RING-PATTERN BUS CONNECTED INFORMATION PROCESSING APPARATUS, INFORMATION PROCESSING METHOD, AND STORAGE MEDIUM

• US 20100235609A1
• Filed: 03/09/2010
• Published: 09/16/2010
• Est. Priority Date: 03/13/2009
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Ishikawa, Hisashi, Inoue, Hirowo
• Granted Patent: US 9,239,813 B2
• Time in Patent Office: Days
• US Class Current: 712/29
• CPC Class Codes: G06F 13/38 Information transfer, e.g. on bus G06F13/14 takes precedence
• CPC Class Codes: G06F 15/17375 One dimensional, e.g. linear array, ring
• CPC Class Codes: G06T 1/20 Processor architectures; Processor configuration, e.g. pipelining

Abstract

In an information apparatus including a plurality of processing circuits connected to a ring bus, when processing speeds (throughput) of processing circuits are different or an amount of data in the processing circuit is increased or decreased, deadlock can occur or the throughput can be decreased in the ring bus. In order to solve this problem, a stall state of other processing unit is detected from a packet acquired from the ring bus and a packet is restricted from being newly generated by the processing circuit nor transmitted therefrom when other processing unit is in the stall state.

Claims

1. An information processing apparatus including a plurality of processing units communicably connected to a ring bus and configured to process information in order, and a first processing unit, which is one of the plurality of processing units, the apparatus comprising:

a transmission unit configured to, when the first processing unit is in a first state where the first processing unit does not process information acquired from the ring bus, transmit to the ring bus a packet indicating that the first processing unit is in the first state;

a detection unit configured to detect that a second processing unit, which is one of the plurality of processing units, is in the first state from a packet flowing in the ring bus; and

a control unit configured to, when the second processing unit is detected to be in the first state, restrict a packet having data processed by the first processing unit from being output to the ring bus.

2. The information processing apparatus according to claim 1,

wherein the first processing unit generates a new packet based on data processed by the first processing unit.

3. The information processing apparatus according to claim 1,

wherein the control unit does not restrict the transmission unit from transmitting a packet other than a new packet.

4. The information processing apparatus according to claim 1,

wherein the detection unit detects that the second processing unit behind the first processing unit in a processing order is in the first state.

5. The information processing apparatus according to claim 1,

wherein the transmission unit sets a first bit to the packet to notify other processing unit of the first state.

6. The information processing apparatus according to claim 1,

wherein the first bit is set to a packet having a third bit indicating that the packet is valid.

7. The information processing apparatus according to claim 4,

wherein the detection unit detects that the second processing unit is in the first state based on the first bit, which is generated by the second processing unit and attached to the packet.

8. The information processing apparatus according to claim 4,

wherein, when the first processing unit is about to become a second state in which the first processing unit processes information, the transmission unit sets a second bit indicating that the first processing unit is in the second state.

9. The information processing apparatus according to claim 1, further comprising a retaining unit configured to retain a first identification (ID) unique to each processing unit and a discrimination unit configured to discriminate a packet transmitted by the each processing unit,

wherein the transmission unit transmits a packet to which data processed by the first processing unit and the first ID are attached, and

wherein the discrimination unit compares a second ID attached to a packet acquired from the ring bus with the first ID and discriminates the packet generated by the each unit.

10. The information processing apparatus according to claim 1, further comprising a timer configured to measure a predetermined time,

wherein, when the first bit is detected, the control unit restricts a new packet from being output during the predetermined time.

11. The information processing apparatus according to claim 9,

wherein the timer measures a period taken for a circulation of a packet in the ring bus and, when the first bit is detected, the control unit restricts a new packet from being output during a time acquired by integer multiplying the time taken for a circulation of a packet in the ring bus.

12. The information processing apparatus according to claim 1, further comprising a timer configured to measure a predetermined period and a register configured to retain an initial value “

TB”

of an output restriction time and an increased time “

TI”

thereof and a decreased time “

TD”

thereof,

wherein the control unit performs restriction and control based on a time calculated using the initial value “

TB”

, the increased time “

TI”

, and the decreased time “

TD”

.

13. The information processing apparatus according to claim 1,

wherein the packet includes a data packet and a command packet, and the processing unit processes data acquired from the data packet according to a command acquired from the command packet.

14. An information processing apparatus including a plurality of processing units communicably connected to a ring bus and configured to process information in order, and a first processing unit, which is one of the plurality of processing units, the apparatus comprising:

a transmission unit configured to, when the first processing unit is in a first state where the first processing unit does not process information acquired from the ring bus, transmit to the ring bus a packet indicating that the first processing unit is in the first state.

15. An information processing apparatus including a plurality of processing units communicably connected to a ring bus and configured to process information in order, and a first processing unit, which is one of the plurality of processing units, the apparatus comprising:

a detection unit configured to detect that a second processing unit, which is one of the plurality of processing units, is in the first state from a packet flowing in the ring bus; and

a control unit configured to, when the second processing unit is detected to be in the first state, restrict a packet having data processed by the first processing unit from being output to the ring bus.

16. An information processing apparatus including a plurality of processing units communicably connected to a ring bus and configured to process information in order, and a first processing unit, which is one of the plurality of processing units, the apparatus comprising:

a transmission unit configured to, when the first processing unit is in a first state where the first processing unit does not process information acquired from the ring bus, transmit to the ring bus a packet indicating that the first processing unit is in the first state;

a detection unit configured to detect that a second processing unit, which is one of the plurality of processing units, is in the first state from a packet flowing in the ring bus; and

a control unit configured to, when the second processing unit is detected to be in the first state, restrict data processed by the first processing unit from being output to the ring bus.

17. A computer readable storage medium storing a program causing each of a plurality of processing units communicably connected to a ring bus to execute a method, the method comprising:

transmitting to, when the each processing unit is in a first state where the processing unit does not process information acquired from the ring bus, the ring bus a packet indicating that the each processing unit is in the first state;

detecting that other processing unit is in the first state from a packet flowing in the ring bus; and

restricting, when the other processing unit is detected to be in the first state, a packet having data processed by the each processing unit from being output to the ring bus.

18. An information processing method executed by each of a plurality of processing units communicably connected to a ring bus, the method comprising:

transmitting to, when the each processing unit is in a first state where the processing unit does not process information acquired from the ring bus, the ring bus a packet indicating that the each processing unit is in the first state;

detecting that other processing unit is in the first state from a packet flowing in the ring bus; and

restricting, when the other processing unit is detected to be in the first state, a packet having data processed by the each processing unit from being output to the ring bus.