JPH1166024A - Crossbar switch changeover system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crossbar switch changeover system with which the generation of competition can be decreased without expanding system scale. SOLUTION: Crossbar switches 10, 11 and 12 have a function for outputting an output port information signal (P), which shows whether its own output port is in use or not, to crossbar switches 00, 01 and 02 on the preceding stage. The crossbar switch 01, to which the request of data transfer is inputted from an information processor PE 03, receives this output port information signal (P) from the crossbar switches 10, 11 and 12 and sends the crossbar switch 11 having the idle output port. By first reading the idle state of the output port in the switch on the preceding stage, the basic data transfer path of a minimum hardware can be effectively utilized to a maximum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a crossbar switch switching system, and more particularly to a crossbar switch switching system for switching a data transfer path between a plurality of information processing devices.

[0002]

2. Description of the Related Art An example of this type of crossbar switch switching system is described in Japanese Patent Application Laid-Open No. 8-77127.

This is composed of a processor, a relay switch and a crossbar switch, a host computer or an SVP. The relay switch and the crossbar switch are composed of a path instruction circuit, a path information change circuit, a detour instruction circuit and a coincidence determination circuit (relay switch). For example, when a message is broadcast from PE01, a broadcast message is first sent to a specific crossbar switch (for example, by a transfer control information in the message and path information set in the relay switch and the crossbar switch by the host computer or SVP). , 135) and broadcast from there. When there is a failure in the partial network in the transfer path of the one-to-one transfer message, first,
By-pass transfer to a specific crossbar switch, and one-to-one from there
It is to transfer.

Next, an outline of the prior art will be described with reference to FIGS. FIG. 4 is a diagram showing a request competition state in the conventional crossbar switch switching system, FIG. 5 is a diagram showing an internal arbitration system of the system, and FIG. 6 is a diagram showing a centralized management system of the system.

In the crossbar switch, competition for the same output port may occur due to its specifications. In the conventional conflict avoidance technique, a plurality of input requests request the same output port in a certain crossbar switch. Each PE has one input port and one output port.

Consider a system configuration in which three-input three-output crossbar switches as shown in FIG. 4 are connected in three stages.

[0007] A conventional crossbar switch switching system includes:
The information processing devices PE00-08 on the transmission side, the information processing devices PE10-18 on the reception side, and the crossbar switches 100-102, 110-112, 1 for switching these connections.
20 to 122.

The output ports of PE00 to PE02 are connected to input ports 0 to 2 of crossbar switch 100,
The output ports of 03 to PE05 are crossbar switches 101
And the output ports of PE06 to PE08 are connected to the input ports 0 to 0 of the crossbar switch 102.
Connected to 2.

The output port 0 of the crossbar switch 100 is connected to the input port 0 of the crossbar switch 110, the output port 1 of the crossbar switch 100 is connected to the input port 0 of the crossbar switch 111, and the output port 2 of the crossbar switch 100 is connected to the crossbar switch. Connected to input port 0 of switch 112.

The output port 0 of the crossbar switch 101 is connected to the input port 1 of the crossbar switch 110, the output port 1 of the crossbar switch 101 is connected to the input port 1 of the crossbar switch 111, and the output port 2 of the crossbar switch 101 is connected to the crossbar switch. Connected to input port 1 of switch 112.

The output port 0 of the crossbar switch 102 is connected to the input port 2 of the crossbar switch 110, the output port 1 of the crossbar switch 102 is connected to the input port 2 of the crossbar switch 112, and the output port 2 of the crossbar switch 102 is connected to the crossbar switch. Connected to input port 2 of switch 112.

The crossbar switches 110 to 112 and the crossbar switches 120 to 122 are similarly connected.

The output ports 0 to 0 of the crossbar switch 120
2 is connected to input ports of PE10 to PE12, and output ports 0 to 2 of the crossbar switch 121 are connected to PE13 to PE1.
5, and the output ports 0 to 2 of the crossbar switch 122 are connected to the input ports of the PEs 16 to 18.

Here, in the crossbar switch 110,
Output port 0 by request 00 from input port 0
It is assumed that the process of switching to has been performed. At this time, if a request 01 for switching from the input port 1 to the output port 0 comes, the request 01 coming from the input port 1 loses the contention, and holds data in a buffer or the like and waits until the own request is selected. Will be.

The cause of this conflict is that the switch or the information processing device at the preceding stage sends a request without grasping the state of the switch at the next stage or later. That is, the request 01 is output port 0 of the crossbar switch 110.
Issued without knowing that there is a conflict. In this case, the output port 1 may be selected in the crossbar switch 101, but this determination cannot be made in this configuration.

There are two ways to solve this problem. One is the crossbar switches 110 to 11 shown in FIG.
In this method, a detour bus is set up between the two. Since the configuration of FIG. 5 is the same as that of FIG.
The description is omitted.

That is, the request 01 that has lost the contention in the crossbar switch 110 passes through the bypass path L1 from the horizontal crossbar switch 111 or the bypass path L2.
And data can be output from the crossbar switch 112 in the horizontal direction.

Similarly, when the competition is lost in the crossbar switch 111, data can be output from the horizontal crossbar switch 110 via the bypass path L1 or from the horizontal crossbar switch 112 via the bypass path L3. .

Similarly, when the competition is lost in the crossbar switch 112, data can be output from the horizontal crossbar switch 111 via the bypass path L3 or from the horizontal crossbar switch 110 via the bypass path L2. .

This is an internal arbitration system which focuses only on the output ports of its own crossbar switch (in a broad sense, all horizontal crossbar switches in a certain stage) due to a request being input to the crossbar switch.

Another method is a centralized management method in which the ports used by all the crossbar switches 100 to 122 shown in FIG.

In this method, all the crossbar switches 100 to 122 and all the information processing devices P
By controlling the state of E00 to PE18,
The contention on the switching network can be prevented.

Another example of this type of crossbar switch switching system is described in JP-A-3-209550 and JP-A-1-25041.

[0024]

However, in the internal arbitration system, the contention occurs in the next-stage crossbar switch because it is determined whether or not the designated output port switching is possible based only on the request input into the own crossbar switch. I do not consider whether or not. For this reason, contention occurs in the next-stage crossbar switch that has transmitted the data. As a countermeasure for this, it is necessary to establish a horizontal bypass path between several switches or wait for processing by buffering the request.

On the other hand, in the centralized management system, all control information is collected at one point. Therefore, when the number of connected PEs becomes enormous, the amount of data to be processed also increases in proportion, and it is difficult to implement due to physical restrictions.

As described above, in the prior art, when the system scale is increased, there arises a problem that physical restrictions such as an increase in the amount of hardware for avoiding contention greatly hinder the feasibility of the system.

It is an object of the present invention to provide a crossbar switch switching system that can reduce the occurrence of contention without increasing the system scale.

[0028]

According to the present invention, there is provided a crossbar switch switching system for switching a data transfer path between a plurality of information processing apparatuses, comprising a front stage and a rear stage crossbar switch. The subsequent-stage crossbar switch has a notifying unit for notifying the preceding-stage crossbar switch of use state information indicating whether an output port of the own-stage crossbar switch is in use, and the preceding-stage crossbar switch is provided with the following-stage crossbar switch. It is characterized by having a switching control means for switching the connection with the subsequent crossbar switch based on the use state information from the switch.

According to the present invention, the idle state of the subsequent crossbar switch is actively read ahead by the hardware in the preceding crossbar switch, thereby maximally utilizing the basic data transfer path, which is the minimum hardware. However, the probability of occurrence of competition in the subsequent stage can be significantly reduced.

[0030]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing the operation of the preferred embodiment of the crossbar switch switching system according to the present invention. In the figure, the same components as those of the conventional example (FIG. 4) are denoted by the same reference numerals, and description thereof will be omitted.

The crossbar switch switching system according to the present invention comprises an input-side information processing device PE00-08, an output-side information processing device PE10-18, and crossbar switches 00-02, 10-12 for switching these connections. , 20
~ 22.

The connection between the information processing devices PE00 to PE22 and the crossbar switches 00 to 22 is the same as that of the conventional example (FIG. 4), and the description thereof will be omitted.

In this crossbar switch switching system,
The data transfer path between a certain information processing device (any of PEs 00 to 08) and a certain information processing device (any of PEs 10 to 18) has three patterns.

For example, the information processing devices PE00 and PE10
Between the information processing device PE00, the input port 0 and the output port 0 of the crossbar switch 00, the input port 0 and the output port 0 of the crossbar switch 10, the input port 0 and the output port 0 of the crossbar switch 20, and the information processing device PE10 And the input port 0 and output port 1 of the crossbar switch 00, the input port 0 and output port 0 of the crossbar switch 11, and the input port 1 and output port 0 of the crossbar switch 20 from the information processing device PE00. Second reaching the information processing device PE10 through the
From the information processing device PE00 through the input port 0 and output port 2 of the crossbar switch 00, the input port 0 and output port 0 of the crossbar switch 12, the input port 2 and the output port 0 of the crossbar switch 20, and the information processing device PE10. There is a third pattern that reaches.

FIG. 2 is an explanatory diagram of signals specific to the system. Referring to FIG.
20 to 22 are three output ports (0 to 0) of the own crossbar switch.
It has a function of transmitting an output port information signal P indicating the use state of 2) to each of the preceding crossbar switches.

For example, the crossbar switch 10 displays the use state of its own output port (0 to 3) by a 3-bit digital signal. As an example, “100” when the own output port 0 is in use, and “0” when the own output port 1 is in use.
10 and "001" when the own output port 2 is in use, and "000" when all output ports are free.

The output port information signal P is set to P1 from the own input port 0 to the crossbar switch 00, and is set to P2 from the own input port 1 to the crossbar switch 01.
Then, the local input port 2 notifies the crossbar switch 02 as P3. Note that the same applies to the crossbar switches 11 to 12 and 20 to 22, and the description is omitted.

Next, a description will be given of a crossbar switch at the preceding stage for receiving these output port information signals P.

For example, the crossbar switch 00 receives an output port information signal P1 from the crossbar switch 10 via its own output port 0, and the crossbar switch 01 outputs its own output port 0.
, And the crossbar switch 02 receives the output port information signal P3 from the crossbar switch 10 via its own output port 0.

Therefore, the crossbar switch 00 receives the output port information signal P of 3 bits + 3 bits + 3 bits = 9 bits. The crossbar switch 01
The same applies to 〜02, 10-12, and the description is omitted.

Crossbar switches 10 to 12, 20 to
Reference numeral 22 also has a function of transmitting a cancel request signal (1-bit signal) Q to the preceding crossbar switch.

For example, the crossbar switch 10 sends a cancel request signal Q1 to the crossbar switch 00, a cancel request signal Q2 to the crossbar switch 01,
Cancel request signal Q3 for crossbar switch 02
Are sent respectively. The crossbar switches 11 to 12,
Since the same applies to 20 to 22, the description is omitted.

Next, the operation of this embodiment will be described with reference to FIG.

In the crossbar switch 10, it is assumed that a request 00 has been received from the crossbar switch 00 and the output port 0 has been used. Previous crossbar switch 0
0 to 02 know at this time that the output port 0 of the crossbar switch 10 is in use based on the 9-bit information.

In this state, an output port designation is made such that data is transferred from PE03 through the crossbar switch 01, through one of the output ports 0 of the crossbar switches 10 to 12, and through the output port 1 of the crossbar switch 20 to the PE11. It is assumed that a request 01 to which information is added is issued.

The request 01 arriving at the crossbar switch 01 knows that the output port 0 of the crossbar switch 10 is used as described above. Therefore, the output port 0 of the crossbar switch 01 is excluded from the selection target of the request 01, and the crossbar switch 11 or 12
Is transferred to the switch 20 through the output port 0 of the switch.

Since the crossbar switch 01 has two valid output ports, the request 01 is transferred to the crossbar switch 11 according to the priority order. Request 01
Since the output port 0 is supposed to be vacant when is input to the crossbar switch 11, it is possible to connect to the output port 0 and transfer data without conflict.

When this is considered in the entire system, the request is switched while always monitoring the state of the switch at the subsequent stage, so that the occurrence of competition due to concentration of requests can be avoided, and each crossbar switch operates efficiently. be able to.

However, if the output port 0 of the crossbar switch 10 is vacant and a request arrives at the same timing from the crossbar switches 00 and 01, for example, the output port 0
Competition may occur.

In this case, the output port 0 is obtained for one request according to the priority order, and the cancel request signal Q is returned to the crossbar switch having the lost request.

The previous-stage crossbar switch that has received the cancel request signal Q searches for an empty output port again, but since the next-stage output port that has competed last time has already been used, the same logic is used. Another free output port can be reselected.

Next, the operation of the present embodiment will be described in detail with reference to FIGS. FIG. 3 is a flowchart showing details of the operation of the system.

FIG. 3 shows the operation of each crossbar switch when the request 01 is output from the information processing device PE03 to the output port 0 of the crossbar switch 10 via the crossbar switch 01.

Referring to FIG. 3, first, crossbar switch 0
1 checks whether the output port 0 of the crossbar switch 10 is valid (vacant) or not (in use) (S1). If it is valid, it is checked whether or not the output port of the crossbar switch 01 is valid (S2). If this is also valid, the request 01 is transmitted from the output port of the crossbar switch 01 (S3).

Next, the request 01 is input from the crossbar switch 01 to the input port 1 of the crossbar switch 10 (S4).

At this point, the output port 0 of the crossbar switch 10 should be vacant.
The crossbar switch 10 checks whether a request has arrived from the other crossbar switches 00 and 02 at the same timing as the request from 1 (S5).

If another request has arrived at S5 and the contention has been lost, the crossbar switch 10 transmits a cancel request signal Q2 to the crossbar switch 01 (S7). Then, the process returns to S1.

At S5, if there is no contention with another request or there is contention but the right is acquired, the request 01 is sent from the output port 0 of the crossbar switch 10 to the input port 0 of the crossbar switch 20. (S
6). The following is omitted.

On the other hand, when the output port 0 of the crossbar switch 10 is in use in S1, for example, the crossbar switch 1
Request 00 from crossbar switch 00 for 0
Has arrived, the crossbar switch 01 checks whether the output port 0 of the crossbar switch 11 is valid or not (S
11).

If the output port 0 is valid, steps S12 to S16 similar to steps S2 to S6 are executed.

On the other hand, if the output port 0 of the crossbar switch 11 is in use at S11, the crossbar switch 01 checks whether the output port 0 of the crossbar switch 12 is valid (S21).

If the output port 0 is valid, steps S22 to S26 similar to steps S2 to S6 are executed.

Then, at S21, the crossbar switch 12
If the output port 0 of the crossbar switch 01 is in use or the output port 2 of the crossbar switch 01 is in use in S22, the crossbar switch 01 sends a signal for notifying the request issuing PE03 of cancellation (S3).
1).

[0064]

According to the present invention, there is provided a crossbar switch switching system for switching a data transfer path between a plurality of information processing apparatuses, comprising a front stage and a rear stage crossbar switch, wherein the rear stage crossbar switch is its own crossbar switch. Notifying means for notifying use status information indicating whether or not the output port is in use to the preceding crossbar switch, wherein the preceding crossbar switch is configured based on use status information from the subsequent crossbar switch. Since the crossbar switch switching system is configured to have a switching control means for switching the connection with the subsequent crossbar switch,
By actively prefetching the empty state of the subsequent crossbar switch with the hardware in the previous crossbar switch, the contention probability in the subsequent stage is greatly increased while maximally utilizing the basic data transfer path, which is the minimum hardware Can be reduced to

Therefore, the detour processing in the prior art can be performed using an existing data path, and a data buffer at the time of occurrence of a conflict is not required. Also, there is no need for centralized management technology.

[Brief description of the drawings]

FIG. 1 is a diagram showing an operation of a preferred embodiment of a crossbar switch switching system according to the present invention.

FIG. 2 is an explanatory diagram of signals specific to the system.

FIG. 3 is a flowchart showing details of the operation of the system.

FIG. 4 is a diagram showing a contention state of a request in the conventional crossbar switch switching system.

FIG. 5 is a diagram showing an internal arbitration method of the system.

FIG. 6 is a diagram showing a centralized management system of the system.

[Description of Signs] 00-22 Crossbar Switch PE00-18 Information Processing Device

Claims (4)

[Claims] 1. A crossbar switch switching system for switching a data transfer path between a plurality of information processing devices, comprising a front stage and a rear stage crossbar switch, wherein the rear stage crossbar switch uses an output port of its own crossbar switch. Notifying means for notifying the use state information indicating whether or not is to the preceding stage crossbar switch, wherein the former stage crossbar switch communicates with the latter stage crossbar switch based on the use state information from the latter stage crossbar switch. A crossbar switch switching system comprising switching control means for switching a connection. 2. The switching control means, when recognizing from the use state information that an output port of the subsequent crossbar switch is in use, switches the connection of the output port to an empty subsequent crossbar switch. The crossbar switch switching system according to claim 1, wherein 3. The second notification that, when receiving a connection request from a plurality of the preceding crossbar switches simultaneously, notifies the crossbar switch other than the crossbar switch that accepts the request of the cancellation request information when the subsequent crossbar switch receives the connection request from the plurality of preceding crossbar switches. 3. The crossbar switch switching system according to claim 1, further comprising means. 4. The crossbar switch has a plurality of input ports and the same number of output ports as the number of the input ports that are selectively connected to each of the input ports. The corresponding input port of the subsequent crossbar switch is connected to each of the input ports of the foremost crossbar switch, the transmitting side information processing device is connected to each of the input ports of the foremost crossbar switch, and the reception port is connected to each of the output ports of the last crossbar switch. The crossbar switch switching system according to any one of claims 1 to 3, wherein a side information processing device is connected.