JPH049349B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an instruction queue management processing method, in particular, a method in which a central processing unit writes input/output instructions on a subchannel control word corresponding to a device, and performs processing in a channel. The present invention relates to an instruction queue management processing method in a data processing system that relies on a processor.

(B) Summary of Disclosure In a data processing system, a central processing unit writes input/output instructions on a subchannel control word corresponding to a device, and a channel processor reads the input/output instructions on the subchannel control word and proceeds with processing. A group control word list queue is created for a group that has input/output commands waiting for a control table divided into two groups, and when one of the groups is extracted from the list queue, the first or last group is to be extracted. By performing the extraction only when the input/output commands are longer than the input/output commands, the channel processor can efficiently execute input/output commands.

(C) Prior Art and Problems to be Solved by the Invention Recently, data processing systems constructed under the concept of extended architecture are being considered. Then, as a processing mode corresponding to the input/output command, the central processing unit writes the input/output command on the subchannel control word that exists for each input/output device, and the channel processor reads the input/output command on the subchannel control word. It is being done to execute the process using .

In the case of such a system, processing may be concentrated on a path leading to a specific input/output device. Taking the drawings corresponding to the present invention described later as an example, each input/output device 1 to 4 is Despite having paths accessed by four channels, channels 9 to 12, respectively, a situation may arise in which, for example, only channel 9 becomes busy, while the other channels 10 to 12 remain idle.

To solve this problem, consideration has been given to dividing paths leading to input/output devices into groups and rotating processing between each group to efficiently execute input/output commands.

However, even in this case, the following new problem is raised. That is, if the channel processor were to check the existence of input/output instructions even for groups for which no input/output instructions are currently written, the overhead for this would increase. Therefore, the group control word list for the group in which the input/output command currently exists is
It is considered that a queue is prepared and the channel processor follows the list queue for access. However, even in this case, if you try to immediately cut out a group from the list/queue when there are no input/output commands for one group at a certain point in time, this process also results in considerable overhead.

(D) Means for Solving the Problems The present invention solves the above-mentioned problems by preparing the group control word list queue and, for example, regarding the group connected to the end of the list queue. The group is cut out from the list/queue when it is in the state where it can be cut out. Therefore, the instruction queue management processing method of the present invention includes at least a storage device, one or more channel processors, and a plurality of input/output devices, and a subchannel control command that is provided corresponding to each input/output device. In a data processing system, the central processing unit writes an input/output instruction, and the channel processor reads the subchannel control word and executes the input/output instruction.In a data processing system, the path leading to the input/output device is divided into multiple groups. At the same time, the subchannel control words of multiple input/output devices belonging to the same group can be
The channel processors are configured to be connected to queues using group control words as anchors, and the individual channel processors are configured to access each of the plurality of groups, and input/output instructions are written by the central processing unit. create a group control word list queue for a group in which a subchannel control word exists, and the channel processor accesses each of the groups by tracing the group control word list queue; When access progresses to a group located at the beginning or end of the group control word list queue, if the input/output instruction does not exist in any subchannel control word in the group, the channel processor , is characterized in that the group is configured to be extracted from the group control word list/queue. This will be explained below with reference to the drawings.

(E) Embodiment Fig. 1 shows the configuration of an embodiment of the present invention, Fig. 2 is an explanatory diagram for explaining the group control word list/queue referred to in the present invention, and Fig. 3 shows the main part configuration of an embodiment of the present invention. shows.

In FIG. 1, numerals 1 to 4 in the figure are input/output devices, 5 to 8 are input/output control devices, 9 to 12 are channels, 13 and 14 are channel processors, and 15 is a group including, for example, Single path group control word, 1
6 to 19 are subchannel control words, respectively, which are provided in one-to-one correspondence to the input/output devices 1 to 4, respectively, G1, G2, . . . are path groups according to the present invention, and MEM is a subchannel control word. The main storage, GCT1, GCT2... are the above paths and
In the control table corresponding to the group, 20 represents a queue anchor, and 21 represents a rotation pointer.

The central processing unit (CPU), not shown, is
An input/output command is issued to an individual input/output device, for example, device 1, and at this time, the input/output command is written on the corresponding subchannel control word 16. and one of the channel processors, for example channel processor 1.
3 reads an input/output command on the subchannel control word 16, the channel processor 13 executes the input/output command.

In the case of the present invention, a path leading to an input/output device is divided into a plurality of groups G1, G2, etc., and a control table is created corresponding to each group.
I am trying to prepare GCT1, SCT2...
In the illustrated case, a path/group control word 15 is provided in each control table GCT1, and
The control word 15 has a queue anchor 20 for each subchannel control word existing in the control table and in which an input/output command is described and queued. A rotation pointer 21 is also provided within the control word 15 to manage which subchannel control word is currently being processed by the plurality of channel processors 13 and 14 shown in the figure. .

In the illustrated configuration, input/output instructions for input/output devices belonging to one group are
Only one is executed at a time. For this reason, a waiting state occurs within the group, but there is no conflict between the groups. That is, it is sufficient for each of the plurality of channel processors 13 and 14 to check the contents of the rotation pointer 21, read queues in the group that are currently waiting for processing, and process them.

FIG. 2 shows the group control word list according to the present invention.
It is an explanatory diagram explaining the queue, and the reference numeral 1 in the diagram
3, 14, and 15 correspond to FIG. Also 2
2 represents a central processing unit, 23 represents a group control word list queue anchor, and 24 represents a group control word list queue. In addition, the reference numeral 1 in the diagram
5-i (i is 1, 2, 3...) is the above-mentioned path group control word corresponding to group i, and the line extending downward in the figure is the subchannel control word in which the input/output command is described in the group. This indicates that a word (16, 17, etc. shown in FIG. 1) is present. In addition, in the case shown, group numbers 1, 2,...
... are concatenated on the list queue 24 in this order, but originally they would be concatenated in a random order. Furthermore, in the illustrated case, there are no subchannel control words describing input/output commands in groups 15, 16, 17, and 18;
is not connected to the list queue 24.

Group control word list queue anchor 23
can be considered to exist in the main memory MEM shown in FIG. If it is written, the process will be as follows. That is, the group i to which the written subchannel control word (SCW) belongs is already in the list queue 2.
4, the subchannel control word is connected to the queue in the control table belonging to the group i. If the group i is not yet concatenated on the list queue 24, the subchannel control word (SCW) is concatenated to the queue in the control table of group i, and the group i is, for example, the top of the list queue 24. connected to. and each channel processor 13
14 sequentially scans, fetches, and dequeues the groups on the list/queue 24 and executes each input/output command.

A group that has been cut out (dequeued) from the list queue 24 is cut out as follows. That is, for example, the second
In the illustrated group "11", the subchannel control word (SCW) in which the input/output command is written no longer exists, and is in a state where it can be extracted. However, if the above-mentioned extraction is attempted at that point, in the case shown in FIG. 2, it is necessary to perform queue processing or the like to connect group "12" next to group "10", and the overhead cannot be ignored. For this reason, in the example shown in FIG. 2, if the group "14" located at the end of the list queue 24 is cut out, the relevant Make sure to cut out group "14". If you do this, the list
Groups that can be cut out will remain on the queue 24, but once the group is at the end, it will be cut out, so it will not remain on the list queue 24 forever. .

In the above explanation, when group i is connected to the list queue 24, it is connected to the beginning of the list queue 24, and when it is cut out, it is located at the end of the list queue 24. The explanation was made assuming that it is cut out in a state where it is cut out. However, when connecting to the list queue 24, it is also possible to connect to the end of the list queue 24 and cut out from the beginning of the list queue 24. In the present invention, the directions of the connection and the cut-out are arbitrary and may be in any direction, and there is no problem with overhead.

FIG. 3 shows the main part configuration of an embodiment of the present invention, and the reference numerals 23, 15-1, 15-2, . . .
corresponds to Fig. 2. Each path group control word 15-i has a field F that indicates whether the group is connected to the list queue 24, and which path group control word 15-j is next to itself. It has a pointer P1 that indicates whether to point the subchannel control word (SCW) within its own group, a pointer P2 that indicates the beginning of the queue for the subchannel control word (SCW) in its own group, and a pointer P3 that indicates the end. If each pointer is invalid (INVALiD), it means that there is nothing following it on the queue.

Each channel processor 13, 14 has a path group control word 15- on list queue 24, respectively.
The process follows i. If there is no longer a queue for the subchannel control word (SCW) in the group located at the end of the list queue 24 at that point in time (for example, group 14 in the figure), then the path
Group control words 15-14 to list queue 24
Try to cut it out.

(F) Effects of the Invention As explained above, according to the present invention, a rotation algorithm is adopted between groups, and a group control word list queue is provided, so that the above-mentioned rotation algorithm can be efficiently implemented. can be executed. Also list
Even when dequeueing a group from a queue, minimal processing is sufficient.

[Brief explanation of drawings]

FIG. 1 shows the configuration of an embodiment of the present invention, FIG. 2 is an explanatory diagram illustrating a group control word list/queue according to the present invention, and FIG. 3 shows the configuration of a main part of an embodiment of the present invention. In the figure, 1 to 4 are input/output devices, respectively.
3 and 14 are channel processors, and 15 is a path processor.
Group control word, 16 to 19 are subchannel control words, 23 is group control word list queue.
Anchor 24 represents a group control word list queue.

Claims (1)

[Scope of Claims] 1. A system comprising at least a storage device, one or more channel processors, and a plurality of input/output devices, wherein a central processing unit inputs information on a subchannel control word generated corresponding to each input/output device. In a data processing system in which an output command is written, and the channel processor reads the subchannel control word and executes the relevant input/output command, the path leading to the input/output device is divided into multiple groups, and the paths are divided into the same group. The subchannel control words of multiple input/output devices belonging to the group can be
The channel processors are configured to be connected to queues using group control words as anchors, and the individual channel processors are configured to access each of the plurality of groups, and input/output instructions are written by the central processing unit. create a group control word list queue for a group in which a subchannel control word exists, and the channel processor accesses each of the groups by tracing the group control word list queue; When access progresses to a group located at the beginning or end of the group control word list queue, if the input/output instruction does not exist in any subchannel control word in the group, the channel processor An instruction queue management processing method characterized in that the group is configured to be extracted from the group control word list queue.