JP3080340B2 - Access mediation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an information processing apparatus, a communication exchange, in particular, an ATM exchange, and other systems having a plurality of resources commonly connected by a bus.
Here, the resource refers to a memory device, an output device, a display device, an input device, a printing device, a functional unit, and other facilities including hardware for operating the system.

[0002] The present invention relates to arbitration of a plurality of access requests generated within a system with respect to a plurality of shared resources arranged in one system.

[0003]

2. Description of the Related Art Arbitration of an access request according to the prior art will be described with reference to FIG. FIG. 6 is a conceptual diagram illustrating the operation of the ring arbiter. The number of the resource of the request destination is displayed as an access request one by one from each of the request sources R (1) to R (8). The arbitration control is executed for each resource. Now, the arbitration control is executed for the m-th resource S (m) in FIG. Each request source R (1) to R
The access request from (8) is searched to determine whether any of the access requests has issued an access request to the resource S (m). Now, in this example, the second request source R
(2) issues an access request to the m-th resource.
In the arbitration control, when this is found, this request source is connected to the resource S (m). When one is connected, the other request sources are disconnected.

If there is only one request source R (1) to R (8) issuing an access request to the m-th resource S (m), the request is immediately accepted. If so, arbitration is performed for the conflict between them, one is selected, and the request is accepted. The arbitration logic can be set variously. Here, it is assumed that the processing is circulated and executed like the request generation sources R (1), R (2),..., R (n). This logic is performed equally for each request source R (1) -R (8).
(1) Priorities can be assigned to R (8), and any other logic can be set. This is based on the control method of the ring arbiter, and a network that allows a plurality of request sources to access a plurality of resources can be configured by combining a plurality of configurations as shown in FIG.

FIG. 7 shows an example of a network configuration. FIG. 7 is a diagram showing a network configuration. In this model, there are eight access request sources R (1) to R (8) and eight resources S (1) to S (8) for receiving the access requests. These are connected to the input terminal group and the output terminal group of the matrix switch means, respectively. The matrix switch means may be provided with hardware having a matrix configuration as shown in the figure, or may be a virtual one constituted by a logic circuit having a matrix function as shown and capable of transmitting an access request. The number of access request sources and the number of resources need not necessarily be equal.

The access request sources R (1) to R (8) generate access requests one after another. Since an access request is generated according to the circumstances of the source, a plurality of access requests may simultaneously compete for one resource. The contention is arbitrated by the matrix switch means, and one access request source is transmitted to one request destination resource. At this time, ring arbiter RA
(1) to RA (8) sweep the access request as indicated by the arrows in FIG. 7, and when the corresponding access request is reached, the access request is rejected via the intersection C (n, m). Only one is transmitted to the resource side, and the resource accepts the access request.

When one access request is accepted,
Information indicating that the request has been accepted is sent to the request source that sent the access request. By receiving one access request, another access request sent to the ring arbiter is waited, and the other access request is detected at the next timing or at the next timing. After the access request is accepted, processing such as transfer of necessary data via the matrix switch means or another bus signal line is executed.

[0008]

In such arbitration control of access requests, each of the ring arbiters RA (1) to RA (8) for performing arbitration in the case of contention requires each request in one time slot. Only one access request issued from the source can be accepted.

In the prior art apparatus shown in FIG. 6, the number of request sources R (1) to R (8) is eight, but this number is actually tens or hundreds. At this time, the speed at which the ring arbiter makes a round is a time that cannot be ignored.

An object of the present invention is to provide an access arbitration apparatus which shortens the contention arbitration time by dividing the ring arbiter and processing it in parallel.

[0011]

According to the present invention, an access request generated from a plurality of N request sources is selected one by one for each time slot, and one access request shared by the N access request sources is selected. An access arbitration device that gives access rights to resources.

Here, it is a feature of the present invention that the N request sources are configured such that the priority order at which the access request is selected is fixed in advance in a ring shape, and the access right is obtained immediately before. The access request sources are arranged in such a manner that the priorities of the access request sources sequentially fall to the lowest order, and the N is divided so as to divide the order according to the order of the priorities.
Request request sources are divided into a plurality of groups, and first arbitration means for selecting the highest priority access request for each time slot in each of the plurality of groups, and selection by the first arbitration means The access requests of the respective groups are made to correspond to the above-mentioned ring shape, and one obtained for each access slot immediately before that is arranged so as to sequentially fall to the lowest priority. And second arbitration means for selecting the highest priority and giving access right.

The first arbitration means may include means for cyclically scanning the request sources in the group in the order of arrangement, or means for scanning in parallel from the start point to the end point and from the end point to the start point in accordance with the arrangement. It is desirable to include.

The second arbitration means may be a means for cyclically scanning the request generation sources that have been arbitrated by the first arbitration means in the order of arrangement, or from a start point to an end point and from an end point to a start point according to the arrangement. It is desirable to include means for scanning in parallel.

[0015]

In the present invention, the priority source is divided into two groups by setting a boundary so that the request source having previously obtained the access permission has the lowest priority this time. The array that includes the request sources that have previously been granted access is the lower priority group, and the request sources included therein have a lower priority than any request sources included in another group.

Starting from the head of the array having the higher priority, the access permission is finally given to the request source having the first access request this time. Next time, a boundary is set so that the request source to which the access permission is given this time has the lowest priority.

As described above, the first arbitration unit executes the processing in parallel over a plurality of groups, so that the first arbitration unit can execute the processing in a short time in comparison with the case where a single large-scale ring arbiter is used without grouping. Competition arbitration can be performed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a configuration diagram of the first embodiment of the present invention.

According to the present invention, sixteen request sources R (1) to R (1) to R
The access request generated from (16) is incremented by 1 for each time slot.
Each of the 16 access request sources R is selected.
This is an access arbitration device that gives an access right to one resource S (1) shared by (1) to R (16).

The features of the present invention are as follows.
The six request sources R (1) to R (16) are fixed in advance in a priority order in which the access requests are selected in a ring shape, and the request source R of the access which has obtained the access right immediately before that. Assuming that the priorities of (1) to R (16) are sequentially dropped to the lowest order, the 16 request sources R are divided so as to divide the order according to the priority order.
(1)-R (16) is divided into two groups A and B,
First access right arbitration circuits CT (1) to CT (1) which are first arbitration means for selecting the highest priority access request for each time slot in each of the two groups A and B.
T (16) and the first access right arbitration circuits CT (1) -C
The access request of each group selected by T (16) is made to correspond to the above-mentioned ring shape, and the access request immediately before that is arranged in such a way that the access right falls sequentially to the lowest priority. Second access right arbitration circuits CTa (1) to C-c which are second arbitration means for selecting the highest priority one for each slot and giving an access right.
Ta (4) and CTb (1) to CTb (4).

Next, the operation of the first embodiment of the present invention will be described. 16 first access right arbitration circuits CT (1) to CT
Of (16), the first access right arbitration circuits CT (1) to CT (1) to CT
The set composed of (4) is the access right arbitration circuit group G (1), and the first access right arbitration circuits CT (5) to CT (8)
Access right arbitration circuit group G
(2) A set composed of the first access right arbitration circuits CT (9) to CT (12) is referred to as an access right arbitration circuit group G (3).
A set composed of the first access right arbitration circuits CT (13) to CT (16) is referred to as an access right arbitration circuit group G (4), and the first access right arbitration circuit groups G (1) to G (4)
(4) shows individual ring arbiters RA1 (1) to
RA1 (4) is patrolling.

Here, the previous first access right arbitration circuit C
Assuming that T (6) has obtained the access right, apart from the distinction of the access right arbitration circuit groups G (1) to G (4), the first access right arbitration circuit CT (6) and CT (7) Access right arbitration circuit CT (1) → CT (2) → CT (3)
→ Group A having priority in the order of → CT (4) → CT (5) → CT (6) and the first access right arbitration circuit CT (7) → CT
(8) → CT (9) → CT (10) → CT (11) → CT (12) → CT
It is divided into group B having priority in the order of (13) → CT (14) → CT (15) → CT (16).

There is a priority boundary between the group A and the group B, that is, between the first access right arbitration circuit CT (6) and the first access right arbitration circuit CT (7), and a drop is generated. is there. Any of the first access right arbitration circuits CT (7) to CT (16) of the group B has a higher priority than any of the first access right arbitration circuits CT (1) to CT (6) of the group A. Further, in the access right arbitration circuit groups G (3) and G (4) including the first access right arbitration circuits CT (7) to CT (16) belonging to the group B, the access right arbitration circuit group G (3) First access right arbitration circuit CT (9) ~
CT (12) has a higher priority than the first access right arbitration circuits CT (13) to CT (16) of the access right arbitration circuit group G (4).

That is, the first access right arbitration circuits CT (1) to CT (1) to C
This indicates the priority shown in the lower right frame of T (16).
The priorities are given for the sake of explanation and need not be grasped by the first access right arbitration circuits CT (1) to CT (16).

As described above, when the 16 first access right arbitration circuits CT (1) to CT (16) are divided, the boundaries of the groups A and B exist in the ring arbiter RA1 (2), Arbiter RA1 (1), RA1 (3), RA1 (4)
Access right arbitration circuits CT (1) to CT (4) belonging to
, CT (9) to CT (12) and CT (13) to CT (16) belong to one of the groups A and B. Each of the first access right arbitration circuits CT (1) to CT (16) recognizes only this group type. These ring arbiters RA1 (1)
In RA1 (4), at most one candidate is selected at one access opportunity. If the candidate belongs to group A, a flag output Ca is output, and if the candidate belongs to group B, a flag output Cb is output. . Therefore, flag outputs Ca and Cb are not output simultaneously.

The flag output Ca or Cb is supplied to the second access right arbitration circuits CTa (1) to CTa (4), CTb
(1) Access request to CTb (4). These second access right arbitration circuits CTa (1) to CTa (4),
CTb (1) to CTb (4) are ring arbiters RA1 (1)
ＲＡRA1 (4) and the information of the group A or B to which it belongs.

The ring arbiter RA2 includes second access right arbitration circuits CTa (1) to CTa (4) and CTb (1) to CTb.
(4). The boundary of the ring arbiter RA2 is between the second access right arbitration circuits CTa (k) and CTb (k) corresponding to the ring arbiter RA1 (k) having previously obtained the access right.

However, CTa (k) and CTb (k) are a pair, and the access permission obtained from either is given to the same RA1 (k).

In FIG. 1, the boundary of the ring arbiter RA2 is defined by the second access right arbitration circuits CTa (2) and CTb.
It is between (2). Therefore, the second access right arbitration circuit C
Ta (1), CTb (1) and CTa (2) are group A, and the second access right arbitration circuits CTb (2) and CTa (3)
, CTb (3), CTa (4) and CTb (4) belong to group B
Becomes The circulating order of the ring arbiter RA2 is determined by the second access right arbitration circuit CTb (1) → CTa (1) → CTb (2) →
CTa (2) → CTb (3) → CTa (3) → CTb (4) → C
Ta (4) → CTb (1). The first candidate of group B has a higher priority than the first candidate of group A. This means that the first candidate selected from the ring arbiter RA1 (k) can be finally granted access permission to one of the access requests by the ring arbiter RA2.

The above operation will be described more specifically.
In the ring arbiter RA1 (1) comprising only the group A, the first access right arbitration circuit CT (1) at the top is given the first priority, and in the ring arbiter RA1 (2) comprising the groups A and B, The first access right arbitration circuit CT (7) belonging to the group B and belonging to the group B is given the first priority, and each of the ring arbiters RA1 (3) and RA1 (4) comprising only the group B has the first priority. Access right arbitration circuits CT (9) and CT (1
3) is given the first priority.

Among these, if the first access right arbitration circuits CT (1) to CT (16) to which the access request is input are represented by ●, the priority order is determined by the ring arbiter RA1 (1). In the first access right arbitration circuit CT (3) and the ring arbiter RA1 (2), the first access right arbitration circuit CT (5) and the first access right arbitration circuit CT are used in the ring arbiter RA1 (3). (9), Ring Arbiter RA1
In (4), the first access right arbitration circuit CT (14)
Becomes At the same time, the second access right arbitration circuit CTa
A flag output Ca or Cb is output for (1) to CTa (4) and CTb (1) to CTb (4). The flag output Ca and the ring arbiter RA1 are output in the ring arbiter RA1 (1). In (2), the flag outputs Ca,
In the ring arbiter RA1 (3), the flag output C
b, a flag output Cb is output from the ring arbiter RA1 (4). Therefore, of the second access right arbitration circuits CTa (1) to CTa (4) and CTb (1) to CTb (4), the second access right arbitration circuits CTa (1) and CTa (1)
(2), CTb (3), and CTb (4) are input with the access requests indicated by ●. Second access right arbitration circuit CTa
The priority in (1) to CTa (4) and CTb (1) to CTb (4) is located at the boundary, and the second access right arbitration circuit CTb (2) belonging to group B is ranked first and the second Access right arbitration circuit CTa (3) → CTb (3) → CTa (4) →…
, The second access right arbitration circuit CTb
The access request entered in (3) is selected. The ring arbiter RA1 (3) receives this selection information, and the first access right arbitration circuit CT (9) is finally given an access permission.

The next boundary position is between the first access right arbitration circuits CT (9) and CT (10) in the first access right arbitration circuits CT (1) to CT (16). Second access right arbitration circuits CTa (1) to CTa (4), CTb (1) to
In CTb (4), the second access right arbitration circuit CT
a (3) and CTb (3).

As described above, according to this operation, the arbitration by the large undivided ring arbiter in the conventional example and the result are the same, but since a plurality of access requests are processed simultaneously in parallel, the access request Competition arbitration time can be shortened.

Next, the output procedure of the flag outputs Ca and Cb in the first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a diagram showing a procedure for outputting a flag. This is a description of the portion corresponding to the access right arbitration circuit group G (2) in FIG. 1, but in order to make the description easier to understand, here, eight request generation sources R (1) to R (8) are used. )
It is assumed that there are eight first access right arbitration circuits CT (1) to CT (8) corresponding thereto.

Each first access right arbitration circuit CT (1) -C
T (8) holds state values st (1) to st (8) indicating whether each belongs to group A or B. When the state value st (n) (1 ≦ n ≦ 8) holds the logical value “0”, the first access right arbitration circuit CT
(n) belongs to group A, and the first access right arbitration circuit CT (n) belongs to group B when the state value st (n) holds the logical value "1".

Here, assuming that the request source R (3) has obtained the access right last time, the request source R (3) has the lowest priority this time. Therefore, the boundary between group A and group B is determined by the first access right arbitration circuit CT (3).
And CT (4).

In FIG. 2, the request sources R (2) and R (3)
, R (6) and R (7) generate access requests. The ring arbiter RA1 (k0) is a first access right arbitration circuit CT
(1) -CT (8), the first access right arbitration circuit C of the request source R (6) having the highest priority in the above-described procedure.
Select T (6) as the first candidate.

In parallel with this, the ring arbiter RA1 (k0)
Controls the flag output Ca or Cb. The ring arbiter RA1 (k0) is connected to the first access right arbitration circuit CT (8)
The scanning is sequentially started from to (1). At the start of this scanning, the flag output is Ca. The first access right arbitration circuit CT (8) belongs to group B,
Although the logical value of the state value st (8) is "1", there is no access request here, and the ring arbiter RA1 (k0) leaves the flag output Ca as it is, and the next first access right arbitration circuit C
Scan T (7). First access right arbitration circuit CT (7)
Has an access request, and the flag output Ca is inverted to Cb because the state value st (7) is the logical value "1". Since Group B has priority, the following Group A
Access right arbitration circuits CT (3) and CT belonging to
(2) also has an access request, but these are flag output Cb
Is not allowed to be inverted, the flag output Cb
Are the second access right arbitration circuits CTa (1) to CT
a (4) and transmitted to CTb (1) to CTb (4).

Thus, the first candidate of the second access right arbitration circuits CTa (1) to CTa (4) and CTb (1) to CTb (4) is the request source R (6). , It is reported that it belongs to group B.

Next, referring to FIG. 3, the second access right arbitration circuits CTa (1) to CTa in the first embodiment of the present invention.
(4) The operation of CTb (1) to CTb (4) will be described. FIG.
Are the second access right arbitration circuits CTa (1) to CTa (4),
It is a figure which shows CTb (1) -CTb (4) and ring arbiter RA2. Second access right arbitration circuit CTa (1)
CTa (4), CTb (1) to CTb (4) inherit the groups A and B in the first access right arbitration circuits CT (1) to CT (16), and the second access right arbitration circuit CTa
The group A in (1) to CTa (4) and CTb (1) to CTb (4) includes the second access right arbitration circuits CTa (1) and C
Ta (2) and CTb (2), and their attributes are represented by the state value sta.
(n) or stb (n). The logical value of the status value sta (n) or stb (n) is group A
Is "0" if the group belongs to group B, and "1" if it belongs to group B.

In FIG. 3, the request source R (2) has previously obtained the access right, and this time there is a boundary between the second access right arbitration circuits CTa (2) and CTb (2). Any one of the second access right arbitration circuits CTa (1) to CTa (4) and CTb (1) to CTb
(4) At most one candidate is selected. Here, regardless of whether the second access right arbitration circuit CTa (n) or CTb (n) has been granted access, the OR circuit OR (n) accesses the first candidate of the request source R (n). Permission will be given.

In FIG. 3, in group A, first access arbitration circuit groups G1 and G2 generate first candidate access requests, respectively. In group B, first access arbitration circuit group G3 generates first candidate access requests. When an access request is generated, the ring arbiter RA (2) issues a second access right arbitration circuit CTb (2) → CTa (3) → CTb (3).
→ CTa (4) → CTb (4) → CTa (1) → CTb (1) →
One round of CTa (2), CTb (3) with the highest priority
The CTb (3) gives the access permission to the first access right arbitration circuit group G3 as a response to the first access right arbitration circuit group G3 by the OR circuit OR (3). In the access right arbitration circuit group G (3), a final access permission is given to the first candidate already selected in the first access right arbitration circuit group G (3) in response to the access permission. Next,
The boundary between groups A and B is set to a second access right arbitration circuit CT.
a (3) and CTb (3), and the second access right arbitration circuits CTa (1), CTb (1), CTa (2), CTb
(2), CTb (3) is group A, and second access right arbitration circuits CTb (3), CTa (4), CTb (4) are group B. At the same time, the first access right arbitration circuit CT
In (1) to CT (16), new grouping is also performed.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a view showing a second embodiment of the present invention. In the second embodiment of the present invention, the acyclic ring arbiters c1, c
2, cb and ca are used. Acyclic ring arbiter c1
And c2 connect groups A and B, scan from the first access right arbitration circuit CT (1) having the logical value "0" and having the highest priority of group A, and non-cyclic ring arbiter c1 The logical value is inverted by the first access right arbitration circuit CT (2) of the highest priority that has been requested to access at A. The non-cyclic ring arbiter c2 inverts the logical value in the first access right arbitration circuit CT (6) of the highest priority which has been requested to access in the group B.

That is, the first access right arbitration circuit CT (n) whose logic value is inverted by the non-cyclic ring arbiters c1 and c2 is the first candidate spare candidate selected only in the group A or B, respectively. It is. Therefore, there are at most two preliminary candidates.

Further, the acyclic ring arbiter cb starts scanning from the first access right arbitration circuit CT (8), and the state value st (n) having the access request of the first access right arbitration circuit CT (n). ), A flag is set, that is, the logical value of the non-cyclic ring arbiter cb is set to “1”, whereby the presence or absence of an access request from the group B is transmitted to the group A. Therefore, the preliminary candidate of group A is canceled when there is an access request to group B, and the group B spare group by the non-cyclic ring arbiter c2 is canceled.
Is the first candidate.

In FIG. 4, request sources R (2) and R (3)
, R (6), R (7), the non-cyclic ring arbiter c1 starts scanning from the first access right arbitration circuit CT (1), and the logical value of the state value st (2) Is "0", a flag is set, that is, the logical value of the non-cyclic ring arbiter c1 is set to "1". The non-cyclic ring arbiter c2 starts scanning from the first access right arbitration circuit CT (1), Since the logical value of the state value st (6) is "1", a flag is set, that is, the acyclic ring arbiter c2
Is set to "1", whereby the first access right arbitration circuit CT (2) becomes a spare candidate for group A, and the first access right arbitration circuit CT (6) becomes a spare candidate for group B. The non-recursive ring arbiter cb starts scanning from the first access right arbitration circuit CT (8), and the logical value of the state value st (7) of the first access right arbitration circuit CT (7) is "1". , A flag is set, that is, the logical value of the non-cyclic ring arbiter cb is set to “1”. With this, the presence / absence of an access request from the group B is transmitted to the group A, so that the spare candidate of the group A is canceled. , The access request for the spare candidate of group B by the non-cyclic ring arbiter c2 is the first candidate.

The non-cyclic ring arbiter ca starts scanning from the first access right arbitration circuit CT (8) in the same manner as cb, but since the flag has already been set in the non-cyclic ring arbiter cb, the logical value The inversion is prevented, and the signal is transmitted with the logical value “0”.

The advantage of the second embodiment of the present invention is that the arbitration time is twice as fast as that of the cyclic ring arbiter by using the non-cyclic ring arbiters c1, c2, cb and ca in parallel. What you can do.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a view showing a third embodiment of the present invention. In the third embodiment of the present invention, the acyclic ring arbiters c1, c
2. Use cb. The non-cyclic ring arbiters c1 and c2 connect the groups A and B, scan from the second access right arbitration circuit CTa (1) having the logical value "0" and the highest priority of the group A, and The ring arbiter c1 inverts the logical value in the second access right arbitration circuit CT (1) of the highest priority which has been requested to access in the group A, and the non-cyclic ring arbiter c2 does not respond to the access request in the group B. The logical value is inverted by the first access right arbitration circuit CTb (3) having the highest priority.

That is, the second access right arbitration circuit CTa (n) or CTb (n) whose logical values are inverted by the non-cyclic ring arbiters c1 and c2 is the one in which only one is selected in the group A or B, respectively. This is one preliminary candidate. Therefore, there are at most two preliminary candidates.

Further, the non-cyclic ring arbiter cb starts scanning from the second access right arbitration circuit CTb (4),
Second access right arbitration circuit CTa (n) or CTb (n)
Status value sta (n) or stb with access request
If the logical value of (n) is "1", a flag is set, that is, the logical value of the acyclic ring arbiter cb is set to "1". As a result, the presence or absence of the access request from the group B is transmitted to the group A. If the access request is made to the group B, the spare candidate of the group A is canceled, and the access to the spare candidate of the group B by the non-cyclic ring arbiter c2 is performed. The request is the first candidate. Here, regardless of which of the second access right arbitration circuits CTa (n) and CTb (n) has been granted access, the first OR of the first access right arbitration group G (n) is performed by the OR circuit OR (n). The candidate will be given access permission.

In FIG. 5, the first access right arbitration circuit groups G (1) and G (2) each generate an access request in which the group A is the first candidate, and the first access right arbitration circuit group G ( 3), the non-cyclic ring arbiter c1 in which an access request in which the group B is the first candidate is generated, starts scanning from the second access right arbitration circuit CTa (1) with the logical value "0". Here, there is an access request to the second access right arbitration circuit CTa (1), and since the logical value of the state value sta (1) is "0", the logical value of the acyclic ring arbiter c1 is set to "1". Flip to That is, the first access arbitration circuit group G (2) is a spare candidate of the group A, and the non-cyclic ring arbiter c2
Has a logical value "0" and has a second access right arbitration circuit C
Scanning is started from Ta (1). Here, there is an access request to the second access right arbitration circuit CTb (3), and the state value s
Since the logical value of tb (3) is "1", the logical value of the acyclic ring arbiter c2 is inverted to "1". That is, the non-cyclic ring arbiter cb in which the first access arbitration circuit group G (3) is a spare candidate of the group B is
The second access right arbitration circuit CTb having a logical value "0"
Scanning is started from (4) toward CTa (1). An access request is issued to the second access right arbitration circuit CTb (3),
Since the logical value of the state value stb (3) is "1", the logical value of the acyclic ring arbiter cb is inverted to "1".
Here, since the presence or absence of the access request from the group B is transmitted to the group A, the first access arbitration circuit group G (2), which is a spare candidate of the group A, is canceled and the first access arbitration circuit group G (3) is the final selection candidate. The second access right arbitration circuit CTb (3) grants access to the first access arbitration circuit group G (3) by the OR circuit OR (3). In response, the first access arbitration circuit group G (3) gives final access permission to the first candidate already selected in the first access arbitration circuit group G (3). The boundary between groups A and B is set to the second access right arbitration circuit CTa (3).
And CTb (3), the second access right arbitration circuits CTa (1), CTb (1), CTa (2), CTb (2),
CTb (3) is group A, and the second access right arbitration circuits CTb (3), CTa (4), and CTb (4) are group B. At the same time, the first access right arbitration circuits CT (1) to C
A new grouping is also performed at T (16).

An advantage of the third embodiment of the present invention is that the non-cyclic ring arbiters c1, c2 and cb are used in parallel,
The arbitration time is twice as fast as that of the cyclic ring arbiter.

In the first to third embodiments of the present invention, the number of request generation sources R (1) to R (16) is determined and described, but the number can be arbitrarily configured.

Although the above description has been made assuming that there is hardware called a ring arbiter, a practical design can be executed by a logical operation developed on a memory area by a program control circuit.

Returning to FIG. 7, the above description is based on the resource S (1).
Is a description of one row of the connected matrix,
A network as shown in FIG. 7 can be configured by using a plurality of these columns. Also, the request source R (1) to R
(8) and the number of resources S (1) to S (8) can be arbitrarily configured, but in reality are tens or hundreds.

[0057]

As described above, according to the present invention, since the access request search can be divided into a plurality of pieces and processed in parallel, the contention arbitration time is greatly reduced.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a procedure for outputting a flag.

FIG. 3 is a diagram showing a second access right arbitration circuit and a ring arbiter RA2.

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

FIG. 5 is a view showing a third embodiment of the present invention.

FIG. 6 is a conceptual diagram illustrating the operation of a ring arbiter.

FIG. 7 is a diagram showing a network configuration.

[Explanation of symbols]

A, B groups CT (1) to CT (16) First access right arbitration circuit CTa (1) to CTa (4), CTb (1) to CTb (4) Second access right arbitration circuit Ca, Cb Flag Outputs c1, c2, ca, cb Acyclic ring arbiters G (1) to G (4), G (n) Access right arbitration circuit group OR (1) to OR (4) OR circuit R (1) to R (R) (16) Request source RA (1) to RA (8), RA1 (1) to RA1 (4), RA2
Ring arbiter S (1), S (m) resource st (1) to st (8), sta (1) to sta (4), stb
(1) to stb (4) Status value

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-72752 (JP, A) JP-A-58-171541 (JP, U) IEICE Technical Report SSE 91-157 1992 Spring Meeting of the Society of Japan B-451 (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/28 H04L 12/56 G06F 13/37 G06F 13/372

Claims (5)

(57) [Claims] An access request generated from a plurality of N request sources is selected one for each time slot,
In an access arbitration apparatus for granting an access right to one resource shared by a plurality of access request sources, the N request sources fix a priority in which the access request is selected in a ring form in advance. in, and assuming that the priority of the access request source has gained access immediately before are arranged by providing a boundary priority to sequentially fall to the lowest, before Symbol N pieces follow in order of its priority Request sources are divided into multiple groups, and each of the multiple groups is selected for each time slot.
Access request belongs to any of the priority boundaries
First arbitration means (RA1) for selecting an access request having the highest priority together with the information of the above, and making the access requests of each group selected by the first arbitration means correspond to the ring shape, and Based on the information, it is assumed that one having the access right immediately before is sequentially arranged to fall to the lowest priority. An access arbitration device comprising: a second arbitration means (RA2) for providing the access arbitration. 2. The access arbitration apparatus according to claim 1, wherein the first arbitration unit includes a unit that scans request sources in the group cyclically in the arrangement order. 3. The access arbitration apparatus according to claim 1, wherein said first arbitration means includes means for scanning request sources in said group from a start point to an end point and from an end point to a start point in parallel according to an arrangement thereof. apparatus. 4. The access arbitration apparatus according to claim 1, wherein the second arbitration unit includes a unit for cyclically scanning the request generation sources that have been arbitrated by the first arbitration unit in the arrangement order. 5. The second arbitration means includes means for scanning in parallel from the start point to the end point and from the end point to the start point in accordance with the arrangement of the request sources that have been arbitrated by the first arbitration means. The access arbitration device according to claim 1.