JPS61233838A - Information processor - Google Patents

Abstract

PURPOSE:To eliminate the overhead of task change by inserting a special machine language instruction to a part of a machine language instruction program where task change is possible with a comparatively small overhead. CONSTITUTION:The machine language instruction representing a task change chance designation instruction is inserted to a part in the program where the overhead for task change is less. When the machine language instruction fed to a decode circuit 1 read in this way is the task change chance designation instruction, it is decoded and a coincidence signal is fed to a task change start circuit 3. The task change start circuit 3 checks whether or not a task change request is stored in a task change request holding circuit 2 in response to the supply of the coincidence signal and when the request is held, a task change start signal is generated to start the task change processing. On the other hand, when not held, no task change start signal is raised and the program execution is transferred to an instruction next to the task change chance designation instruction.

Description

[Detailed description of the invention] Large comviators with particularly complex internal conditions.

Super Combi Island - Concerning task switching in a vector processor.

(Conventional technology and its problems) Multitasking methods, in which a single information processing device executes multiple tasks, have been commonly used in the past, and it is known that this technique can improve the efficiency of using the information processing device. It is being (@"Electronic Computer (1)' by Hiroshi Kaneda, Corona Publishing, pp. 147-151, 1971).

When switching the task to be actually executed on the processor, the state information regarding the currently executing task is saved to the task control block (hereinafter referred to as rollout), and the state information of the task to be executed next is saved. is read from the corresponding task control block and written back to the processor (hereinafter referred to as roll-in). Conventionally, this task switching was performed between one machine language instruction and another machine language instruction.

However, as processors in information processing devices become larger, pipeline processing is required to increase speed. In processors that incorporate advanced control, such as the above, there is a problem in that switching tasks interrupts the pipeline during execution, resulting in a significant drop in processing efficiency.

Furthermore, a vector processor that performs vc1 vector processing at high speed has a large number of registers dedicated to vector processing (usually called vector registers) as internal registers, and when these are used, their contents are However, it is necessary to roll out and roll in the internal state, and there is a problem in that the overhead of task switching becomes extremely large.

(Object of the Invention) The object of the present invention is to execute one machine language instruction program in order to reduce the overhead of the conventional task switching described above;
In this case, a special machine language instruction is embedded in a part of the i1* program where the internal state is small and task switching can be performed with relatively small overhead even if a task switching occurs, and the detection of this instruction is detected. It is an object of the present invention to provide an information processing device that can take advantage of this opportunity to perform necessary task switching and reduce task switching overhead.

(Structure of the Invention) The apparatus of the present invention [1 is provided with a specific machine language instruction indicating that the overhead of task switching is small, and an instruction decoding means for decoding the specific machine language instruction and generating a first signal;
storage means for temporarily storing a task switching request; and a task for checking the storage means in response to the supply of the first signal and generating an activation signal for starting task switching processing when the task switching request is stored. and switching activation means.

(Example) Next, the sacrifice f+1 of the present invention will be explained with reference to the drawings.

Figure iE1 is a block diagram showing the main parts of the side of the present invention, including a decoding circuit 1 for decoding a specific command, a task switching request holding circuit 2 for temporarily storing a task switching request, and a task for starting task switching. It includes a switching starting circuit 3.

As the format of the above specific instruction (hereinafter referred to as the task switching trigger specification instruction) is shown in Figure 3, it is a machine language instruction consisting of only a 1-byte instruction code section, and this is the instruction code for the task switching trigger specification instruction. It has a specific value indicating that it is a switching trigger designation command. However, this instruction is assumed to be used to indicate a point in the program where the overhead of task switching is low. Therefore, the location in the program where this instruction is located indicates the location that triggers task switching.

It is assumed that the task switching request inputted to the task switching request holding circuit 2 is compared with the task currently being executed, and a switching request for a task that requires switching with the highest priority arrives.

@2 Figure is a flowchart showing the operation of this embodiment.

The operation of this embodiment will be explained with reference to FIGS. 1 and 2.

A machine language instruction to be executed is read out and supplied to the decoding circuit 1. When the supplied machine language command is a task switching trigger designation command, the decoding circuit 1 decodes it and supplies a matching signal to the task switching starting circuit 3. In response to the supply of the matching signal to the task switching starting circuit 3, it is checked whether the task switching request is held in the task switching request holding circuit 2. If the task switching request is being held, the task switching starting circuit 3 starts the task switching. A signal is generated to start the task switching process. Task switching request holding circuit 2 When the task switching request is not held, the task switching start signal is not issued and the program execution moves to the next command after the task switching trigger designation command.

The embodiments of the present invention have been described above, but as is clear from the explanation of the five embodiments, the gist of the present invention is to provide a special machine language instruction that shows that the overhead of task switching is small, and to use this instruction. When executing this command, if there is a request for task switching, processing related to task switching will be started using this command as a trigger, and if there is no request, the task switching will be performed so that the function equivalent to an invalid command is performed. Is it possible to improve the processing capacity of information processing equipment by ensuring that task switching occurs only when there is little overhead? It's about making it possible.

Therefore, it is clear that there are several ways to implement the invention as long as they do not go against the spirit of the invention.

The reason for this is that it is not directly related to the above-mentioned gist of the present invention, and that it can be realized by a conventionally known method. I'll omit the explanation. That is, the former accepts interrupts such as external interrupts and interval timer interrupts, analyzes their contents, and if there is a task that has become newly executable due to this interrupt, it updates the state of this task and updates this task. It has the function of comparing the task with the currently executing task, determining whether it is necessary to switch the task, and holding this request if necessary (the task switching request holding circuit 2 The latter (which holds the request) is the part that controls actual task switching based on the former's decision.

In this embodiment, these are all dedicated nodes.
It is possible to implement the process even if it is realized in A, or even if some or all of the processing is realized using the existing hardware v′7τγ in the information processing device. In each of these cases, the process is It will be obvious that the specific implementation methods of the present invention are different.

For example, if it is implemented with dedicated hardware, interrupts, etc. are accepted in parallel with the execution of tasks in the processor section, and are performed for task management, and the currently executing task and new tasks are made executable. determine whether it is necessary to switch between the two and maintain this request if necessary.

When execution of a task switching trigger designation command is detected in the execution of a task, the previously held request is checked, and if there is one, the task switching means is activated. A task currently being executed is rolled out to a task switching means running on dedicated hardware, a new task is rolled in, and processing in the processor section is resumed. This starts a new task. When the rolled-out task is next rolled in, execution will resume from the command following the task switching trigger designation command.

Furthermore, it is also possible to treat only interrupt requests and the like as requests related to task switching, and to determine whether or not task status changes and task switching are necessary at the time when a special instruction according to the present invention is executed. Dew.

(Effects of the Invention) By embedding the task switching trigger designation instruction according to the present invention in a program running on a vector processor, for example, in a place where the previously used vector register has been released, it is possible to eliminate the need to save the vector register. This makes it possible to perform task switching at high speed, and has the effect of improving the processing capacity of the TW information processing device.

[Brief Description of the Drawings] Figure 1 is a block diagram showing the main parts of an embodiment of the present invention, Figure 2 is a flowchart showing the operation of Figure 1, and Figure 3 is a flow diagram of the instructions used in the present invention. It is a format diagram. 1... Decoding circuit, 2... Task switching request holding circuit, 3... Task switching starting circuit.

Claims (1)

[Scope of Claims] A specific machine language instruction indicating that the overhead of task switching is small is provided, an instruction decoding means for decoding the specific machine language instruction and generating a first signal, and a memory for temporarily storing the task switching request. and task switching starting means for detecting the storage means in response to the supply of the first signal and generating a starting signal for starting task switching processing when a task switching request is stored. Information processing equipment.