are The time required for execution is 19, and the efficiency of the system using this method is the same, but the number of updates of the stored load status due to the communication required to convey the load status to other sites is 22. This results in a larger overhead than the method according to this embodiment.

In addition, with the conventional method of notifying each other when the load of each site changes every 3 units of time, the execution status of each task becomes as shown in Figure 6, and the actual load status and each site The change in the memorized load status of other sites is as shown in Figure 7, and the time required to execute all tasks at this time is 25, so the system is more efficient than the method according to this example. Deteriorate.

Furthermore, in the conventional method, the number of updates of the stored load state due to the communication required to convey the load state to other sites is 1211ii, so the overhead is larger than the method according to the present embodiment.

[Effects of the Invention] As described above, according to the load distribution control method of the present invention, the efficiency of the system can be improved by reducing the overhead in load distribution control processing.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a multi-site system according to the load distribution control method of the present invention, and FIG. 2 is a diagram showing the processing capacity of each processor in FIG. 1 in terms of the amount of work that can be processed per unit time. Figure 3 is a diagram showing the task activation request generation time, task activation request generating processor, and task workload corresponding to each task number when a task activation request occurs in each processor in Figure 1; Figure 1 shows the status of tasks started on each processor, and Figure 5 shows changes in the actual load in the multi-site system in Figure 1 and the load of other sites stored at each site. Figure 6 is a comparison example with the task status in Figure 4, Figure 7 is a diagram showing changes in the load status in Figure 6, and Figure 8 is when a task activation request is generated for each processor in Figure 1. 9 is a flowchart showing the operation at the time of receiving the task activation request communication in the multi-site system of FIG. 1, and FIG. 10 is a flow chart showing the operation at the time of receiving the task activation request communication in the multi-site system of FIG. 1. 3 is a flowchart showing the operation at the time. la, lb, lc--processor, 2a
, 2b. 2c...Communication device, a, b, c...Site.

Claims (2)

[Claims] (1) Having multiple sites to process multiple tasks, each site determines the current load status of its own site, transmits the load status to other sites, and remembers the load status of other sites. In a multi-site system that performs load distribution in a distributed manner, when a task activation request occurs, it is determined whether the load state of the own site has reached a predetermined load state limit, If the load state of the own site is smaller than the load state stored in the other site, or if the load state of the own site exceeds the load limit and is smaller than the load state stored in the other site, the task is started and executed at the local site, and if the load status of the local site exceeds the load limit and there is a load status stored at another site that is smaller than the load status of the local site, then , the site with the lowest load state among the stored load states of other sites is set as the task start request destination site, and the own site is set as the task start request source site, the task start request destination site identifier, the task start request source site Communication information consisting of an identifier, the load state of the task start request source, the stored load state of the task start request destination site, and the task start request is broadcasted to all sites as a task start request communication, and the task start request communication is When receiving the request, it updates the memorized load status of the task start requesting site to the sent load information, and if the local site is the task start requesting site, starts the task. A load distribution control method characterized in that it is executed. (2) Having multiple sites to process multiple tasks, each site determines the current load status of its own site, transmits the load status to other sites, and remembers the load status of other sites. In a multi-site system that performs load distribution in a distributed manner, when the own site recognizes the load status of the other site, the load status of the own site is smaller than the load status of the other site. In this case, the own site is set as a load reduction site, the load reduction site identifier and the load state of the load reduction site are broadcasted to all sites as a load reduction notification communication, and when the load reduction notification communication is received, the stored load A load distribution control method characterized by updating the load status of a reduced site to the transmitted load status.