Method and system for accessing critical region

Abstract

The invention relates to two methods for accessing critical areas, wherein it comprises: presetting the write priority identifier to instruct if there is write process waiting; when CPU is ready to write data into critical area, if present critical area has read lock and the write priority identifier instructs there is not write process waiting, setting the write priority identifier as there is write process waiting; when the read lock is released, setting the write priority identifier as there is no write process waiting, and entering into critical area; when CPU is ready to read out data from critical area, and if the write priority identifier detects write process waiting, the write process has priority. The invention discloses two systems that access critical area, which comprises: CPU, read-write lock module and write priority identifier memory module. The invention can on time response the write operation of critical area, to meet high real time property of write operation in multi-core system.

Description

technical field [0001] The invention relates to the technical field of data communication, in particular to a method and a system for accessing a critical area in a multi-core system. Background technique [0002] In a multi-core system, a spin lock (Spinlock) is used to realize the requirement of multiple central processing units (CPUs) to run concurrently and mutually exclusive access to critical resources. Read write lock (read write lock) is a deformation of spin lock, spin lock can only have one process at a time: the read process or write process enters the critical area, the operation of the critical area is a serial operation, and the read write lock In other words, the read process can be executed concurrently, but the write process is not allowed to execute concurrently. During the execution of the read process or the write process, the other process is not allowed to execute, that is: the read process and the write process cannot be executed at the same time. [...

AI Technical Summary

Problems solved by technology

[0021] It can be seen that when the CPU wants to read data from the critical section, if the critical section has a read lock, the reading process can still enter the critical section. If the critical section has a write lock, the reading process must wait until the write lock is released. To enter the critical area; when the CPU wants to write data to the critical area, no matter whether the critical area has a read lock or a write lock, it must wait until the read-write lock is completely released before the writing process can enter the critical area. Yes: When the lock value of the read-write lock in the critical section is not 0, if there are continuous requests from the reading process that requires to read data from the critical section, the writing process that requires to write data to the critical section must wait all the time. The writing process cannot enter the critical section until the lock value of the read-write lock is 0. When the writing process is urgent, such as: when the administrator wants to perform a write operation with high real-time requirements on the multi-core system, this requirement cannot be met.

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