JP6578824B2 - Image forming apparatus, task control method and task control program in the same - Google Patents

Description

  The present invention relates to an image forming apparatus such as an MFP (Multi Function Peripheral) which is a multi-function digital multi-function peripheral having a plurality of functions such as a copy function, a printer function, a facsimile function, and a scan function, a task control method in the same apparatus, and It relates to a task control program.

  The power-saving technology called “big.LITTLE” developed by ARM Co., Ltd. has a first multi-core CPU having a plurality of cores as a basic configuration and high power consumption but high processing performance. A second multi-core CPU having a plurality of cores paired with each core of the multi-core CPU and having relatively lower power consumption and lower processing performance than the first multi-core CPU is referred to as an SoC (System- On-a-Chip) is mounted on one semiconductor chip.

  As one of the operation models for implementing such power saving technology, there is a multiprocessing model in which all the cores of the first and second multicore CPUs are always ON, and in particular, a software model called GTS (Global Task Scheduling) It is considered that this model is applied to the image forming apparatus such as the MFP described above.

  Here, the GTS model is such that the scheduler of the operating system distributes tasks for all the cores of the first multi-core CPU and the second multi-core CPU according to the load. Specifically, a CPU that is loaded when a task is moved between the core of the first multi-core CPU and the core of the second multi-core CPU according to the task load, and the operation of the task is resumed from the task execution history As a result, it is possible to achieve both processing performance and energy saving.

  However, when such a model is directly applied to an MFP or the like, the following situation occurs due to the processing characteristics of the MFP.

  That is, for example, two cores 0 and 1 are allocated for execution of RIP (Raster Image Processor) processing for developing data described in PostScript which is a page description language into bitmap data that can be printed or displayed. The RIP process is divided into a first RIP process and a second RIP process and is performed in band units, and the first RIP process for the first half data is performed by one core 0 and the second RIP process for the second half data is performed. When the RIP process is divided and processed by the core 1 and control is performed to synchronize and move to the next band process, for example, the load is biased to the core 0 on which the task of the first RIP process is executed In such a system situation, there is a difference in processing time between the core 0 and the core 1. For this reason, even if one of the cores has finished processing, it is difficult to say that the CPU performance is sufficiently utilized for the RIP processing by waiting for the other core to complete the processing.

  When such a situation occurs on the second multi-core CPU, in the above-described multi-processing model, if the load on the core 0 of the second multi-core CPU is increased and the processing is heavy, the process is executed on the core 0. Any or all of the tasks including the first RIP processing task that is being performed are to be migrated to the first multi-core CPU side.

  However, when the task of the first RIP process is shifted to the first multi-core CPU, the task of the second RIP process that needs to be synchronized with the task of the first RIP process remains in the core of the second multi-core CPU. Since there is a difference in the processing capability of the cores in which each task operates, the synchronization wait is not canceled after the next band.

  On the other hand, in the first multi-core CPU with high power consumption but high processing capability, when the task of the first RIP processing and the task of the second RIP processing that require synchronization are operating on different cores, When the load on one core is lightened, the task may be transferred to the second multi-core CPU in order to reduce power consumption. Also in this case, when only one task of the first RIP processing task or the second RIP processing task operating in the core is transferred to the second multi-core CPU, the first multi-core CPU is transferred to the other multi-core CPU. Therefore, there is a problem that the waiting for synchronization occurs due to a difference in the processing capability of the core on which each task operates, and the waiting for synchronization cannot be resolved.

  In Patent Document 1, when the process time limit is expected to be exceeded, the process that the system load monitoring unit causes is not caused to exceed the process to which the own process belongs and the time limit of all processes operating in the system does not occur. A technique for dividing into numbers is disclosed.

JP 2013-36553 A

  However, the technique described in Patent Document 1 is not a technique for solving a problem when a plurality of tasks having a synchronous relationship are assigned to different cores. For this reason, the processing target data is divided into the first task and the second task by a plurality of cores in either the first multi-core CPU or the second multi-core CPU, and the next processing is performed in synchronization. In the case of performing control such as shifting to the first multi-core CPU, the first task that occurs when the first task executed on the core is shifted to the other multi-core CPU because the load on one of the cores fluctuates. The problem that the waiting for synchronization between the second tasks cannot be resolved cannot be solved by the technique described in Patent Document 1.

  The present invention has been made in view of such a technical background. Processing data is divided into a first task and a second task by a plurality of cores, and the following are performed in synchronization. In the case of performing control that shifts to processing, the load caused by the task of one core fluctuates, so that the first task that has been performed in that core shifts to the other multi-core CPU. It is an object of the present invention to provide an image forming apparatus capable of eliminating the waiting for synchronization between one task and a second task, a task control method and a task control program in the apparatus.

The above problem is solved by the following means.
(1) a first multi-core CPU having a plurality of cores;
A second multi-core CPU that is mounted on the same chip as the first multi-core CPU, has a plurality of cores, consumes relatively less power, and has a relatively lower processing performance than the first multi-core CPU. If, based on the operating system, and task transition control means for controlling to shift the task between the first multi-core CPU and said second multi-core CPU, based on the operating system, and the first multi-core CPU the Based on the load monitoring means for monitoring the load due to the task of each core in the second multi-core CPU, the load monitored by the load monitoring means and a preset threshold value, the task of any core is assigned to the other Task migration determination means for determining whether to migrate to the core of a multi-core CPU, and the task migration When the determination means determines that the task is to be transferred to the core of the other multi-core CPU, the first task to be transferred is a second task operating on another core in the same multi-core CPU; Task synchronization relationship determination means for determining whether or not they are in a synchronization relationship, and the task synchronization relationship determination means determines that the first task that has been transferred is in synchronization with the second task. If it is, the task transition control means, said first task and the first or implementing the transition control to shift the third task running on the same core, or said first task the An image forming apparatus that performs a second shift control for shifting both of the second tasks.
(2) the said first task in the synchronous relationship second task, an image forming apparatus according to item 1, which is the first RIP processing task and the second RIP processing task to implement the RIP processing.
(3) The first RIP processing task performs RIP processing of the first half of data in processing units, and the second RIP processing task executes RIP processing of the second half of data in processing units. Image forming apparatus.
(4) the first RIP processing task and the second RIP processing task takes the synchronization completion of the first RIP processing and the second RIP processing, the following processing image data that combines the respective processing results 4. The image forming apparatus according to item 3, which is transferred to
(5) the first task and the second task in the synchronization relationship, the image forming according to item 1, which is the first image conversion processing task and the second image conversion processing task of implementing the image conversion process apparatus.
(6) The first image conversion processing task performs an image conversion process for half of the image data in the processing unit, and the second image conversion processing task performs an image conversion process for the other half of the data in the processing unit. 6. The image forming apparatus according to item 5 above.
(7) said first image conversion processing task and the second image conversion processing task takes a synchronization first image conversion process and the completion of the second image conversion process, and combines the respective processing result image 7. The image forming apparatus according to item 6, wherein data is transferred to a data storage area.
(8) the first task and the second task is performed at the core of the second multi-core CPU, the task transition control means can perform both the first transition control and the second transition control In addition, even when the first task is dominant in the core in which the first task is executed and the third task is transferred to the first multi-core CPU, the load on the core is 8. The image forming apparatus according to any one of the preceding items 1 and 7, which performs the second transition control when it is determined that it is not reduced.
(9) the first task and the second task is performed at the core of the second multi-core CPU, the task transition control means can perform both the first transition control and the second transition control Whether the power consumption priority mode or the processing time priority mode is determined. If the power consumption priority mode is selected, the first transition control is performed. If the processing time priority mode is selected, the second transition control is performed. 9. The image forming apparatus according to any one of 1 and 8 above.
(10) A first multi-core CPU having a plurality of cores, mounted on the same chip as the first multi-core CPU, and having a plurality of cores, and consumes more power than the first multi-core CPU. to reduce the processing performance and relatively low second multi-core CPU, an image forming apparatus having a, based on the operating system, transition tasks between the first multi-core CPU and said second multi-core CPU and task transition control step of performing control to, based on the operating system, and load monitoring method comprising: monitoring the load of each core task in the first multi-core CPU the second multi-core CPU, it is monitored by the load monitoring step Based on the load and the preset threshold, the task of one core is assigned to the other The task transition determination step for determining whether or not to shift to the core of the multi-core CPU, and the task transition determination step determines that the task is to be transferred to the core of the other multi-core CPU. A task synchronization relationship determining step for determining whether or not the task is synchronized with a second task operating on another core in the same multi-core CPU, and the task synchronization relationship determining step shifts When it is determined that the target first task is in a synchronous relationship with the second task, the task migration control step includes a third task operating on the same core as the first task. or carrying out the first transition control to shift the tasks or second transition system for shifting both said first task a second task Task control method in an image forming apparatus which comprises carrying out the.
(11) A first multi-core CPU having a plurality of cores, mounted on the same chip as the first multi-core CPU, and having a plurality of cores, and consumes more power than the first multi-core CPU. the CPU of the image forming apparatus including the manner small performance relatively low second multi-core CPU, and based on the operating system, the task between said first multi-core CPU the second multi-core CPU and task transition control step for controlling to shift the on the basis of the operating system, and load monitoring step of monitoring the load of each core task in said first multi-core CPU second multi-core CPU, by the load monitoring step Any core task based on monitored load and preset threshold The task transition determination step for determining whether or not to shift to the core of the other multi-core CPU and the task shift determination step are determined to be transferred to the core of the other multi-core CPU. A task synchronization relationship determining step for determining whether or not the first task is synchronized with a second task operating on another core in the same multi-core CPU, and the task synchronization relationship determining step When it is determined that the first task to be migrated is in a synchronous relationship with the second task, the task migration control step includes the first task operating on the same core as the first task. first either by carrying out the transition control to shift the 3 tasks or shifts both the said first task a second task Task control program for implementing the second migration control.

  According to the invention described in (1) above, when it is determined that the task is to be transferred to the core of the other multi-core CPU, the first task to be transferred operates on another core in the same multi-core CPU. It is determined whether or not the second task is in a synchronous relationship, and if it is determined that the second task is in a synchronous relationship, the first task is transferred to the third task operating on the same core as the first task. Or a second transition control that shifts both the first task and the second task. Therefore, when the first transition control is performed, the first task and the second task that are in a synchronous relationship are performed by the core in the same multi-CPU, and the first core is shifted by the third core. Since the load on the core executing the task is reduced and there is no difference in the core capabilities, the difference in processing time between the first task and the second task can be eliminated, and the synchronization wait can be eliminated.

  On the other hand, when the second transition control is performed, since both the first task and the second task that are in a synchronous relationship are transferred to the core of the other multi-core CPU, the first task and the second task The difference in processing time between tasks can also be eliminated, and synchronization waiting can be eliminated.

  According to the invention described in the preceding item (2), when the RIP processing task is divided into two and synchronized, the waiting for synchronization can be eliminated.

  According to the invention described in item (3) above, when the RIP process for the first half of the data in the processing unit and the RIP process for the second half are performed in synchronization with different cores, the synchronization wait can be eliminated.

  According to the invention described in the preceding item (4), when the completion of the first RIP process and the second RIP process is synchronized, and the image data obtained by combining the respective process results is transferred to the next process, the synchronization is performed. You can eliminate the wait.

  According to the invention described in item (5), when the image conversion processing task is divided into two and synchronized, the waiting for synchronization can be eliminated.

  According to the invention described in the preceding item (6), when the image conversion process of half of the image data of the processing unit and the image conversion process of the other half are performed in synchronization with different cores, the synchronization waiting can be eliminated.

  According to the invention described in (7) above, when the completion of the first image conversion process and the second image conversion process is synchronized, and the image data obtained by combining the respective process results is transferred to the data storage area In addition, the synchronization wait can be eliminated.

  According to the invention described in (8) above, even when the first task is dominant in the core in which the first task is executed and the third task is shifted to the first multi-core CPU, When it is determined that the load on the core is not reduced, since the second transition control for shifting both the first task and the second task to the first multi-core CPU is performed, the synchronization wait can be reliably eliminated. .

  According to the invention described in the preceding item (9), it is determined whether the power consumption priority mode or the processing time priority mode. In the power consumption priority mode, the first transition control is performed and only the third task is the first. Therefore, the synchronization waiting time can be shortened while suppressing power consumption. On the other hand, in the processing time priority mode, the second transition control is performed, and both the first task and the second task are transferred to the first multi-core CPU. Can be resolved.

  According to the invention described in the preceding item (10), since the first transition control or the second transition control is performed, the waiting for synchronization can be eliminated.

  According to the invention described in the preceding item (11), the CPU of the image forming apparatus can be caused to execute a process capable of eliminating the waiting for synchronization by the first transition control or the second transition control.

1 is a block diagram illustrating a configuration of an image forming apparatus 1 according to an embodiment of the present invention. (A)-(C) is a figure for demonstrating the structure and basic operation | movement of CPU. (A) And (B) is a figure for demonstrating the condition where waiting for a synchronization generate | occur | produces. It is explanatory drawing about the process for canceling | requiring a synchronization wait. It is a figure for demonstrating the other process for canceling | requiring a synchronization wait. It is a functional block diagram of CPU. It is a flowchart which shows the transfer control process of a task. It is a flowchart which shows the content of the task transfer determination process of step S04 of FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an image forming apparatus 1 according to an embodiment of the present invention. In this embodiment, as the image forming apparatus 1, the MFP that is the above-described multifunction digital multi-function peripheral is used. Hereinafter, the image forming apparatus is also referred to as an MFP.

  The image forming apparatus 1 includes a ROM 12, a RAM 13, a scanner unit 14, a storage unit 15, a printer unit 16, an operation panel 17, a network interface (network I / F) 18, a USB interface (USB I / F) 19, an image processing ASIC 20, and the like. These are connected to the CPU 11 via a bus.

  The CPU 11 controls the entire image forming apparatus 1 and controls basic functions such as a copy function, a printer function, a scan function, and a facsimile function. The CPU 11 includes a task migration control unit 111 and a load monitoring unit 112 that are functionally configured by executing an OS (operating system), and tasks that are functionally configured by executing an application (MFP application). A migration determination unit 113 and a task synchronization relationship determination unit 114 are provided. These will be described later.

  The ROM 12 is a memory for storing an operation program of the CPU 11 and the like.

  The RAM 13 is a memory that provides a work area when the CPU 11 operates based on an operation program.

  The scanner unit 14 is a reading unit that reads an image of a document placed on a document table (not shown) and outputs image data.

  The storage unit 15 is configured by a non-volatile storage device such as a hard disk drive (HDD), and stores an OS, an MFP application, image data of a document scanned by the scanner unit 14, and the like.

  The printer unit 16 prints image data of a document scanned by the scanner unit 14 and external print data in accordance with an instructed mode.

  The operation panel 17 is used for various input operations and the like, and is provided with a display unit 171 composed of a touch panel type liquid crystal or the like for displaying a message or an operation screen, and an operation provided with a numeric keypad, a start key, a stop key, and the like. A portion 172 is provided.

  The network I / F 18 transmits and receives data by controlling communication with other image forming apparatuses on the network and other external devices such as user terminals.

  The USB I / F 19 is a connection unit for connecting a USB memory (not shown), and the image processing ASIC (Application Specific Integrated Circuit) 20 is a circuit that performs image processing.

  As shown in FIG. 2A, the CPU 11 includes a first multi-core CPU (also referred to as a big cluster) 115 and a second multi-core CPU (also referred to as a LITTLE cluster) 116 as one SoC. It is mounted on the chip. The first multi-core CPU 115 is a CPU with high power consumption but high processing capability, and the second multi-core CPU 116 is a CPU with low power consumption but relatively low power consumption compared to the first CPU 115.

  The first multi-core CPU 115 includes four cores (also referred to as big cores) 115a to 115d, and the second multi-core CPU 116 is paired with each core 115a to 115d of the first multi-core CPU 115. Each core (also referred to as a LITTLE core) 116a to 116d. In this embodiment, a multi-processing model in which all the cores of the multi-core CPUs 115 and 116 are turned on is applied. In particular, the OS scheduler has all the cores of the first multi-core CPU 115 and the second multi-core CPU 116 depending on the load. The above-mentioned GTS for distributing tasks to the target is applied.

  In the multiprocessing model, the number of cores visible from the OS is eight as shown in FIG. In this embodiment, each task is first assigned to the cores 116a to 116d of the second multi-core CPU 116 with low processing performance but low power consumption. For example, the load on the core 116a of the second multi-core CPU 116 However, when a preset threshold value is reached, some or all of the tasks operating on the core 116a are transferred to the core 115a of the first multi-core CPU 115 or the like based on the OS.

  FIG. 2A shows a state in which a plurality of tasks are assigned to the cores 116 a to 116 d of the second multi-core CPU 116. The core 116a is assigned a print control task (denoted “print”), the core 116b is assigned a scan control task (denoted “scan”), and the core 116d is assigned an interrupt processing task (“interrupt”). ") Is assigned.

  Also, some tasks may be configured to start with multiple cores even if the task is the same, and perform processing while synchronizing at regular intervals, for the purpose of ensuring processing speed. . In this embodiment, for RIP processing tasks for expanding data described in PostScript, which is a page description language, into bitmap data that can be printed and displayed, tasks are assigned across the cores 116a and 116b. . Specifically, a task called a first RIP processing task (RIP processing task 1) is generated in the core 116a, and a second RIP processing task (RIP processing task 2) is generated in the core 116b. The RIP processing task 1 of the core 116a and the RIP processing task 2 of the core 116b separately process the first half and the RIP processing 1 by the RIP processing task 1 and the RIP processing 2 by the RIP processing task 2, respectively. When the upper module determines that all the processes are completed, the data obtained by combining the processing results is transferred to the next process, and the RIP process for the next band data is performed.

  Furthermore, in this embodiment, an image conversion processing task for converting scanned image data into another format such as PDF or JPEG is also assigned across the cores 116c and 116d. Specifically, a task called a first image conversion processing task (image conversion processing task 1) is generated in the core 116c, and a second image conversion processing task (image conversion processing task 2) is generated in the core 116d. The image conversion processing task 1 of the core 116c and the image conversion processing task 2 of the core 116d separately process the other half, and the image conversion processing task 1 and the image conversion processing task 2 are performed separately. When the upper module determines that all the processes are completed, the image data obtained by combining the respective processing results is stored in the storage unit 15 or the like, which is a data storage area, and the next image is processed. Perform image conversion processing of data.

  In FIG. 2A, the RIP processing task 1 shares the print control task and the core 116a, and the RIP processing task 2 shares the scan control task and the core 116b. When a scan job is input, as shown in FIG. 2A, the scan control task and image conversion processing tasks 1 and 2 operate, but the RIP processing tasks 1 and 2 and the print control task operate. Not. In FIG. 2, the task that is operating is hatched.

  When a print job (PC print job) is input from a personal computer or the like, the RIP processing tasks 1 and 2 and the print control task operate as shown in FIG. 2B, but the scan control task does not operate. As a load, the core 116a side becomes high.

  If this situation continues, there will be a difference in the processing progress between the core 116a and the core 116b, the processing in both cores will be completed, the processing results will be combined, transferred to the next processing, and transferred to the next band processing. There will be a wait.

  This situation will be described with reference to FIG. As shown in FIG. 3A, in the core 116a of the second multi-core CPU 116, R111, R112, and R113, which are band data of the first half of two band data as processing units, are processed by the RIP processing task 1. RIP processed. However, the print process for the data P11 by the print control task is performed between the RIP processes of the data R111 and R112, and the print process for the data P12 by the print control task is performed between the RIP processes of the data R112 and R113.

  On the other hand, in the core 116b, the RIP processing of R21 which is band data of the latter half is performed, but since only the RIP processing task 2 operates in the core 116b, the processing is continuously performed, and the RIP in the core 116b is performed. The process ends earlier than the RIP process in the core 116a.

  Then, in synchronization with the timing T1 of completion of the RIP process in the core 116a, the data subjected to the RIP process in both cores is combined and transferred to the next process. After completion of the RIP process in the core 116a, the core 116a starts the RIP process for the next band data (R121, R122, and R123), and the core 116b starts the RIP process for the next band data (R22). .

  Thus, since the completion of the RIP processing in the core 116a is later than the completion of the RIP processing in the core 116b, the completion timing T1 of the RIP processing in the core 116a after the completion of the RIP processing in the core 116b. Until this time, the synchronization wait of time S1 occurs. Similarly, in the next band data processing, a synchronization wait occurs, and a synchronization wait occurs every time the band data is RIP processed.

  The load due to the task of each core is monitored, and if it is determined that the load due to the task of the core 116a has reached a preset threshold value, a part or all of the tasks of the core 116a are controlled by GTS control. 1 is transferred to the core of the multi-core CPU 115.

  Here, it is assumed that the RIP processing task 1 of the core 116a is transferred to the core 115a of the first multi-core CPU 115 at the timing T2 when the processing of the data R112 is completed as shown in FIG. 3B by the conventional GTS control. . In the core 115a of the first multi-core CPU 115, the RIP processing 1 of the remaining data R113 is completed at timing T3. On the other hand, the RIP process 2 in the core 116b of the second multi-core CPU 116 has already been completed, and the synchronization wait of time S3 occurs until the RIP process of the data R113 is completed in the core 115a of the first multi-core CPU 15. However, the synchronization waiting time S3 is shorter than the waiting time S1 before task transition. In synchronization with the completion of the RIP processing in the core 115a, the data RIP processed in the core 116b and the data RIP processed in the core 115a are combined and transferred to the next processing.

  After completion of the RIP processing for the data R113, RIP processing 1 is performed by the core 115a of the first multi-core CPU 115 and RIP processing 2 is performed by the core 116b of the second multi-core CPU 116 for each of the next band data. Since the first multi-core CPU 115 is superior in processing performance to the second multi-core CPU 116, before the completion of the RIP processing in the core 116b of the second multi-core CPU 116, the first multi-core CPU 115 in the core 115a of the first multi-core CPU 115 The RIP process is completed early, and a motivation wait of time S4 occurs until the process completion timing T4 in the core 116b. Furthermore, the next band data is similarly subjected to the synchronization wait, and the synchronization wait occurs every time the band data is RIP processed.

  That is, even if the RIP processing task 1 in the core 116a of the second multi-core CPU 116 is transferred to the core 115a of the first multi-core CPU 115, a synchronization wait still occurs, and the RIP processing task 1 and the RIP processing task 2 It is not possible to eliminate the synchronization wait that occurs between the two.

  Therefore, in this embodiment, when the RIP processing task 1 of the core 116a in the second multi-core CPU 116 to be transferred is transferred to the core 115a in the first multi-core CPU 115, the RIP processing task 1 and the second multi-core It is determined whether tasks operating in other cores of the CPU 116 are in a synchronous relationship. In this embodiment, the RIP processing task 2 operating in the other core 116 b is in a synchronous relationship with the RIP processing task 1.

  Therefore, if there is a synchronous relationship, the print control task, which is another task operating on the same core 116a as the RIP processing task 1, is transferred to the core of the first multi-core CPU 115 as shown in FIG. The process proceeds to 115a.

  FIG. 4B shows the processing when the print control task is transferred to the core 115a of the first multi-core CPU 115. Note that FIG. 4A shows a state before the transition, and shows the same state as FIG.

  As shown in FIG. 4B, it is assumed that the print control task is transferred to the core 115a of the first multicore CPU 115 at the timing T2 when the RIP processing of the data R112 in the core 116a in the second multicore CPU 116 is completed. The core 116a executes RIP processing of the remaining data R113 immediately after processing of the data R112, and is completed at timing T5. On the other hand, the RIP processing of the core 116b of the second multi-core CPU 116 has already been completed, and a synchronization wait of time S5 occurs until the RIP processing of the data R113 in the core 116a is completed. However, the synchronization waiting time S5 is shorter than the synchronization waiting time S1 before task transfer. In synchronization with the completion of the RIP process in the core 116a, the band data subjected to the RIP process in the core 116b and the band data subjected to the RIP process in the core 116a are combined and transferred to the next process.

  After the processing of the data R113 is completed, RIP processing is performed on the next band data by the core 116a and the core 116b of the second multi-core CPU 116, respectively. Since the print control task operating in the core 116b has shifted to the core 115a of the first multi-core CPU 115, the tasks operating in the cores 116a and 116b are only the RIP processing task 1 and the RIP processing task 2, respectively. . For this reason, the RIP process by each task is completed almost simultaneously at the timing T6, and the waiting for synchronization is eliminated. Similarly, no synchronization wait occurs for the next band data and subsequent band data.

  In this way, the print control task operating on the same core 116a as the RIP processing task 1 is transferred to the core 115a of the first multi-core CPU 115, so that the processing time difference between the RIP processing task 1 and the RIP processing task 2 is increased. That is, the synchronization waiting can be almost eliminated, and the processing efficiency is improved.

  In addition to the RIP processing task 1 and the print control task in the core 116a, when a single task that is not synchronized with a task operating in another core is operating, either or both of the task and the print control task. One of them may be transferred to the core 115a of the first multi-core CPU 115.

  In this embodiment, the print control task that operates on the same core 116a as the RIP processing task 1 is transferred without transferring the RIP processing task 1 that is synchronized with the RIP processing task 2 that operates on the other core 116b. However, as shown in FIG. 5, the tasks in synchronization relation, that is, both the RIP processing task 1 and the RIP processing task 2 are moved to the corresponding tasks 115a and 115b of the first multi-core CPU 115. Also good. By doing so, the difference in processing time between the RIP processing task 1 and the RIP processing task 2 can be eliminated, and synchronization waiting can be eliminated.

  Note that the transfer of both the RIP processing task 1 and the RIP processing task 2 to the first multi-core CPU 115 is because the load on the core 116a by the RIP processing task 1 is more dominant than the other print control tasks. Even when the task is transferred to the first multi-core CPU 115, it is particularly effective when it is determined that the load on the core 116a is not reduced. By migrating both the RIP processing task 1 and the RIP processing task 2, the load on the core 116a can be reliably reduced.

  Further, when the RIP processing task 1 and RIP processing task 2 are compared with the print control task, the RIP processing task 1 and the RIP processing task 2 have a larger load than the print control task, and the processing takes time. On the other hand, as described above, the first multi-core CPU 115 has high power consumption but high processing capability, and the second multi-core CPU 116 has lower power consumption than the first CPU 115 but relatively low processing capability. .

  Therefore, it is determined whether the image forming apparatus 1 is in the power consumption priority mode or the processing time priority mode. If the image forming apparatus 1 is in the power consumption priority mode, the print control task is transferred to the first multi-core CPU 115. It is desirable to transfer task 1 and RIP processing task 2 to the first multi-core CPU 115. Whether the image forming apparatus 1 is in the power consumption priority mode or the processing time priority mode may be determined by a user setting or the like, based on the system speed of the image forming apparatus 1 and in the case of a low-speed machine. In the case of the power priority mode and the high-speed machine, the processing time priority mode may be determined.

  FIG. 6 shows a functional block diagram of the CPU 11. As described above, the CPU 11 has a task transition control unit 111 and a load monitoring unit 112 that are functionally configured by executing the OS, a task transition determination unit 113 that is functionally configured by executing the MFP application, and A task synchronization relationship determination unit 114 is provided.

  The task migration control unit 111 performs migration control when the task migration determination unit 113 determines that the task is migrated to the core of the other multi-core CPU. In particular, in this embodiment, the first transition control for shifting the print control task is performed or both of the RIP processing task 1 and the RIP processing task 2 are shifted according to the determination result by the task synchronization relationship determination unit 114. The second transition control is performed.

  The load monitoring unit 112 monitors the load caused by each core task in the first multi-core CPU 115 and the second multi-core CPU 116.

  Based on the core load monitored by the load monitoring unit 112 and a preset threshold value, the task migration determining unit 113 migrates the core task whose load has reached the threshold value to the core of the other multi-core CPU. Determine if. In this embodiment, it is determined that the task of the core 116a is transferred to the first multi-core CPU 115 when the load of the monitored core 116a reaches a preset threshold value.

  The task synchronization relationship determination unit 114, when the task migration determination unit 113 determines that the task is to be migrated to the core of the other multi-core CPU, is the first task to be migrated (in this embodiment, the RIP processing task) It is determined whether 1) is synchronized with a task operating in another core (a core other than the core 116a in this embodiment) in the same multi-core CPU (in this embodiment, the second multi-core CPU 116).

  If it is determined that they are in a synchronous relationship, the print control task is transferred to the first multi-core CPU 115 as described above, or both the RIP processing task 1 and the RIP processing task 2 that are in a synchronous relationship are transferred. Let

  FIG. 7 is a flowchart showing task migration control processing. This process is executed by the CPU 11 operating according to the OS and the MFP application.

  In this embodiment, each task operates on the core of the second multi-core CPU 116. In addition, when it is determined that the first task to be transferred is in a synchronous relationship with the second task operating on another core, the image forming apparatus 1 uses the same core as the first task. Having a function capable of performing both the first transition control for shifting the operating third task and the second transition control for shifting both the first task and the second task; To do.

  In step S01, the load due to each core task of the second multi-core CPU 116 is monitored, and in step S02, it is determined whether or not the first task that is the migration target task exists when the core load reaches the threshold value. To do. If the load does not reach the threshold value and there is no migration target task (NO in step S02), the process returns to step S01. If there is a task to be migrated (YES in step S02), the process proceeds to step S03.

  In step S <b> 03, it is determined whether or not the first task is in a synchronous relationship with a second task that is another task that operates in another core of the second multi-core CPU 116.

  If there is a synchronization relationship (YES in step S03), it is determined in step S04 whether to perform the first transition control or the second transition control by the task transition determination process.

  When the first transition control is performed, the process proceeds to step S06, the third task operating on the same core as the first task is shifted to the corresponding core of the first multi-core CPU 115, and then the process returns to step S01. . When performing the second transition control, the process proceeds to step S07, and both the first task and the second task synchronized with the first task are migrated to the corresponding core of the first multi-core CPU 115. After that, the process returns to step S01.

  If the first task is not synchronized with the second task in step S03 (NO in step S03), task transition control is performed by normal control by the OS in step S05, and the process returns to step S01.

  FIG. 8 is a flowchart showing the contents of the task migration determination process in step S04 of FIG.

  In step S041, it is determined whether the load on the core is not reduced even when the first task is dominant on the core and the third task is transferred. If it is not dominant (NO in step S041), in step S042, the image forming apparatus 1 determines whether it is in the power consumption priority mode or the processing time priority mode. In the case of the power consumption priority mode, the process proceeds to step S06 as the first transition determination control.

  If the first task is dominant on the core in step S041 (YES in step S041), and if the image forming apparatus 1 is in the processing time priority mode in step S042, the second transition determination control is performed. Proceed to certain step S07.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

  For example, the embodiment has been described in which the task is transferred to the first multi-core CPU 115 when the load on the core by the task operating in the core of the second multi-core CPU 116 reaches a threshold value. A configuration may be adopted in which the task is transferred to the second multi-core CPU 116 when the load on the core due to the task operating in the core decreases to a threshold value. In this case as well, tasks other than tasks in a synchronous relationship may be transferred to the second multi-core CPU 116, or tasks in a synchronous relationship may be transferred.

  Further, when the image forming apparatus 1 determines that the first task to be transferred is in synchronization with the second task operating on another core, the image forming apparatus 1 uses the same core as the first task. It is assumed that it has a function capable of performing both the first transition control for shifting the operating third task and the second transition control for shifting both the first task and the second task. As described above, the image forming apparatus may perform only one of the first transition control and the second transition control.

  Further, the case where the task having the synchronization relationship is the RIP processing task has been described. However, even when the task having the synchronization relationship is the image conversion processing task described above, the same control as in the case of the RIP processing task can be performed. it can.

1 Image forming apparatus 11 CPU
12 ROM
13 RAM
DESCRIPTION OF SYMBOLS 14 Scanner part 15 Memory | storage part 17 Operation part 111 Task transfer control part 112 Load monitoring part 113 Task transfer determination part 114 Task synchronous relationship determination part

Claims (11)

A first multi-core CPU having a plurality of cores;
A second multi-core CPU that is mounted on the same chip as the first multi-core CPU, has a plurality of cores, consumes relatively less power, and has a relatively lower processing performance than the first multi-core CPU. When,
Based on the operating system, and task transition control means for controlling to shift the task between the first multi-core CPU and said second multi-core CPU,
Based on the operating system, and load monitoring means for monitoring the load of each core task in said first multi-core CPU second multi-core CPU,
Based on the load monitored by the load monitoring means and a preset threshold, task transition determination means for determining whether to transfer the task of any core to the core of the other multi-core CPU;
When the task transition determination means determines that the task is to be transferred to the core of the other multi-core CPU, the first task that is the transfer target is operating on another core in the same multi-core CPU. Task synchronization relationship determining means for determining whether or not the task is in a synchronized relationship;
With
When it is determined by the task synchronization relationship determination means that the first task to be transferred is in synchronization with the second task, the task transfer control means is the same as the first task. first or implementing the transition control to shift the third task running on the core, or to implement the second transition control to shift both said first task and said second task An image forming apparatus. Wherein the first task in the synchronous relationship second task, an image forming apparatus according to claim 1 which is the first RIP processing task and the second RIP processing task to implement the RIP processing. 3. The image according to claim 2, wherein the first RIP processing task performs RIP processing of a first half part of processing unit data, and the second RIP processing task performs RIP processing of a second half part of processing unit data. Forming equipment. The first RIP processing task and the second RIP processing task, first take the synchronization RIP processing and completion of the second RIP processing, the transfer to the next process each processing result image data that combines the The image forming apparatus according to claim 3. The first task and the second task in the synchronization relationship, the image forming apparatus according to claim 1 which is the first image conversion processing task and the second image conversion processing task of implementing the image conversion processing.   The first image conversion processing task performs an image conversion process of half of the image data of the processing unit, and the second image conversion processing task executes an image conversion process of the other half of the data of the processing unit. The image forming apparatus according to 5. Said first image conversion processing task and the second image conversion processing task takes a synchronization first image conversion process and the completion of the second image conversion process, an image data obtained by combining the respective process result data The image forming apparatus according to claim 6, wherein the image forming apparatus transfers the image to the storage area. The first task and the second task is performed at the core of the second multi-core CPU,
The task transition control means is capable of performing both the first transition control and the second transition control, and the first task is dominant in a core where the first task is performed, 8. The second transition control is performed according to claim 1, wherein even when a third task is transferred to the first multi-core CPU, when it is determined that the load on the core is not reduced, the second shift control is performed. Image forming apparatus. The first task and the second task is performed at the core of the second multi-core CPU,
The task transition control means can perform both the first transition control and the second transition control, and determines whether it is a power consumption priority mode or a processing time priority mode. The image forming apparatus according to claim 1, wherein the first transition control is performed, and the second transition control is performed in the processing time priority mode. A first multi-core CPU having a plurality of cores;
A second multi-core CPU that is mounted on the same chip as the first multi-core CPU, has a plurality of cores, consumes relatively less power, and has a relatively lower processing performance than the first multi-core CPU. When,
An image forming apparatus comprising
Based on the operating system, a task transition control step for controlling to shift the task between the first multi-core CPU and said second multi-core CPU,
Based on the operating system, and load monitoring step of monitoring the load of each core task in the first multi-core CPU the second multi-core CPU,
A task transition determination step for determining whether to shift the task of any core to the core of the other multi-core CPU based on the load monitored by the load monitoring step and a preset threshold;
When it is determined in the task transition determination step that the task is to be transferred to the core of the other multi-core CPU, the first task that is the transfer target is operating on another core in the same multi-core CPU. A task synchronization relationship determination step for determining whether or not there is a synchronization relationship with the task,
Run
When it is determined by the task synchronization relationship determination step that the first task to be transferred is in synchronization with the second task, the task transfer control step is the same as the first task. first or implementing the transition control to shift the third task running on the core, or to implement the second transition control to shift both said first task and said second task A task control method in an image forming apparatus. A first multi-core CPU having a plurality of cores;
A second multi-core CPU that is mounted on the same chip as the first multi-core CPU, has a plurality of cores, consumes relatively less power, and has a relatively lower processing performance than the first multi-core CPU. When,
In the CPU of the image forming apparatus equipped with
Based on the operating system, a task transition control step for controlling to shift the task between the first multi-core CPU and said second multi-core CPU,
Based on the operating system, and load monitoring step of monitoring the load of each core task in the first multi-core CPU the second multi-core CPU,
A task transition determination step for determining whether to shift the task of any core to the core of the other multi-core CPU based on the load monitored by the load monitoring step and a preset threshold;
When it is determined in the task transition determination step that the task is to be transferred to the core of the other multi-core CPU, the first task that is the transfer target is operating on another core in the same multi-core CPU. A task synchronization relationship determination step for determining whether or not there is a synchronization relationship with the task,
And execute
When it is determined by the task synchronization relationship determination step that the first task to be transferred is in synchronization with the second task, the task transfer control step is the same as the first task. the first or the transition control is performed to shift the third task running on the core, or the first task and for causing executing the second transition control to shift both said second task Task control program.