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CFQ (complete fair quenching) dispatching method

A dispatching method and elevator dispatching algorithm technology, applied in the direction of instruments, electrical digital data processing, etc., can solve problems such as I/O performance degradation, and achieve the effect of improving operating efficiency

Inactive Publication Date: 2015-02-18
LANGCHAO ELECTRONIC INFORMATION IND CO LTD
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  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to provide a CFQ scheduling method, which can overcome the difficult problem that the I / O performance of the old CFQ algorithm declines when intensive I / O requests occur

Method used

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Embodiment Construction

[0028] Below with reference to accompanying drawing, content of the present invention is set forth in more detail:

[0029] (1) First, if figure 1 Inter-group scheduling: The I / O requests proposed by the process are grouped according to the type of device being operated, and each group selects the I / O operation corresponding to the device type, that is, different devices have different interrupt vectors. Each group has a corresponding weight. The greater the weight, the smaller the time slice, and the more opportunities for inter-group scheduling. All groups are arranged into a red-black tree according to the time slice. If the special operation flag Intense=1 of a certain group, the I / O request of this group is satisfied first, and the method is to raise its weight to the highest until the operation of the I / O request of this group is allocated.

[0030] (2) Then if figure 2 Intra-group scheduling: For intra-group I / O requests, queues are allocated in two different ways ac...

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Abstract

The invention provides a CFQ (complete fair quenching) dispatching method, and relates to the field of linux kernel I / O (input / output) dispatching. The CFQ dispatching method comprises the following steps: firstly, dispatching among groups; then, dispatching in groups; and finally, dispatching in queues; making a request to the kernel to modify relevant marks and switch between a dispatching way among the groups and a dispatching way in the groups when intensive I / O operation is needed to be performed on application programs, modifying an elevator algorithm bound adopted for dispatching in queues into a frequent access area. When the Intense mark of a certain group is set on 1, the priority of the equipment corresponding to the group is the highest, and the dispatching among the groups is reduced; when the Continue mark of a certain group is set on 1, queues of the group are distinguished into different queues according to the area requested by I / O, so that the I / P intensive request can be possibly completed in one queue; and when the Continue mark of a certain group is set on 1, the operation bound of the elevator dispatching algorithm in the queues is changed to head and tail, so that the intensive I / O request is accessed in a centralized manner, and therefore, the round times for elevator dispatching are reduced.

Description

technical field [0001] The invention relates to the field of linux kernel I / O scheduling, in particular to a CFQ scheduling method. Background technique [0002] With the development of the Linux operating system, applications have higher and higher requirements for high-performance IO. Since the 2.6 kernel, the number of IO scheduling algorithms in the Linux kernel has increased to four, among which the CFQ (completely fair queuing) scheduling algorithm is the most widely used. In a multi-process environment, the algorithm can ensure that each process has a fair scheduling opportunity and the QoS of the IO device. But when I / O-intensive requests come, the I / O performance of the algorithm will drop. First of all, because the CFQ algorithm divides devices into different groups, the inter-group scheduling adopts a weight-based time slice method. For I / O-intensive requests, it is often for a single device. At this time, the CFQ algorithm may still occur. Inter-group scheduli...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F13/20
CPCG06F13/26
Inventor 邓宇羽
Owner LANGCHAO ELECTRONIC INFORMATION IND CO LTD
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