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pci‑e zero-copy dma data transfer method

A data transmission method, PCI-E technology, applied in the direction of electrical digital data processing, instruments, etc., can solve problems such as low efficiency, increased CPU burden, etc., to achieve the effect of reducing the number of processing, reducing switching, and reducing the pressure on the CPU

Active Publication Date: 2017-08-04
NAT COMP NETWORK & INFORMATION SECURITY MANAGEMENT CENT +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In the process of data transmission, in the data source and data destination systems, a total of 2 memory copies (step 1 and step 3, except DMA) and 4 system calls occur in this method, which is inefficient and adds unnecessary burden to the CPU.

Method used

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Embodiment Construction

[0017] The present invention will be further described in detail with reference to the accompanying drawings and embodiments.

[0018] The purpose of the present invention is to improve the data transmission efficiency of PCI-E, reduce CPU pressure, and propose a zero-copy data transmission method.

[0019] Such as figure 2 As shown, the PCI-E zero-copy DMA data transmission method provided by the present invention specifically comprises the following steps:

[0020] Step 1. Allocate N blocks of physical memory of an appropriate size in the data source and data destination systems respectively, and use a doubly linked list to establish a free memory pool and a working memory pool for the N blocks of physical memory in the data source and data destination systems respectively. figure 2 The mmap in refers to the doubly linked list.

[0021] Allocate N blocks of physical memory in the data source system and N blocks of physical memory in the data destination system, and the s...

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Abstract

The invention provides a PCI-E (peripheral component interconnect-express) zero-copy DMA (direct memory access) data transmission method and belongs to the technical field of PCI-E data transmission. The method comprises the following steps: firstly allocating physical memory with a proper size to a data source system and the physical memory with the proper size to a data destination system, and respectively establishing an idle memory pool and a working memory pool for the allocated physical memory in the data source system and the allocated physical memory in the data destination system through a double linked list; directly performing data filling after acquiring idle memory from the idle memory pool when data transmission is performed between user application programs in the data source system, and transmitting data to the data destination system after the data filling; storing the received data into the working memory pool in the data destination system, and acquiring the data for use from the working memory pool by the user application programs by using corresponding APIs (application program interfaces); returning the corresponding memory to the idle memory pool after the use. According to the PCI-E zero-copy DMA data transmission method provided by the invention, the pressure of a CPU (central processing unit) is greatly relieved; system call is reduced; the switchover of user kernel space is relived for large-scale and small-data volume transmission, and the system efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of PCI-E data transmission, in particular to a zero-copy DMA data transmission method. Background technique [0002] The traditional PCI-E data transmission method is to use DMA (Direct Memory Access, direct memory access). The specific method is to allocate a piece of continuous physical memory in both the data source and data destination systems. Before starting, the user application program in the data source system is responsible for copying the data to the physical memory. The physical memory of the data source is transferred to the physical memory of the data destination system. After the DMA is completed, the application program in the data destination system is copied to the user space for use, and then the original 2 blocks of physical memory can be used for the next data transmission. figure 1 It is a schematic diagram of the traditional data transmission method: [0003] Step 1) data source syst...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F13/28
Inventor 陈训逊周游包秀国谢铭薛晨周康成周渊
Owner NAT COMP NETWORK & INFORMATION SECURITY MANAGEMENT CENT