JPH0518139B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a scheduler used in an electronic computer, and particularly to a scheduler having a real-time processing function that gives priority to a specific process.

[Technical background of the invention and its problems]

Traditionally, the scheduler in electronic computers was the fourth
It was configured as shown in the figure, and operated using a so-called time-sharing scheduling method in which CPU time was allocated equally to each user process. In addition, in the figure,
KP is kernel process, UP is user process,
SCM is a scheduling mechanism, and TPRQ is a time-sharing queue.

Therefore, conventionally, when control is transferred from one process to another, it must be done only after the CPU time has been consumed by the other process for a certain period of time. For this reason, in the past, there was a problem that it was not possible to deal with a situation where a certain task was urgently processed.

[Purpose of the invention]

The present invention has been developed in view of the above-mentioned circumstances, and it is possible to give priority to a specific process for a certain period of time to give the right to use the processing equipment, thereby increasing the efficiency of a system that handles highly urgent process operations. The purpose of this invention is to provide a scheduler that can perform good process control.

[Summary of the invention]

The present invention provides not only time-sharing scheduling in a scheduler for an electronic calculator.
A process that has a real-time processing mechanism that gives top priority to execution when an execution request is received from a certain process, and thereby requests processing within a certain period of time. The right to use the processing equipment can be granted with the highest priority for a certain period of time, and efficient process control can be performed in a system that handles highly urgent process operations.

[Embodiments of the invention]

FIG. 1 is a block diagram showing an embodiment of the apparatus according to the present invention. In the figure, 1 is a kernel process (KP), which processes various requests from user processes (UP). 2 is a user process, which can be roughly divided into a time-sharing process and a real-time process. 3 is a real-time process registration processor (RTPR), and 4 is a time-sharing process registration processor (TDPR). 5 is a real-time process registration queue (RPRQ), and 6 is a time-sharing process registration queue (TPRQ). 7 is a real-time process generator (RTPG), which converts the process registered in the real-time process registration queue 5 into a real-time process. 8
is the user process state identifier (UPSI),
The status of each process is taken over by a process priority processing mechanism (PPD) 9. 10 is a process selection mechanism (PSM) that selects the process with the highest priority. 11 is kernel process 1
Dispatch mechanism (KPD) when selecting 1
2 is a dispatch mechanism (RPD) when a real-time process is selected from among the user processes 2, and 13 and 14 are dispatch mechanisms (TPD) when a simultaneous split process is selected.
15 indicates the selected kernel process, and 16 indicates the same user process. 17 is a scheduling mechanism (SCM) including a real-time processing mechanism.

Here, the operation of the configuration shown in FIG. 1 will be explained. When the kernel process 1 goes to sleep, control immediately passes to the process priority processing mechanism 9, which creates the process with the highest priority. Real-time processes are set to the highest priority. The process with the highest priority is selected by the process selection mechanism 10. If kernel process 1 is selected, control is transferred to kernel dispatch mechanism 11,
Kernel process 1 gains the right to use the CPU again.
When the user process 2 issues a real-time process system call, the real-time process register 3 sends a real-time process registration queue 5.
will be registered. This cue is schedule mechanism 1
Referenced in 7. The user process comes to have the attributes of a real-time process by the real-time process generator 7. A real-time process created by this real-time process creator 7 is distinguished from a time-sharing process by a user process state identifier 8. The differentiated real-time processes are selected by the process selection mechanism 10 in preference to time-sharing processes. If there are multiple real-time processes, the appropriate one is selected based on CPU usage, memory usage, priority value, etc. The selected real-time process is dispatched by the real-time process dispatch mechanism 12 by giving it exclusive CPU time and time to allow dispatch to other processes. After using the CPU for a given amount of time, dispatch to other processes is allowed.

Here, the operation of the main parts in FIG. 1 will be explained in more detail with reference to FIGS. 2 and 3.

1 Real-time process queue registration In the real-time process processor 3, as shown in FIG. 2, a real-time process registration queue 5 is created separately from the time-sharing process registration queue 6. A new real-time process (RTP _(N) ) is registered at the forefront. Scanning starts from the real-time queue pointer (RQP), so it can be quickly registered at the forefront.

2 Real-time process creator The real-time process creator 7 creates a process table (P-TBL) as shown in Figure 3.
a real-time indicator (A) at a specific location of
Set the amount of CPU exclusive time (B) and the amount of CPU usage allowed for other processes (C).

3 Process Selection Mechanism The process selection mechanism 10 first scans the real-time process registration queue 5 and then scans the time-sharing process registration queue 6. If there are any processes registered in the real-time process registration queue 5, the one with the highest priority is selected. In this case, the time-sharing process registration queue 6 is not scanned; if there is nothing registered in the real-time process registration queue 5, or if a real-time process is waiting for an event, the time-sharing process registration queue 6 is scanned. is scanned.

4 Real-time process dispatch mechanism Real-time process dispatch mechanism 12
Now, for the selected real-time process,
The amount of CPU exclusive time registered in the process table (P-TBL) in FIG. 3 is continuously dispatched to the corresponding process. If this process is executable, even if interrupts or traps occur from other sources, control is immediately transferred to the relevant real-time process again after processing them.
No other processes can be executed. When the corresponding process consumes the amount of CPU exclusive time registered in the process table (P-TBL), other processes will use the amount of CPU usage allowed for other processes registered in the process table (P-TBL). gives CPU usage rights to When another process consumes this CPU usage, process scheduling starts again from the process priority processing mechanism 9.

By providing such a real-time scheduling mechanism, it is possible to specify the CPU exclusive time for a process, so that tasks for a certain process can be processed preferentially. Also, the state can be changed from a real-time process to a time-sharing process, or from a time-sharing process to a real-time process.
Additionally, it can support measurement equipment that requires real-time performance.

Above, we have discussed that the CPU exclusive time of a process is variable, and that real-time processes are given CPU usage rights preferentially over time-sharing processes. By designing a system that combines functions, shared memory functions, semaphore, etc., it is possible to construct a more complete real-time subsystem system.

〔Effect of the invention〕

As detailed above, the scheduler of the present invention not only performs time-sharing scheduling, but also real-time processing that executes a specific process with top priority when an execution request is received from that process. By adopting a structure that includes a mechanism, it is possible to grant the right to use the processing device with the highest priority for a certain period of time to a process that requests processing within a certain period of time. Efficient process control can be performed in a system that handles process operations.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
Fig. 2 is a diagram for explaining the operation of the real-time process registration processor in the above embodiment, Fig. 3 is a diagram showing a process table in the above embodiment, and Fig. 4 is a block diagram showing a conventional scheduler. It is a diagram. 1,15...Kernel process (KP), 2,1
6... User process (UP), 3... Real-time process registration processor (RTPR), 4... Time-sharing process registration processor (TDPR), 5... Real-time process registration queue (RPRQ), 6... Time-sharing Process registration queue (TPRQ), 7...Real-time process creator (RTPG), 8...User process state identifier (UPSI), 9...Process priority processing mechanism (PPD), 10...Process selection mechanism (PSM) ), 11... kernel process dispatch mechanism (KPD), 12... real-time process dispatch mechanism (RPD), 13, 14... time-sharing process dispatch mechanism (TPD), 17...
...Schedule mechanism.

Claims (1)

[Claims] 1. A real-time process registration processing means for registering a specific process as a real-time process from the processes to be executed; a real-time process queue registration means for registering the real-time process registered by the registration processing means; Create the target process as a real-time process by referring to the queue registration means, and respond to the real-time process.
real-time process creation means for registering CPU exclusive time and CPU usage permission time given to other processes in a process table; user process state identification means for distinguishing the real-time process created by the real-time process creation means from a time-sharing process; process selection means for selecting the real-time process identified by the user process state identification means with priority over the time-sharing process;
The CPU exclusive time registered in the process table is allocated to the real-time process selected by the process selection means, and after the CPU exclusive time is consumed, the real time process selected by the process selection means is assigned the CPU exclusive time registered in the process table to other processes. and a dispatch means that grants CPU usage rights for the CPU usage permission time, and is configured to grant CPU usage rights to other processes for a predetermined period of time for each processing of each real-time process selected as a priority. Featured scheduler.