JP6500707B2 - Image forming apparatus, task control method in the same apparatus, and task control program - Google Patents

Description

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

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

  As one of operation models implementing such power saving technology, there is a multi-processing model in which all cores of the first and second multi-core CPUs are always on, and above all, a software model called GTS (Global Task Scheduling) It is considered to apply this model to an image forming apparatus such as the MFP described above.

  Here, in the GTS model, a scheduler of the operating system distributes tasks targeting all cores of the first multi-core CPU and the second multi-core CPU according to the load. Specifically, according to the task load, move the task between the core of the first multi-core CPU and the core of the second multi-core CPU, and load the task when restarting the task operation from the execution history of the task Automatically, and as a result, both processing performance and energy saving can be achieved.

  However, when such a model is applied as it is to an MFP or the like, a situation occurs in which the characteristics of the multi-core CPU can not be sufficiently exhibited due to the processing characteristics of the MFP.

  That is, for example, in a scan job for transmitting image data obtained by scanning an image to a predetermined destination, processing for converting the image data into a file format designated by a user or the like is performed. For example, depending on the file format, such as the format called Compact PDF (referred to as CPDF: PDF: Portable Document Format), high-load processing may be performed, but when high-load processing is performed once After that, the scan job task will be assigned to the first multi-core CPU with high processing performance.

  However, in the case of JPEG (Joint Photographic Experts Group), TIFF (Tagged Image File Format), etc. where the file format does not require high-load conversion processing, it is not necessary to perform processing with the first multi-core CPU with high power consumption. Nevertheless, as a result of continuing the processing as it is, there was a problem that unnecessary power consumption occurred.

  Also, conversely, when the image conversion processing task is assigned to the core of the second multi-core CPU, and high-load image conversion processing is required, the task was promptly transferred to the first multi-core CPU Although the processing time is faster, there is also a problem that the task can not be transferred to the first multi-core CPU until the load reaches a preset threshold.

  In Patent Document 1, a cache memory is provided for each of a plurality of processors, and the cache status calculation unit calculates cache usage status such as the number of memory accesses and cache hit rate for each task, and the operation amount of a certain process If the threshold exceeds a predetermined threshold, the allocation management unit refers to the cache usage status and preferentially moves one of a plurality of tasks in the process with a smaller number of memory accesses or a higher cache hit rate. A multiprocessor system is disclosed that is selected as a target task and assigned to another processor that is processing a different process.

  Further, Patent Document 2 shows a multiprocessor system having first and second processors and task queues in which each of the processors holds a thread to be executed respectively. When the power consumption of the first processor among the plurality of processors exceeds the first threshold, the power consumption of the second processor other than the first processor is the first threshold. If the second threshold smaller than the second threshold is not exceeded, determination means for determining that it is necessary to move the thread, and the thread held in the task queue of the first processor is moved to the task queue of the second processor A multiprocessor system is disclosed which comprises a thread moving means.

WO 2010/093003 JP, 2010-39802, A

  However, the techniques described in Patent Document 1 and Patent Document 2 are techniques for moving a task when a predetermined threshold is exceeded, but since high-load processing is performed once, the processing performance is high in the subsequent processes. When a task is assigned to one multi-core CPU, processing continues in the first multi-core CPU with high power consumption even though the next job does not require high-load conversion processing. In contrast, it was not possible to provide a solution.

  The present invention has been made in view of such technical background, and a task is assigned to a first multi-core CPU, but high-load processing is not necessary, or a task is a second multi-core If tasks need to be transferred to the first multi-core CPU early because they are assigned to CPUs but require high-load processing, the tasks can be transferred from one multi-core CPU to the other multi-core CPU early It is an object of the present invention to provide an image forming apparatus capable of transitioning, a task control method in the same apparatus, and a task control program.

The above-mentioned subject is solved by the following means.
(1) A first multi-core CPU having a plurality of cores, and a plurality of cores are mounted on the same chip as the first multi-core CPU, and the power consumption is relatively higher than that of the first multi-core CPU A second multi-core CPU that is relatively small and has relatively low processing performance,
Based on an operating system, load monitoring means for monitoring a load due to a task in the first multi-core CPU and the second multi-core CPU, and based on a load monitored by the load monitoring means and a preset first threshold. Whether the task is to be transferred from the first multi-core CPU to the second multi-core CPU, or based on the load monitored by the load monitoring means and a preset second threshold value. A task transition determination unit that determines whether to shift from the second multi-core CPU to the first multi-core CPU; and the task transition determination unit determines that the task is to be migrated based on the operating system; Migrate tasks between one multi-core CPU and the second multi-core CPU Task transition control means for performing control, and at least one of the first threshold and the second threshold for a task activated by the first multicore CPU or the second multicore CPU, the processing time of the task And threshold power changing means for changing according to a preset change content based on the power consumption and the power consumption, and the task transition judging means changes the first threshold or the second threshold by the threshold changing means. In this case, it is determined whether to shift the task based on the load monitored by the load monitoring unit and the changed first threshold or second threshold.
(2) The image forming apparatus according to item 1, wherein the task transition determination unit specifies which of the first multicore CPU and the second multicore CPU is to be activated according to a load of a task.
(3) If the task is a task that is divided and executed by a plurality of cores of the second multi-core CPU, and the load of each core by each divided task is not uniform, the threshold changing unit The image forming apparatus according to claim 1, wherein the second threshold value is changed such that the task operates on the first multi-core CPU in accordance with the contents of the change.
(4) When the task is an image conversion processing task in a scan transmission job for converting and transmitting scanned image data to a designated file format, the threshold changing unit changes the type of the file format to 3. The image forming apparatus according to claim 1, wherein at least one of the first threshold and the second threshold is changed in accordance with a change content set in response.
(5) When the file format is any of PPTX, CXPS, and CPDF, the threshold value changing unit changes the threshold value to operate with the first multi-core CPU according to the content of the change. Image forming apparatus.
(6) The image forming apparatus according to (5), wherein the task transition determination unit designates activation of the task by the first multi-core CPU.
(7) When the file format is any one of JPEG, TIFF and PDF, the threshold value changing unit changes the threshold value to operate with the second multi-core CPU according to the content of the change. Image forming apparatus.
(8) The image forming apparatus according to (7), wherein the task transition determination unit designates activation of the task by a second multi-core CPU.
(9) The threshold value changing means changes at least one of the first threshold value and the second threshold value in accordance with the change content set according to the resolution of the job. The image forming apparatus according to claim 1.
(10) A first multi-core CPU having a plurality of cores, and a plurality of cores are mounted on the same chip as the first multi-core CPU, and the power consumption is relative to that of the first multi-core CPU An image forming apparatus having a second multi-core CPU having a relatively small processing performance and relatively low processing load based on an operating system for monitoring a load due to a task in the first multi-core CPU and the second multi-core CPU Whether to shift the task from the first multi-core CPU to the second multi-core CPU based on the monitoring step, the load monitored by the load monitoring step, and the first threshold set in advance, or the load The task is selected based on the load monitored by the monitoring step and a preset second threshold value. A task migration determination step of determining whether to migrate from a multicore CPU to a first multi-core CPU, and when it is determined in the task migration determination step that a task is to be migrated, the first one based on the operating system A task transition control step for performing control to shift a task between a multi-core CPU and a second multi-core CPU, and the first threshold value for a task activated by the first multi-core CPU or the second multi-core CPU And / or a threshold changing step of changing at least one of the second threshold values in accordance with a preset change content based on the processing time of the task and the power consumption, and in the task transition determination step, the threshold value If the first threshold or the second threshold is changed by the changing step, Task control method in an image forming apparatus characterized by determining whether to migrate tasks based on the serial load monitoring first threshold after the change and the load monitored by the step or the second threshold value.
(11) A first multi-core CPU having a plurality of cores and a plurality of cores are mounted on the same chip as the first multi-core CPU, and the power consumption is relatively higher than that of the first multi-core CPU Monitor the load due to the task in the first multicore CPU and the second multicore CPU based on the operating system on the CPU of the image forming apparatus provided with the second multicore CPU having a relatively small processing performance and relatively small Whether to shift the task from the first multi-core CPU to the second multi-core CPU based on the load monitoring step, the load monitored by the load monitoring step, and the first threshold set in advance, or The task is selected based on the load monitored by the load monitoring step and a second preset threshold value. A task migration determination step of determining whether to migrate from the second multi-core CPU to the first multi-core CPU; and when it is determined in the task migration determination step that the task is to be migrated, the first based on the operating system A task transition control step of performing control to shift a task between the first multi-core CPU and the second multi-core CPU, and the first for the task activated by the first multi-core CPU or the second multi-core CPU Changing at least one of the second threshold and the second threshold in accordance with a preset change content based on the processing time of the task and the power consumption, and performing the task transition determination step, The first threshold or the second threshold is changed by the threshold changing step. If the load first threshold after the change and the load monitored by the monitoring step or task control program for executing a process for determining whether to migrate tasks based on the second threshold.

  According to the invention described in the preceding paragraph (1), at least one of the first threshold and the second threshold with respect to the task activated by the first multi-core CPU or the second multi-core CPU is the task Based on the processing time and the power consumption, the change is made in accordance with a preset change, and it is determined whether the task is to be transferred based on the changed threshold and the load, and the transfer is performed.

  Therefore, when the task is assigned to the first multi-core CPU but does not require high-load processing, or because the task is assigned to the second multi-core CPU but requires high-load processing When it is necessary to shift the task to the first multi-core CPU early, changing the threshold according to the change content allows the task to be shifted to the multi-core CPU that should be operated early, or the shift can be suppressed. However, the characteristics of the multi-core CPU can be fully exhibited.

  According to the invention described in the preceding paragraph (2), the core of the designated multi-core CPU is designated by designating which of the first multi-core CPU and the second multi-core CPU is to be activated according to the load by the task. The task is started with certainty.

  According to the invention described in the preceding paragraph (3), the task is a task that is divided and executed by a plurality of cores of the second multi-core CPU, and the load of each core by each divided task is not uniform Since there is a difference in processing time for each task, changing the second threshold makes it easy to shift to the first multi CPU, and causes the first multi CPU to execute the task. Thereby, the difference in processing time of each task can be eliminated, and the processing time can be shortened.

  According to the invention described in the preceding paragraph (4), when the task is an image conversion processing task in a scan transmission job for converting the scanned image data into a specified file format and transmitting it, the processing time or consumption At least one of the first threshold and the second threshold is changed according to the change set according to the type of file format that affects the power.

  According to the invention described in the preceding paragraph (5), when the file format is any one of PPTX, CXPS and CPDF, conversion processing to these file formats is high load and processing takes time, so processing performance The threshold value is changed to operate with the first multi-core CPU superior to the above.

  According to the invention described in the preceding paragraph (6), the image conversion processing task whose file format is any of PPTX, CXPS, and CPDF is specified by specifying start-up in the first multi-core CPU. It is reliably activated in the core of the first multi-core CPU.

  According to the invention described in the preceding paragraph (7), when the file format is any one of JPEG, TIFF and PDF, conversion processing to these file formats is relatively light load and processing takes less time. The threshold is changed to operate with the second multi-core CPU with low power consumption.

  According to the invention described in the preceding paragraph (8), the image conversion processing task whose file format is any one of JPEG, TIFF and PDF is designated by designating activation in the second multi-core CPU. It is surely started by the core of the second multi-core CPU.

  According to the invention described in the preceding paragraph (9), since the set resolution of the job affects the magnitude of the load, the changed contents of the threshold are set according to the set resolution of the job, and the first threshold or At least one of the second thresholds is changed.

  According to the invention described in the previous section (10), the task is assigned to the first multi-core CPU, but high-load processing is not necessary, or the task is assigned to the second multi-core CPU but is high When it is necessary to shift the task to the first multi-core CPU early due to the need for heavy processing, change the threshold according to the change content to shift the task to the multi-core CPU to be operated early Because the transition can be suppressed, the characteristics of the multi-core CPU can be fully exhibited to the task.

  According to the invention described in the previous section (11), the task is assigned to the first multi-core CPU but high-load processing is not necessary, or the task is assigned to the second multi-core CPU but is high When it is necessary to shift the task to the first multi-core CPU early due to the need for heavy processing, change the threshold according to the change content to shift the task to the multi-core CPU to be operated early Since the transition can be suppressed, it is possible to cause the CPU of the image forming apparatus to execute processing capable of sufficiently exhibiting the characteristics of the multi-core CPU with respect to the task.

FIG. 1 is a block diagram showing the configuration of an image forming apparatus according to an embodiment of the present invention. (A)-(C) are the figures for demonstrating the structure and basic operation | movement of CPU. It is a figure for demonstrating the relationship of the load and threshold value by the task at the time of normal times. It is an explanatory view about change of a threshold. It is a table | surface which shows the change content of the threshold value set based on processing time and power consumption about an image conversion process task. It is a functional block diagram of CPU. It is a flowchart which shows a task transfer determination process. It is a flowchart which shows the content of the 1st task determination processing of FIG.7 S02. It is a flowchart which shows the content of the 2nd task determination processing of FIG.7 S03.

  Hereinafter, an embodiment of the present invention will be described based on the drawings.

  FIG. 1 is a block diagram showing the configuration of an image forming apparatus 1 according to an embodiment of the present invention. In this embodiment, as the image forming apparatus 1, an MFP, which is the multi-function digital multifunction peripheral described above, 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 and an image processing ASIC 20. These are connected to the CPU 11 via a bus.

  The CPU 11 integrally controls the entire image forming apparatus 1 and controls to use basic functions such as a copy function, a printer function, a scan function, and a facsimile function. The CPU 11 is a task transition control unit 111 and a load monitoring unit 112 that are functionally configured by executing an OS (operating system), and a task that is functionally configured by executing an application (MFP application) A transition determination unit 113, a task activation core determination unit 114, and a threshold change unit 115 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 the 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 composed of, for example, a non-volatile storage device such as a hard disk drive (HDD), and stores the OS, the MFP application, the image data of the document scanned by the scanner unit 14, etc. In the form, a table is stored in which change contents for changing the first threshold and the second threshold described later based on the task processing time and the power consumption are defined in advance.

  The printer unit 16 prints the image data of the document scanned by the scanner unit 14 and the print data from the outside according to the instructed mode.

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

  The network I / F 18 transmits and receives data by controlling communication with another image forming apparatus on the network and another external device such as a user terminal.

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

  As shown in FIG. 2A, the CPU 11 is a single semiconductor in which 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 are referred to as SoC. It is mounted on a chip. The first multi-core CPU 115 is a CPU with high power consumption but high processing power, and the second multi-core CPU 116 is a CPU with relatively low power consumption but relatively low processing power than the first CPU 115.

  In addition, the first multi-core CPU 115 includes four cores (also referred to as big cores) 115 a to 115 d, and the second multi-core CPU 116 is paired with each core 115 a to 115 d of the first multi-core CPU 115 4 Each core (also referred to as LITTLE core) 116a to 116d is provided. In this embodiment, a multiprocessing model in which all cores of each multicore CPU 115 and 116 are ON is applied, and in particular, the scheduler of the OS according to the load all cores of the first multicore CPU 115 and the second multicore CPU 116 The above-mentioned GTS, which distributes tasks for the above, is applied.

  In the multiprocessing model, there are eight cores visible to the OS as shown in FIG. FIG. 2A shows a state in which each task is assigned to the cores 116a to 116d of the second multicore CPU 116 having low processing performance but low power consumption, for example, the second multicore When the load on the core 116a of the CPU 116 reaches a preset threshold, some or all of the tasks operating on the core 116a are transferred to the core 115a or the like of the first multicore CPU 115 based on the OS ing.

  In FIG. 2A, 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 an interrupt processing task (denoted "interrupt"), and the core 116c is to scan an image. A scan control task (denoted as "scan") for controlling a scan job for transmitting image data obtained by the above to a predetermined destination is assigned.

  Moreover, even if it is the same task, the task structure which starts with several cores and implements a process while synchronizing at fixed intervals may be employ | adopted. In this embodiment, for the RIP processing task for expanding data described in PostScript, which is a page description language, into bitmap data that can be printed or displayed, tasks are assigned across the core 116 a and the core 116 b. . Specifically, a task called a first RIP processing task (RIP processing task 1) is generated in the core 116a and a task called a second RIP processing task (RIP processing task 2) is generated in the core 116b. The first half is processed separately by the RIP processing task 1 of the core 116a, and the second half is separately processed by the RIP processing task 2 of the core 116b, and the RIP processing 1 by the RIP processing task 1 and the RIP processing 2 by the RIP processing task 2 are completed. When the upper module determines that any processing is completed, the data combining the processing results is transferred to the next processing, and the RIP processing of the next band data is performed.

  Furthermore, in this embodiment, tasks are assigned to the image conversion processing task for converting scanned image data into a file format such as PDF or JPEG specified by a user or the like, 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 other half of the image conversion processing task 2 of the core 116d separately perform the image conversion processing task 1 and the image conversion processing task 2 by the image conversion processing task 1, respectively. Synchronize the completion of the image conversion process 2 by the above, and if the upper module determines that any process is completed, store the image data combining the respective process results in the storage unit 15 etc. which is a data storage area, and the next image Perform image conversion processing of data.

  In FIG. 2A, when the scanning operation is started, as shown in FIG. 2B, a scan control task and an image conversion processing task are activated. Print control task and RIP process task are not working. In FIG. 2, the operating task is hatched.

  For example, transmission of data converted to a predetermined file format (scan transmission) is started, and when the core load by the task reaches a preset threshold, part or all of the task is transferred to the first multi-core CPU 115 . In this embodiment, as shown in FIG. 2C, the image conversion processing task is shifted to the cores 115c and 115d of the first multi-core CPU 115.

  At this time, when the OS determines that the load of the image conversion processing is high, it is specified that the next image conversion processing task is started by the cores 115 c and 115 d of the first multi-core CPU 115.

  Here, task transition control by the OS is basically easy to shift from the second multi-core CPU 116 to the first multi-core CPU 115 side. Specifically, as shown in FIG. 3A, when the processing load (Load ave.) In the second multi-core CPU 116 increases and reaches the second threshold L2, it shifts to the first multi-core CPU 115 However, the second threshold L2 is set to a relatively small value. On the other hand, in the first multi-core CPU 115, when the processing load (Load ave.) Decreases and reaches the first threshold L1, the first multi-core CPU 116 is shifted to the second multi-core CPU 116, but is not shifted easily. Is set to a smaller value. Such a configuration is converted to a file format such as PPTX (a file created by Microsoft Office PowerPoin), compact XPS (referred to as XPS), XPS: XML Paper Specification (CXPS), CPDF, etc., and processing for setting resolution of 400 dpi or more While it is effective when carrying out high-load processing such as, etc., when carrying out relatively light-load processing such as conversion processing to file formats such as JPEG, TIFF and PDF In order to perform processing in the first multi-core CPU 115, performance (processing time) is prioritized over power consumption.

  Therefore, in this embodiment, at least one of the first threshold L1 and the first threshold L2 described above is changed with respect to the image conversion processing task according to the change contents set in advance based on the processing time and the power consumption. It has become.

  As a basic idea, for example, when the conversion processing to a file format such as JPEG, TIFF, and PDF is activated by the second multicore CPU 116 in the scan transmission job, the second threshold is increased to make the first multicore By suppressing task migration to the CPU 115, power consumption is reduced.

  When the boot core is on the first multicore CPU 115 side, the core of the second multicore CPU 116 is designated as the boot core.

  However, if the corresponding task has already been started by the multi-core CPU 116 and the processing is performed by multiple cores, and the processing load on the multiple cores is not uniform, transfer to the multi-core CPU 115 even for light load processing The second threshold L 2 is reduced by one step for easy processing, and the processing time is shortened by causing the multi-core CPU 115 to process.

  In addition, when the conversion process to a file format such as JPEG, TIFF, and PDF is operating on the first multi-core CPU 115, as shown in FIG. 4, the first threshold L1 is increased to make the second multi-core CPU 115 Reduce power consumption by promoting the transition to

  On the other hand, when the start core of the image conversion process to a file format such as PPTX, CXPS, and CPDF is on the side of the second multicore CPU 116 in the scan transmission job, the core of the first multicore CPU 115 is designated as the start core. When the second multi-core CPU 116 is already activated, the second threshold L2 is reduced to promote task migration to the first multi-core CPU 115, thereby shortening the processing time.

  A table showing changes in the threshold is shown in FIG. In this example, the processing time and power consumption depend on the load by the image conversion processing task, and the load depends on the file format and setting resolution of the image conversion processing task, so changing the threshold based on the file format and setting resolution The content is defined. The setting resolution is exemplified by 200 dpi, 300 dpi, 400 dpi, and 600 dpi, but is not limited thereto.

  In FIG. 5, when the file format is CXPS or PPTX, the first multi-core CPU 115 (big side) is activated regardless of the set resolution, and the first multi-core CPU 115 facilitates processing. The threshold L1 is set to be changed. When the file format is CPDF, the first multi-core CPU 115 is activated only when the setting resolution is 400 dpi or higher, and when the file format is XPS, the first multi-core CPU 115 side only when the setting resolution is 600 dpi or higher. In order to facilitate the processing by the CPU 115, the first threshold L1 is set to be changed.

  If the file format is CPDF and the setting resolution is 300 dpi, or if the file format is XPS and the setting resolution is 400 dpi and 300 dpi, the first multi-core CPU 115 can easily process the multi-core CPU on the activated side. The threshold is changed. If the file format is CPDF or XPS and the setting resolution is 200 dpi, or if the file format is PDF and the setting resolution is 600 dpi, there is no change in the threshold.

  When the file format is PDF and the setting resolution is 400 dpi and 300 dpi, or when the file format is TIFF and JPEG and the setting resolution is 600 dpi, the second multicore CPU 116 (LITTLE side) is activated to facilitate processing. The threshold on the other multi-core CPU is changed.

  When the file format is PDF and the setting resolution is 200 dpi, and when the file format is TIFF and JPEG and the setting resolution is 400 dpi or less, the second multi-core CPU 116 is activated and the second multi-core CPU 116 easily processes In other words, the second threshold L2 is changed so as not to shift to the first multi-core CPU 115.

  Although not shown, the amount of change of each threshold is also preset.

  As described above, in this embodiment, the change content of the threshold for the image conversion processing task is set according to the file format and the resolution related to the processing time and the power consumption, but the change content is defined based only on the file format. It may be done. For example, when the file format is PPTX, CXPS, or CPDF, the threshold value of the activated multi-core CPU is changed so that processing is easily performed by the first multi-core CPU 115, and the file format is PDF, TIFF In the case of JPEG and JPEG, the threshold on the activated multi-core CPU is changed so that processing can be easily performed by the second multi-core CPU 115, and in the case where the file format is XPS, the threshold is not changed. good.

  However, by adding the setting resolution to the determination factor in addition to the type of file format, finer control becomes possible. Also, the change contents of the threshold may be set according to only the set resolution, not the type of file format.

  The changed contents of the set threshold are stored in the storage unit 15 or the like, and in the task transition determination control, the changed contents according to the task are called, and the threshold is changed according to the changed contents.

  Thus, in this embodiment, the task is assigned to the first multi-core CPU 115 but high-load processing is not required, or the task is assigned to the second multi-core CPU 116 but high-load processing When it is necessary to shift the task to the first multi-core CPU 115 early because of the need to change the threshold according to the contents of the change, it is possible to shift the task to the multi-core CPU that should be operated early. Since it can be suppressed, it is possible to make the task fully exhibit the characteristics of the multi-core CPU.

  A functional block diagram of the CPU 11 is shown in FIG. As described above, the CPU 11 executes the OS to execute the task transition control unit 111 and the load monitoring unit 112, and the task transition determination unit 113 configured to execute the MFP application. The task activation core determination unit 114 and the threshold change unit 115 are provided.

  The task migration control unit 111 performs migration control when the task migration determination unit 113 determines that the task is to be migrated to the core of the other multi-core CPU.

  The load monitoring unit 112 monitors the load due to the task of each core in the first multicore CPU 115 and the second multicore CPU 116.

  The task transition determination unit 114 determines the task of the core whose load has reached the threshold based on the load of the core monitored by the load monitoring unit 112 and the first threshold L1 and the second threshold L2 set in advance. Determine whether to move to the core of the other multi-core CPU. In addition, for example, when the file format of the image conversion processing in scan transmission job is CXPS or PPTX, when the load by the task of the input job is large, the first multi-core CPU 115 is instructed to start the task. If the load by the task of the input job is small, as in the case where the set resolution is 400 dpi or less in TIFF and JPEG, the second multi-core CPU 116 is specified to start the task.

  The task activation core determination unit 114 determines a core that activates a task, and based on this determination, the task is activated in the core.

  The threshold changing unit 115 changes one or both of the first threshold L1 of the first multi-core CPU 116 and the second threshold L2 of the second multi-core CPU 116 as necessary.

  FIG. 7 is a flowchart showing an example of the task transition determination process. This process is executed by the CPU 11 operating according to the OS and the MFP application.

  In this embodiment, the task is an image conversion processing task of a scan transmission job, and this task is supposed to be activated by the core of the second multi-core CPU 116.

  In step S01, the load by the task of each core of the second multi-core CPU 116 is monitored, and in step S02, the first task determination process is executed. If it is determined to shift, after shifting the task, the process returns to step S01. If it is determined not to shift, the second shift determination process is performed in step S03, and then the process returns to step S01.

  FIG. 8 is a flowchart showing the contents of the first task transition determination process of step S02 of FIG.

  In step S 021, it is immediately determined whether it is a load that requires migration to the first multi-core CPU 115, in other words, whether it is a task with the file format and setting resolution indicated by ◎ in the table of FIG. If the load does not require migration to the multi-core CPU 115, the process proceeds to step S03. If the load requires migration to the first multi-core CPU 115 immediately, the first task migration control unit 111 is selected in step S022. After instructing task migration (task activation) to the multi-core CPU 115, the process returns to step S01. In accordance with this instruction, the task transfer control unit 111 transfers the task to the first multi-core CPU 115.

  FIG. 9 is a flowchart showing the contents of the second task transition determination process of step S03 of FIG.

  In step S031, it is determined whether the task is a core that operates by being divided by multiple cores, and if it is not a core that is operated by dividing by multiple cores (NO in step S031), the process returns to step S01. If it is a core which is divided and operated by a plurality of cores (YES in step S031), the process proceeds to step S032.

  In step S032, it is determined whether the load is uniform in each core. If uniform (YES in step S032), the process returns to step S01. If not uniform (NO in step S032), the process proceeds to step S033.

  In step S033, it is determined whether the set job is a scan transmission job, and if it is not a scan transmission job (NO in step S033), the process returns to step S01. If it is a scan transmission job (YES in step S033), the process advances to step S034.

  In step S034, it is determined which of the tables in FIG. 5 the image conversion task corresponds to from the relationship between the file format and the set resolution.

  If the task corresponds to “〇”, the second threshold is changed in step S035 so that the task can easily shift to the first multi-core CPU 115, and then in step S037, the next activation as necessary The task is set to the first multicore CPU 115 side, and the process returns to step S01.

  If the task corresponds to "-" in step S034, the process returns to step S01 without changing the threshold value.

  If the task corresponds to “Δ” or “·” in step S034, the second threshold is changed in step S037 so that the task can easily operate on the second multicore CPU 116 side, and then in step S038 Then, if necessary, the next boot task is set to the second multicore CPU 116, and the process returns to step S01.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment.

  For example, although the case where the task is the image conversion processing task in the scan transmission job has been described, the task is not limited to this, and the RIP processing and the image conversion processing task in the image forming apparatus without the hard disk are the second The first threshold and / or the second threshold are changed to make it easy to operate on the multi-core CPU 116 to prioritize power consumption, and in the case of sharing the RIP / image conversion memory, to make the first multi-core CPU 115 easy to operate The threshold of 1 and / or the second threshold may be changed to prioritize the processing time.

  Further, the determinations in step S031 and step 032 in FIG. 9 may not necessarily be performed, and if the load is not uniform in each core in step S032 (NO in step S032), the task is immediately transferred to the first multi-core CPU 115 It may be configured to

1 Image forming apparatus 11 CPU
12 ROM
13 RAM
14 scanner unit 15 storage unit 17 operation unit 111 task transition control unit 112 load monitoring unit 113 task transition determination unit 115 threshold change unit

Claims (11)

A first multi-core CPU having a plurality of cores,
A second multicore CPU mounted on the same chip as the first multicore CPU and having a plurality of cores, which consumes relatively less power and has relatively lower processing performance than the first multicore CPU When,
Load monitoring means for monitoring the load caused by tasks in the first multi-core CPU and the second multi-core CPU based on an operating system;
Based on the load monitored by the load monitoring means and the first threshold set in advance, it is monitored whether the task is to be transferred from the first multi-core CPU to the second multi-core CPU or by the load monitoring means A task transition determination unit that determines whether to shift the task from the second multi-core CPU to the first multi-core CPU based on the load to be performed and a preset second threshold value;
A task transition control unit that performs control of causing a task to be shifted between the first multi-core CPU and the second multi-core CPU based on the operating system when it is determined that the task is to be shifted by the task shift determination unit When,
At least one of the first threshold and the second threshold is set in advance based on the processing time of the task and the power consumption with respect to the task activated by the first multicore CPU or the second multicore CPU. Threshold changing means for changing according to the contents of the change,
Equipped with
When the first threshold or the second threshold is changed by the threshold changing means, the task transition judging means changes the load monitored by the load monitoring means and the first threshold or second after the change. An image forming apparatus characterized by determining whether or not to shift a task based on a threshold.   The image forming apparatus according to claim 1, wherein the task transition determination unit specifies which of the first multi-core CPU and the second multi-core CPU is to be activated according to a load of a task.   When the task is a task that is divided and executed by a plurality of cores of the second multi-core CPU, and the load of each core by each divided task is not uniform, the threshold changing unit changes The image forming apparatus according to claim 1, wherein the second threshold is changed such that the task operates on the first multi-core CPU according to the content.   When the task is an image conversion processing task in a scan transmission job that converts and transmits scanned image data to a specified file format, the threshold changing unit sets the threshold according to the type of the file format. The image forming apparatus according to claim 1, wherein at least one of the first threshold and the second threshold is changed in accordance with the contents of the change.   5. The image forming method according to claim 4, wherein when the file format is any of PPTX, CXPS, and CPDF, the threshold changing unit changes the threshold so as to operate on the first multi-core CPU according to the contents of the change. apparatus.   The image forming apparatus according to claim 5, wherein the task transition determination unit specifies activation of the first multi-core CPU for the task.   5. The image forming method according to claim 4, wherein when the file format is any one of JPEG, TIFF, and PDF, the threshold changing unit changes the threshold to operate with the second multi-core CPU according to the contents of the change. apparatus.   The image forming apparatus according to claim 7, wherein the task transition determination unit designates activation of the task by a second multi-core CPU.   9. The apparatus according to claim 1, wherein the threshold changing unit changes at least one of the first threshold and the second threshold in accordance with a change set according to a resolution of a job. Image forming device. A first multi-core CPU having a plurality of cores,
A second multicore CPU mounted on the same chip as the first multicore CPU and having a plurality of cores, which consumes relatively less power and has relatively lower processing performance than the first multicore CPU When,
An image forming apparatus provided with
A load monitoring step of monitoring a load due to a task in the first multi-core CPU and the second multi-core CPU based on an operating system;
Based on the load monitored by the load monitoring step and the first threshold set in advance, it is monitored whether the task is to be transferred from the first multi-core CPU to the second multi-core CPU or by the load monitoring step A task migration determination step of determining whether to migrate the task from the second multi-core CPU to the first multi-core CPU based on the load to be performed and a preset second threshold value;
A task transfer control step of performing control to transfer a task between the first multi-core CPU and the second multi-core CPU based on the operating system when it is determined in the task transfer determination step that the task is to be transferred When,
At least one of the first threshold and the second threshold is set in advance based on the processing time of the task and the power consumption with respect to the task activated by the first multicore CPU or the second multicore CPU. A threshold change step of changing according to the changed contents;
To carry out
In the task transition determination step, when the first threshold or the second threshold is changed by the threshold change step, the load monitored by the load monitoring step and the first threshold after the change or the second threshold A task control method in an image forming apparatus, which determines whether or not to shift a task based on a threshold. A first multi-core CPU having a plurality of cores,
A second multicore CPU mounted on the same chip as the first multicore CPU and having a plurality of cores, which consumes relatively less power and has relatively lower processing performance than the first multicore CPU When,
To the CPU of the image forming apparatus provided with
A load monitoring step of monitoring a load due to a task in the first multi-core CPU and the second multi-core CPU based on an operating system;
Based on the load monitored by the load monitoring step and the first threshold set in advance, it is monitored whether the task is to be transferred from the first multi-core CPU to the second multi-core CPU or by the load monitoring step A task migration determination step of determining whether to migrate the task from the second multi-core CPU to the first multi-core CPU based on the load to be performed and a preset second threshold value;
A task transfer control step of performing control to transfer a task between the first multi-core CPU and the second multi-core CPU based on the operating system when it is determined in the task transfer determination step that the task is to be transferred When,
At least one of the first threshold and the second threshold is set in advance based on the processing time of the task and the power consumption with respect to the task activated by the first multicore CPU or the second multicore CPU. A threshold change step of changing according to the changed contents;
To run
In the task transition determination step, when the first threshold or the second threshold is changed by the threshold change step, the load monitored by the load monitoring step and the first threshold after the change or the second threshold A task control program for executing a process of determining whether to shift a task based on a threshold value.