JPH08153079A - Composite central processing unit system - Google Patents

Abstract

PURPOSE: To realize a load distribution so as to make a device in the lowest load state, a device whose load is comparatively low, or a device capable of responding most quickly, respond to a request by making each device in a composite central processing unit system measure its own load state. CONSTITUTION: In the composite central processing unit system, a central processing unit, a main storage unit and an input/output device are respectively provided with a reply controller equipped with a measuring means 14 measuring its own load value, a threshold value update means 17 consisting of an update means 15 updating a threshold value for managing the load state and a holding means 16 for holding the threshold value, a reply data holding/non-holding judging means 13 judging the holding of response data to a request at the time of receiving the request from another device, a comparing means 11 judging whether or not the request should be received based on the comparison between the load value and the threshold value, and a selection means 10 sending a reply/status output signal 53 to each device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of central processing units and input / output units connected to a common bus, each of which has a cache, and each unit measures its own load state to determine each unit. The present invention relates to a complex central processing unit system for autonomously load balancing controlling its own load state.

[0002]

2. Description of the Related Art In a conventional central processing unit, the load distribution for each unit is performed by a central processing unit that centrally controls the load, and a cache that holds a copy of data stored in a main storage unit. As a condition for determining whether or not to respond to a request from another device, whether the cache itself is the only cache holding the data, the data is updated, or the cache itself writes the data most recently. It controls whether or not to respond by using the information. For example, in the complex central processing unit system 1 shown in FIG.
Issue a request for the address A to the common bus and another central processing unit 100 holds the data of the address A in the cache, 1. When the data of the address A differs between the cache of the central processing unit 100 and the main memory 200, another central processing unit 100 which is the holder of the data responds to the request.

2. When the data at the address A is the same in the cache and in the main storage device 200, the main storage device 200 itself responds because the holder of the data is absent.

In the latter case, both the main memory 200 and the central processing unit 100 having a cache hold the data of the address A, so that both can respond to the request, but the central processing unit 100 and main memory 2
00 is the same, the main memory device 200 is always
Will respond.

[0005]

The above-described conventional method of responding to a request responds because the device holding the requested data responds regardless of the load state of each device. Devices tend to concentrate on a particular device. Therefore, in the state where the number of central processing units increases and the load increases, requests concentrate on a small number of devices, delaying the timing of responding, and prolonging the access time. Therefore, as the number of central processing units increases, it is likely that the performance of each central processing unit cannot be exhibited, and the number of central processing units connected to the common bus is limited.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a means for measuring the load state of each device of a complex central processing unit system, and when a plurality of devices can respond,
Distribute the load by responding to the device with the lowest load, the device with a relatively low load, or the device that can respond the fastest, and perform load distribution that does not cause load concentration that causes performance degradation even in a high load environment. It is to be realized.

Therefore, in the present invention, a plurality of central processing units, main storage units, and input / output units are connected to a common bus, and each of the central processing unit and the input / output units has a cache for the storage units. In the complex central processing unit system, each of the central processing unit, the main storage unit, and the input / output unit has a load value of its own load state measured by itself and a threshold value for determining the load state. When holding the request and accepting the request from the device other than itself, the request can be accepted based on the determination result of whether or not the response data to the request is held, and the load value and the threshold value. The reply control device, which sends the determination result of whether or not there is, to each of the devices connected to the common bus, responds to the request. Reply data holding / non-holding judging means for judging whether or not the data is held in the cache, and load measuring means for measuring the load value of the load state of each of the devices based on the number of waiting requests for each of the devices. And a threshold initialization means for initializing the threshold value for determining whether or not to respond to the request of the reply control device of the other device, holding the threshold value, and adapting the threshold value to a load state Threshold updating means for updating to a threshold, and comparing means for outputting the result of comparing the threshold and the load value notified from another reply control device and the determination result of holding / not holding the response data as a reply status output signal. , Accepts the reply data holding / non-holding judgment result of the other reply control device or the load value, and holds it by itself Select whether to respond to the request as compared with the load value, characterized in that it comprises a selection means for access requests to the cache or main memory.

[0008]

Next, the present invention will be described with reference to the drawings.

Referring to FIG. 1 showing the configuration of an embodiment of the present invention, the reply control device 5 receives a request signal 52 from another device through the common bus 4 and sends response data corresponding to the request signal 52. Own cache 6
Hold reply data to determine whether or not
In the non-holding determination means 13, the cache of the central processing unit (not shown), the main storage device (not shown), and the input / output device (not shown)
A load measuring unit 14 that measures a load value indicating each load state, and a request signal 5 of another reply control device 5
2, a threshold value initialization means 12 for initializing a threshold value for a load state for determining whether or not it responds, a threshold value holding means 16 and an updating means 15 for updating the threshold value to a threshold value adapted to the load state. The threshold updating means 17 having the same, the comparing means for outputting the result of comparing the held threshold value and the load value from the reply control device 5 of another device (not shown) and the result of holding / not holding the response data as a reply status. 11 and another reply control device 5 not shown
An access request 5 to the cache 6 or the main storage unit 9 of its own from the reply status input signal 54 and the reply status output signal 53 of its own sent from
The selection means 10 which selects 0 is provided.

Further, referring to FIG. 2 exemplifying a composite central processing unit system 1 including devices each having a reply control device 5, the composite central processing unit system 1 comprises:
A plurality of central processing units 100 and a plurality of main storage devices 2
00 and a plurality of input / output devices 300 are connected to the common bus 4.

Further, referring to FIG. 3A exemplifying the reply control device 5 provided in the central processing unit 100, the central processing unit 100 receives a plurality of arithmetic units 800 and requests from the respective arithmetic units 800. The request accepting unit 7, the cache 6 that holds a part of the data in the main memory 9 and returns the response data to the request accepting unit 7 and the access request 50 through the reply signal line 51, and the request signal 5 that accepts through the common bus 4.
2 and a reply status output signal 53 that responds to the load status and a reply status input signal 54 that sends the load status of another device, and a reply control device 5 that sends an access request 50 to the cache 6. Prepare

Referring to FIG. 3B illustrating the reply device 5 provided in the main memory device 200, the main memory device 2
00 is a request signal 5 received through the common bus 4.
2 and a reply status output signal 53 that responds to the load status and a reply status input signal 54 that sends the load status of another device, and a reply control device 5 that sends an access request 50 to the main storage unit 9. , The main memory 9 and the reply signal 51 output from the main memory 9.
And

Referring to FIG. 3C, which illustrates the reply control device 5 provided in the input / output device 300, the input / output device 300 includes a plurality of channels 900 and channels 9.
Request accepting unit 7 that accepts a request from 00, a cache 6 that holds a part of the data in main memory 9 and returns response data to request accepting unit 7 and access request 50 through reply signal 51, and accepts through common bus 4. Request signal line 52 for responding and reply status output signal 53 for responding to the load condition
And a reply control device 5 that sends and receives a reply status input signal 54 that sends the load status of another device, and sends an access request 50 to the cache 6.

Further, FIG. 4 exemplifying the load measuring means 14
Referring to (a), the load measuring means 14 determines that the cache 6
Alternatively, the number of waiting requests in the request buffer 19 for registering a request for the main storage unit 9 is measured.
Referring to FIG. 5A exemplifying the reply status signal 53, the reply status output signal 53 is a signal for outputting whether or not it can respond based on the judgment of the reply device itself. Further, FIG. 6 exemplifying the selection means 10
Referring to (a), the selection means 10 itself determines whether or not to respond by the LRU based on the response history storage 28 for the request, and designates the corresponding device. Further, referring to FIG. 7C exemplifying the updating means 15 and the threshold updating means 17 having the threshold value 16, the own threshold value 16 is updated by its own reply / status output signal 53, and a new adaptation is made to adapt to the load condition. A different threshold is set in the holding means 16.

Next, the operation of this embodiment will be described with reference to the flow chart of FIG. 8. In the processing of the request signal 52 (step 400), the reply control device 5 first requests from another reply control device 5 through the common bus 4. The signal 52 is accepted (step 401). The reply control device 5
The reply data holding / non-holding judging means 13 of itself judges whether or not the reply is possible depending on whether or not the reply data corresponding to the request is held by itself. When the response data is not held (NO in step 401), the process ends without responding (step 413). When the response data is held (YES in step 402), the load measuring unit 14 illustrated in FIG. 4A and the load of the own device which is determined from the number of waiting requests for the own cache and the threshold 16
Is compared by the comparison means 11 (step 403),
Result reply / status output signal 53 is sent to common bus 4
To each device through (step 404).

Next, the selection means 10 illustrated in FIG. 6 (a).
Receives a reply status input signal 54 from another reply control device 5 (step 405), selects a device responding to the reply status input signal 54,
When the only device that can respond is its own device (step 40
6), the access request 50 is issued to the cache 6 or the main storage unit 9, and the reply signal 51 illustrated in FIG. 3 is sent from the cache 6 or the main storage unit 9 to each device through the common bus 4 (step 410). ). When the device that can respond is not only the device itself (step 40
(NO of 6), when the device having a device load lower than the threshold value 16 is the only device among the devices to which the selecting means 10 can respond (YES in step 407), an access request is made to the cache 6 or the main storage unit 9. 50, and the reply signal 51 is sent from the cache 6 or the main memory 9 to each device through the common bus 4 (step 410).

Furthermore, when the device which can respond is not only its own device (NO in step 407), the selecting means 10 stores the response history storage 28 which the selecting means 10 stores from the devices which can respond and whose load state is equal to or less than the threshold value 16 itself. When the own device is the device that responded to the most in the past by (YE of step 408)
S), the access request 50 is issued to the cache 6 or the main memory 9, and the reply signal 51 is sent from the cache 6 or the main memory 9 to each device through the common bus 4 (step 410).

Furthermore, if the self-device is the device that responded to the oldest among the devices that can respond (Y in step 409).
ES), the access request 50 to the cache 6 or the main storage unit 9, and the cache 6 or the main storage unit 9
Sends the reply signal 51 from each device to each device through the common bus 4 (step 410). If the own device is not the device that responded the earliest among the devices that can respond (NO in step 409), the selection unit 10 determines the responding device from the response history storage 28 recorded in itself, and sets the threshold value. 1
7 (c) illustrating 6 and the updating means 15, the response order determining LRU is updated (step 411). When the own device executes the response, the selecting means 10 causes the updating means 15 to increase the threshold value according to the data length of the response data. If the device itself holds the response data but does not respond, the threshold is decreased (step 41
2) Then, the process for the request signal 52 is completed (step 413).

Next, in the load measuring means 14 of this embodiment,
Modifications illustrated in FIGS. 4B, 4C, and 4D can be made. According to FIG. 4B, the cache 6
Alternatively, each time the main memory 9 is accessed, a fixed value 21
Can be set in the counter 29 through the adding means 22 and the counter can be subtracted by a clock to express the load value as time passes. Further, according to FIG. 4C, the temperature change due to the read / write operation on the surface of the memory package 25 is measured by the temperature sensor 24, converted into a digital value by the AC converter 26, and converted into the load value of the main storage unit 9. The correction value can be obtained by the correction means 27. Further, according to FIG. 7D, one bit is input to the shift register 18 each time the cache 6 or the main storage unit 9 is accessed, the shift is performed by a clock, and the number of accesses is counted when N clocks have elapsed, It can be a load value.

Further, the reply status signal 53 output from the reply control device 5 of this embodiment is shown in FIG.
Modifications illustrated in (b), FIG. 5 (c), and FIG. 5 (d) can be made. According to FIG. 5B, the reply status signal 53 can be output as load information of binary code of n-bit parallel. According to FIG. 5C, load information can be output from the reply status signal 53 through the N signal lines of the time division signal. According to FIG. 5 (d),
It is possible to output load information represented by the time until the reply status signal 53 is responded.

Further, the selecting means 10 of this embodiment has the configuration shown in FIG.
Modifications illustrated in (b), FIG. 6 (c), FIG. 6 (d), and FIG. 6 (e) can be made. According to FIG. 6B, from the response history storage 29 stored in the selecting means 10, the device that has sent a response in the latest past and the reply status input signal 54 of another device, the device that responded in the latest past. The following devices can respond: According to FIG. 6 (c), the selection means 10 uses the response history storage 30 acquired from the bus arbitration means (not shown) of the common bus 4 to determine the next common bus 4.
The device which acquires the common bus 4 earliest can be made to respond from the device which acquires the common bus 4 and the reply status input signal 54 of the other device. According to FIG. 6D, the device having the lowest load value can be made to respond from the reply status input signal 54 of another device. According to FIG. 6E, it is possible to make the device that responds the fastest to the reply status input signal 54 respond.

Further, the threshold 16 and the updating means 1 of this embodiment
7 (a), 7 (b),
Modifications illustrated in FIGS. 7D and 7E can be made. According to FIG. 7A, the initial value of the threshold value holding means 16 can be set by the initialization means 12. Figure 7
According to (b), the threshold 16 can be set by the threshold setting command of the arithmetic processing means 800. According to FIG. 7D, the threshold value 16 can be updated by the load value of the reply status input signal 54 of another device and the updating means 15. According to FIG. 7E, the threshold 16 can be updated with the load value of the reply status input signal 54 of another device and the threshold correction value 32.

[0023]

As described above, according to the present invention, the reply control device is provided in each of the central processing unit, the main storage unit and the input / output unit connected to the common bus of the complex central processing unit system. The load state of each device is measured, and the load value is used to determine whether each device autonomously responds to the request. Therefore, it is possible to prevent the load from being concentrated on a specific device.

Further, according to the present invention, the threshold value of the load value for judging whether or not each device responds to the request can be changed in accordance with the load state, so that it can be adapted to the load fluctuation of the entire complex central processing unit system. Load distribution can be controlled.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram illustrating a composite central processing unit system including respective devices including the reply control device of FIG.

3A, 3B, and 3C are interfaces of a central processing unit and a reply control unit, a main memory unit and a reply control unit, an input / output unit and a reply unit.
It is a figure which illustrates each.

FIG. 4 is a diagram (a), a diagram (b), a diagram (c), a diagram (d), and a diagram (e), in which the load measurement unit of FIG. In the figure, the load value is measured by the access frequency to the main memory or the cache, the load value is measured by the power consumption of the operation, and the load value is measured by the number of accesses to the main memory or the cache. is there.

5A, 5B, 5C, and 5D are response diagrams to the reply status signal of FIG. It is a figure which illustrates each application of the load value which shows a state, the time division signal of load information, and the time until response of load information.

6A, 6B, 6C, 6E, 6E, 6E, 6E, 6E, 6E, 6E, and 6E are the following devices that select and respond by LRU to the selecting means of FIG. Choose the earliest device to respond,
It is a figure which illustrates application of the selection of the device with the lightest load, and the selection of the device which arrived the earliest response, respectively.

7A, 7B, 7C, 7D, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, 7E, and 9E , The threshold setting by the threshold setting command, the threshold setting updated by its own load status, the threshold setting updated by the load status of another device, the load status of another device, and the correction value determined by itself It is a figure which illustrates application of the setting of the updated threshold value, respectively.

8 is a flowchart showing the operation of the embodiment of FIG.

[Explanation of symbols]

 1 Complex Central Processing Unit System 5 Reply Control Device 6 Cache 9 Main Storage Unit 10 Selection Means 11 Comparison Means 12 Threshold Initialization Means 13 Reply Data Hold / Non-Hold Judgment Means 14 Load Measuring Means 15 Update Means 16 Threshold Hold Means 17 Threshold Updates Means 50 Access request 51 Reply signal 52 Request signal 53 Reply status output signal 54 Reply status input signal 100 Central processing unit 200 Main storage unit 300 Input / output unit

Claims (2)

[Claims] 1. A composite central processing system comprising a plurality of central processing units, a main storage unit, and an input / output unit connected to a common bus, each of the central processing unit and the input / output unit having a cache for the storage unit. In the device system, each of the central processing unit, the main storage device, and the input / output device holds a load value of its own load state measured by itself and a threshold value for determining the load state, and When accepting a request from the device, determining whether the request can be accepted based on the result of determination as to whether or not the response data for the request is held, and the comparison between the load value and the threshold. A reply control device that sends the result and the device to each of the devices connected to the common bus, and each of the devices controls its own load state. Composite central processor system to symptoms. 2. The reply control device comprises reply data holding / non-holding judging means for judging whether or not the response data corresponding to the request is held in a cache, and the number of waiting requests for each device. Load measurement means for measuring the load value of each device based on the load condition, and threshold initialization for initializing the threshold for determining whether or not to respond to the request of the reply control device of the other device Means, holding the threshold value, a threshold value updating means for updating the threshold value to a threshold value adapted to the load state, a result of comparing the load value notified from the other threshold value with the reply control device, and holding the response data / Comparison means for outputting a determination result of non-holding as a reply status output signal, and the reply data of another reply control device. A selection means for accepting the determination result of holding / non-holding or the load value, selecting whether to respond to the request by comparing with the load value held by itself, and making an access request to the cache or the main storage device. The reply control device according to claim 1, further comprising: