JPH07334449A - Input/output load distributing system - Google Patents

Abstract

PURPOSE:To prevent system throughput and input/output (I/P) response from being degraded even when load is concentrated into a specific I/O controller. CONSTITUTION:This I/O load distributing system is provided with an I/O route discriminating means 12 for discriminating all I/O routes through I/O controllers 22a, 22b for peripheral devices 25a to 25c, load measuring means 10a, 10b for measuring the load of the controllers 22a, 22b corresponding to respective I/O routes discriminated by the means 12, a load statistic information storing means 11 for storing the load on the controllers 22a, 22b as statistic information based upon the load values measured by the means 10a, 10b, an information providing means 15 for determining respective I/O routes for executing I/O requests to the devices 25a to 25c, and a low load route selecting means 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input / output load balancing system in a computer system capable of connecting a plurality of input / output control devices to peripheral devices.

[0002]

2. Description of the Related Art Generally, as a form of a computer system capable of connecting a plurality of input / output control devices to a peripheral device, firstly, a form in which a plurality of peripheral devices are connected to the input / output control device and secondly in one peripheral device are connected. The configuration is such that a plurality of input / output control devices are connected.

In the case of the second mode, it is possible to have a plurality of input / output paths for one peripheral device.
This is an effective configuration for realizing a fault tolerant system.

By the way, the configuration of each peripheral device and the input / output control device that handles the same device is usually fixedly determined when the system is started. Further, in the configuration having the second mode in which a plurality of input / output control devices are connected to one peripheral device, it is possible to have a plurality of input / output paths, but the input / output path to be used is the system startup. It is fixedly decided at times.

Then, in the standard time, only one decided input / output path is used, and the other paths are used as alternative paths when a failure occurs, or input / output is explicitly input from the outside by a command or the like. The route may be changed.

Therefore, when I / O requests are concentrated on a peripheral device handled by a certain I / O controller during system operation, it goes without saying that a plurality of peripheral devices are connected to one I / O device. Even in the case where a plurality of input / output devices are connected to one peripheral device, there is a problem that the route cannot be changed and the load is concentrated on one input / output control device, which lowers the system throughput.

Further, since the load is concentrated on the input / output control device, the input / output response required for the input / output response such as transaction processing is uniformly lowered.

[0008]

As described above, in the conventional computer system in which a plurality of input / output control devices for peripheral devices can be connected, the input / output paths corresponding to the configurations of the input / output control device and the peripheral devices are fixedly determined. Therefore, if the input / output requests concentrate on the peripheral devices, there is a problem that the system throughput and the input / output response decrease.

The present invention has been made in consideration of the above circumstances, and an input / output load balancing system in which the system throughput and the input / output response are not deteriorated even if the load is concentrated on a specific input / output control device. The purpose is to provide.

[0010]

According to the present invention, in a computer system in which a plurality of input / output control devices for a peripheral device can be connected to configure a plurality of input / output paths, all input / output devices for the peripheral device are connected. Input / output path identifying means for identifying the output path, load measuring means for measuring the load of the input / output control device corresponding to each input / output path identified by the input / output path identifying means, and measured by the load measuring means. Load statistical information storage means for storing the load of the input / output control device as statistical information based on the load, and an input / output request to the peripheral device based on the statistical information stored by the load statistical information storage means. And an input / output path determining means for determining an input / output path for performing

Further, the input / output path determining means sets a threshold value specified when an input / output request is made to a peripheral device and a load status of the input / output control device indicated by the statistical information accumulated by the load statistical information accumulating means. An information providing unit that determines whether the input / output path needs to be changed based on the result of the comparison, and the information providing unit determines that the input / output path needs to be changed when the load condition exceeds the threshold value. And a low load route selecting means for selecting a low load route from a plurality of input / output routes, and an input / output request is made via the input / output route selected by the low load route selecting means. Characterize.

Further, when an input / output request is issued to the peripheral device, a deadline adding means for adding a limit value (deadline) that allows a delay in processing response to the input / output request is further provided. The information providing means determines whether or not it is necessary to change the input / output path based on the limit value (deadline) added by the deadline adding means, and the low load path selecting means is the information providing means. When it is determined that the input / output path needs to be changed by, the input / output path for the input / output request is selected.

Further, when it is determined by the information providing means that the input / output request to which the deadline is added does not comply with the deadline, the low-load path selecting means makes the subsequent input / output request a deadline. I / O requests to which deadlines are assigned are executed on low-load I / O paths, and other I / O requests to which deadlines are not assigned are executed on high-load I / O paths until It is characterized in that the input / output path is selected as described above.

[0014]

With such a configuration, in a computer system to which a plurality of input / output control devices for peripheral devices can be connected, when performing input / output processing for peripheral devices,
An I / O path with a light load is selected from a plurality of I / O paths, and an I / O path for requesting an I / O is dynamically changed. Therefore, even if the load on the input / output control device to which the peripheral device is connected is concentrated, the load is distributed by changing the input / output path, and it is possible to avoid a decrease in the throughput of the entire system.

Input / output is performed based on load accumulation information (load based on the number of input / output requests to peripheral devices, processing time, etc.) accumulated for each input / output control device, and a predetermined threshold value given from the outside. The need to change the route is determined.
Therefore, an appropriate input / output path is changed according to the operating status of the system.

For input / output processing for which there is a demand for processing response time to the input / output request, a target value (deadline) that may delay the processing is added to the input / output request so that the target input can be performed. Based on the statistical information of the response time of the latest input / output request of the output control device, the input / output path that can achieve the request is selected and the input / output request is made.

At this time, the input / output request to which the limit value (deadline) is added is prioritized as having a limited processing response time so that the response time can be shortened by using the low-load input / output path. For I / O requests that are not accompanied by a limit value (deadline) for the time being,
An input / output path with a higher load than the input / output path selected with priority is selected.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the input / output load balancing function in the computer system according to this embodiment.

As shown in FIG. 1, the input / output load balancing function of the present embodiment has a load measuring means 10, a load statistical information accumulating means 11, an input / output path identifying means 12, a deadline load means 13, and an input / output path. Determining means 14 (information providing means 1
5, low load route selection means 16).

The load measuring means 10 is means for measuring the load of the input / output control device provided in the computer system, and the load statistical information accumulating means 11 stores information indicating the result of measuring the load of the input / output control device. It will be returned.
If there are a plurality of input / output control devices provided in the system, the load measuring means 10 measures the load on its own device in each input / output control device. The load on the input / output control device includes the number of input / output requests to various peripheral devices (external storage device, etc.) connected to the input / output control device and the time required to complete the input / output with the peripheral device.

The load statistical information accumulating means 11 is a means for sequentially accumulating the load of the input / output control device as statistical information with the passage of time.
The load of the input / output control device obtained by the load measuring means 10 is accumulated as load statistical information. The load statistical information storage means 11 stores the load statistical information for each input / output control device.

The input / output path identification means 12 is means for identifying information about all the input / output paths to / from each peripheral device passing through each input control device, and when input / output processing requests are made to the peripheral device, input / output of each peripheral device is performed. It is possible to extract the route information regarding the output route and the load statistical information regarding each input / output control device.

The deadline adding means 13 adds information indicating a limit value (deadline) that allows the delay of the processing response to the input / output path to be used, to the input / output request from the input / output request source to the peripheral device. It is a means for setting a limit value that may be delayed in processing response when performing input / output processing with a peripheral device in response to an input / output request.

The input / output path determining means 14 determines an input / output path for making an input / output request to the peripheral device based on the load statistical information accumulated by the load statistical information accumulating means 11. The input / output path determining means 14 includes an information providing means 15 and a low load path selecting means 16.

The information providing means 15 has a threshold value given at the time of an input / output request from the outside with respect to the load statistical information of the input / output control device extracted by the input / output path identifying means 12,
A deadline added to the input / output request by the deadline adding means 13 is received and stored, and the low load route selecting means 16 determines the necessity of changing the input / output route based on the information and selects a low load route. To provide various information.

The low load route selecting means 16 uses the various information provided from the information providing means 15 to perform the input / output processing when the information providing means 15 determines that the input / output path needs to be changed. Select the input / output path to be used for.

FIG. 2 is a block diagram showing the configuration of a computer system according to an embodiment of the present invention equipped with the load balancing function shown in FIG. As shown in FIG. 2, in the computer system of this embodiment, a processor 19 and a memory 20 are connected to a plurality of input / output control devices 22a and 22b via a system bus 21.

The input / output control device 22a includes an input / output bus 23.
a via a plurality of bus interfaces 24a, 24
The input / output control device 22b is connected to the plurality of bus interfaces 24 via the input / output bus 23b.
It is connected to b, 24d, and 24f. Each of the bus interfaces 24a to 24f has an input / output control device 22.
It is managed by a and 22b.

In addition, the bus interfaces 24a and 24b
A peripheral device 25a is connected to the bus interface 2
A peripheral device 25b is connected to 4c and 24d, and a peripheral device 25c is connected to the bus interfaces 24e and 24f. Further, the input / output control device 22a includes a bus 2
Another peripheral device 25d is connected via 3c. The input / output control device 22a is provided with a load measuring means 10a, and the input / output control device 22b is provided with a load measuring means 10b.
Shall be provided.

In the configuration shown in FIG. 2, for example, the input / output path for the peripheral device 25a is the input / output control device 22a →
I / O bus 23a → bus interface 24a → peripheral device 25a and I / O controller 22b → I / O bus 23b
There are two types: → bus interface 24b → peripheral device 25a. Similarly, the other peripheral devices 45b and 45c also have two input / output paths. In the computer system of this embodiment, among the plurality of input / output paths, the peripheral devices 25a, 25b, 2 are usually used when the system is constructed.
It is assumed that the master path for 5c (in this embodiment, either one of the input / output paths) is set and used. The input / output path used is changed according to the change in the load on the input / output control devices 22a and 22b.

The load statistical information accumulating means 11, the input / output path identifying means 12, the deadline load means 13, the information providing means 15, and the low load path selecting means 16 shown in FIG. 1 are realized on the processor 19. Also, in the memory 20,
Various information (peripheral device information 30, input / output control device management information 32, deadline information 34) and the like handled by each unit shown in FIG. 1 are stored. The deadline information 34 is
It is stored when given to the information providing means 15 at the time of input / output request.

The peripheral device information 30 and the input / output control device management information 32 stored in the memory 20 will now be described with reference to the data structure shown in FIG. The peripheral device position information 30 includes route information regarding each peripheral device 25a, 25b, 25c connected to the input / output control devices 22a, 22b. For example, the peripheral device information 30a of the peripheral device 25a includes route information 31 about two routes.
a is prepared. Route information 31b and 31c are similarly prepared for peripheral device information 30b and 30c corresponding to the other peripheral devices 25b and 25c, respectively.
The route information included in the peripheral device position information 30 is determined when the system is constructed and stored in the memory 20.

The input / output control device management information 32 stores the load on each input / output control device 22a, 22b as load statistical information. Load statistical information 33a is prepared in the input / output control device management information 32a of the input / output control device 22a, and the input / output control device management information 3 of the input / output control device 22b is prepared.
Load statistical information 33b is prepared in 2b.

The peripheral device information 30a, 30b, 30c and the input / output control device management information 32a, 32b, 32c are related by the route information 31a, 31b, 31c existing in the peripheral device information 30a, 30b, 30c. .
The route information 31a, 31b, 31c is managed by the input / output route identification means 12 that identifies all the input / output routes to the peripheral device. In addition, the input / output control device 22a,
The load statistical information 33a, 33b, 33c of 22b is accumulated (updated) over time by the load statistical information accumulating unit 11 that accumulates the load of the input / output control devices 22a, 22b as load statistical information.

For example, the load statistical information is the load (the number of input / output requests to various peripheral devices (external storage devices, etc.) connected to the input / output control device, the time required to complete the input / output with the peripheral device, etc.). Shall be represented by the temporal accumulation of.

Next, the operation of this embodiment will be described with reference to the flow chart shown in FIG. In this embodiment, the load balancing process, that is, the operation of selecting a low-load route from the two input / output routes will be described by taking as an example a case where an input / output request is made to the peripheral device 25a. In addition,
In the peripheral device 25a, the input / output path passing through the input / output control device 22a is set as the master path.

First, the information providing means 15 operating on the processor 19 is assigned a deadline by the deadline adding means 13 to the input / output request issued from the input / output request source, or is input from the outside. It is checked whether a threshold value for the load of the output control device is set (step S1). The processing when the deadline is loaded on the input / output request will be described later.

After that, the information providing means 15 receives the load statistical information 33a for the input / output control information 22a stored in the memory 20 by the load statistical information accumulating means 11 from the input / output path identifying means 12, and the load statistical information 33.
A is compared with the deadline / threshold value to determine whether or not the input / output path needs to be changed (step S2).

That is, the specified input / output path of the peripheral device information 30 (here, the input / output control device 22 which is the master path).
Whether or not the load statistical information 33a of the input / output control device 22a of the input / output control device management information 32, which is referred to by the route information 30a regarding the input / output route via (a), exceeds the set deadline / threshold value. Determine whether.

As a result of this comparison, when it is determined that the input / output path does not need to be changed, the input / output request is issued to the peripheral device 25a as it is via the input / output path at this time (step S5). .

For example, if the load statistical information 33a of the input / output control device 22a indicates the load x and the threshold i is set, and if there is a relation of "x <= i", the input / output path is changed. Instead, the I / O request is issued through the I / O control device 22a as it is.

On the other hand, when it is determined in step S2 that the input / output path needs to be changed, that is, "x>"
If there is a relation of "i", the low load route selecting means 16
Are input / output control devices 22a, 22 on all input / output paths.
It is activated to execute the route selection processing based on the load statistical information of b.

The low load route selecting means 16 provides the load statistic information of the input / output control devices 22a and 22b on all the input / output routes in the input / output control device management information 32 stored in the memory 20. It is received via the means 15 (step S3).

The low load route selecting means 16 carries out step S3.
The statistical load information 32a and 32b corresponding to the input / output control devices 22a and 22b obtained in step S1 are compared with each other, and an optimum route with a small load is selected from a plurality of input / output routes according to the comparison result.

That is, the low load route selecting means 16 checks the load statistical information (assumed to be the load y) of the input / output control device 42b and compares it with the load statistical information 33a of the input / output control device 22a currently used. .

As a result, if there is a relation of "x <= y", the input / output control device 22a currently used as it is.
I / O route via On the other hand, for example, a peripheral device 25d connected to the input / output control device 22a
When the relation of “x> y” is satisfied because the number of input / output requests to the input device has increased, the low load route selection unit 16 selects the input / output route via the input / output control device 22b having a small load.

When the input / output path to be used is selected by the low load path selecting means 16 in this way, an input / output request is issued to the peripheral device 25a via the selected input / output path (step S5).

When a completion response is returned to the issuance of this input / output request, the load measuring means 10a of the input / output control device 22a stores the load information (response time) for the input / output control device 22a in the load statistical information storage means. Output to 11.

The load statistical information accumulating means 11 updates the load statistical information of the input / output control device management information 32 of the memory 20 by using the load information for the input / output control device 22a in use returned with the completion response ( Step S6).

In this way, the above-described load balancing process for the peripheral device 25a is also performed for the peripheral devices 25b and 25c, and an input / output path with a light load is used. Therefore, the load of the input / output control devices 22a and 22b is dispersed in the entire system, and it is possible to prevent a decrease in throughput due to the concentration of the load on one input / output device.

Next, when the input / output request source issues an input / output request, the deadline load means 13 assigns a limited value (deadline) that may delay the processing response to the input / output request. It shows the case.

In the load measuring means 10 for measuring the load of the input / output control device, the actual response time of each input / output request is also measured as one component of the load. The load statistical information accumulating means 11 accumulates the response time of each input / output request to the input / output control device measured by the load measuring means 10 as load statistical information.

When the deadline load means 13 issues an input / output request to which a deadline is assigned,
The information providing unit 15 extracts the load statistical information of the response time of the latest input / output request of the target input / output control device and compares it with the assigned deadline.

Here, when the deadline is not observed, that is, when the time required for processing response exceeds the deadline, the low load route selecting means 16 is activated.
The low load route selection means 16 is based on the load statistical information,
Select the route with the lowest load among multiple I / O routes.
The I / O request is issued to the peripheral device via the selected I / O path.

When the input / output request to which the deadline is assigned does not comply with the deadline, when the input / output request to which the deadline is not assigned is issued, the low load route selecting means 16 determines that the deadline is Select a higher load I / O path so that the assigned I / O requests can preferentially use the lighter load I / O path.
The low load route selection means 16 selects a high load input / output route for an input / output request to which a deadline is not assigned until the input / output request to which the deadline is assigned can comply with the deadline. .

As a result, the load of the input / output path used by the input / output request to which the deadline is assigned is adjusted,
The response time can be maintained. In this way, the input / output requests to the peripheral devices 25a, 25b, 25c are dynamically selected and output from the plurality of input / output paths, respectively. Therefore, for example, even when the input / output requests are concentrated on the peripheral device handled by a certain input / output control device during system operation, the input / output requests are sent via the low load input / output path. , System throughput is not reduced.

Regarding an input / output request for which an input / output response such as a transaction process is required, the response to the input / output request may be delayed according to the deadline assigned to the input / output request. Since the input / output path from which the input / output response is obtained is selected, the required response can be maintained.

In the above embodiment, the load statistical information is described as being represented by the temporal accumulation of the load on the input / output control device, but the load on each input / output control device is relative, for example, by the average load. As long as they can be compared, the form is not particularly limited.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a computer system according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the flow of load distribution processing in this embodiment.

FIG. 3 is a block diagram of a structure for managing a load status according to the present invention.

FIG. 4 is a configuration diagram showing an embodiment of the present invention.

[Explanation of symbols]

10 ... Load measuring means, 11 ... Load statistical information accumulating means, 1
2 ... I / O path identifying means, 13 ... Deadline adding means, 14 ... I / O path determining means, 15 ... Information providing means,
16 ... Low load route selecting means, 20 ... Memory, 22a, 2
2b ... I / O controller, 23a, 23b, 23c ... I / O bus, 24a, 24b, 24c, 24d, 24e, 2
4f ... Bus interface, 25a, 25b, 25c,
25d ... Peripheral device, 30a, 30b, 30c ... Peripheral device information, 31a, 31b, 31c ... Input / output path information, 32
a, 32b, 32c ... Input / output control device management information, 33
a, 33b, 33c ... Load statistical information.

Claims (4)

[Claims] 1. A computer system capable of configuring a plurality of input / output paths by connecting a plurality of input / output control apparatuses for peripheral devices, and an input / output path for identifying all input / output paths via the input / output control apparatus for peripheral devices. Identification means, load measurement means for measuring the load of the input / output control device corresponding to each input / output path identified by the input / output path identification means, based on the load measured by the load measurement means,
Load statistical information storage means for storing the load of the input / output control device as statistical information; and an input / output path for making an input / output request to the peripheral device based on the statistical information stored by the load statistical information storage means. An input / output load balancing method comprising: an input / output path determining means for determining. 2. The input / output path determining means includes a threshold value specified when an input / output request is made to a peripheral device, and a load status of the input / output control device indicated by the statistical information accumulated by the load statistical information accumulating means. Based on the result of the comparison, the information providing unit that determines whether the input / output path needs to be changed, and the information providing unit determines that the input / output path needs to be changed when the load status exceeds the threshold value. In this case, a low load route selecting means for selecting a low load route from a plurality of input / output routes, and an input / output request is made via the input / output route selected by the low load route selecting means. The input / output load balancing method according to claim 1, wherein 3. A deadline adding means for adding a limit value (deadline) that allows a delay in processing response to the input / output request when the input / output request is issued to the peripheral device, The information providing means determines whether or not the input / output path needs to be changed based on the limit value (deadline) added by the deadline adding means, and the low load path selecting means is the information providing means. 3. The I / O load balancing method according to claim 2, wherein the I / O path for the I / O request is selected when it is determined that the I / O path needs to be changed. 4. The low-load route selecting means, when the information providing means determines that an input / output request to which a deadline is added does not comply with the deadline, the subsequent input / output request is a deadline. I / O requests to which deadlines are assigned are executed on low-load I / O paths, and other I / O requests to which deadlines are not assigned are executed on high-load I / O paths until The input / output load balancing method according to claim 3, wherein the input / output path is selected as described above.