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This article mainly introduces how to use the Affinity of SMP in vxworks. It is very detailed and has certain reference value. Friends who are interested must finish reading it.

CPU Affinity, which is generally translated as the affinity or affinity of CPU, is a technology in multicore OS, which refers to the ability to bind a task to a CPU. In VxWorks's SMP, by default each task can be performed on each CPU, but after you specify Affinity, you can pin down certain tasks to be executed only on a specific CPU. The related functions are taskCpuAffinitySet () and taskCpuAffinityGet ()

Related to cpuset_t, there are also several macros. You can guess what it means by looking at the name, and the macro definition is also very simple ↘.

What if you don't specify Affinity? The newly created task inherits the Affinity of the Parent task. Look at an example.

What if the Affinity of a task is assigned to a CPU, and that CPU has been busy with a higher priority task that can't be executed by 01:30? VxWorks's SMP also provides a special feature: retain CPU. It is the task of this CPU to run only those CPU that are reserved. The parameter VX_SMP_CPU_EXPLICIT_RESERVE is also provided to exclude CPU that cannot be retained.

You can see that CPU2 (0x1 is CPU0, 0x2 is CPU1, 0x4 is CPU2... 0x80 is CPU7) is retained, and currently only task T1 is assigned to it. So, regardless of the priority of T1, as long as T1 enters the ready queue, it will be executed on CPU2.

The above is all the contents of the article "how to use the Affinity of SMP in vxworks". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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