Pinning tasks to Core for ISR

rohit269
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Joined: Mon Sep 11, 2017 4:22 am

Pinning tasks to Core for ISR

Postby rohit269 » Wed Apr 25, 2018 12:36 pm

I read the following on the ESP-IDF doc
Care should be taken when allocating an interrupt using a task not pinned to a certain core; while running code not in a critical section, these tasks can migrate between cores at any moment, possibly making an interrupt operation fail because of the reasons mentioned above. It is advised to always use xTaskCreatePinnedToCore with a specific CoreID argument to create tasks that will handle interrupts.
I'm using GPIO interrupts in separate tasks, which are not pinned to a core. And only one of them seems to be working.

Does that mean I need to pin both the tasks each to a separate core so that they can work together?

Thanks

ESP_Dazz
Posts: 308
Joined: Fri Jun 02, 2017 6:50 am

Re: Pinning tasks to Core for ISR

Postby ESP_Dazz » Sun Jul 15, 2018 5:05 pm

It means that the interrupt will be allocated to which ever core the allocation API was running on at the time. This becomes a problem when doing so from an unpinned task because the interrupt can be allocated to any core. Interrupt de-allocation must be called on the same core to which the interrupt is allocated to.
Therefore it is recommended that all interrupt allocation/de-allocation be called from a task which is pinned to a core.

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urbanze
Posts: 301
Joined: Sat Jun 10, 2017 9:55 pm
Location: Brazil

Re: Pinning tasks to Core for ISR

Postby urbanze » Sun Jul 15, 2018 7:05 pm

ESP_Dazz wrote:It means that the interrupt will be allocated to which ever core the allocation API was running on at the time. This becomes a problem when doing so from an unpinned task because the interrupt can be allocated to any core. Interrupt de-allocation must be called on the same core to which the interrupt is allocated to.
Therefore it is recommended that all interrupt allocation/de-allocation be called from a task which is pinned to a core.
What happen if you deallocated in another core? I use a task non-pinned that turns touch interrupt on and off and there have never been any problems for months. Luck? :shock:

ESP_Sprite
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Re: Pinning tasks to Core for ISR

Postby ESP_Sprite » Mon Jul 16, 2018 2:30 am

Nothing wrong with just enabling and disabling interrupts; we do that using the interrupt matrix which is shared between CPUs and as such that can be done from any CPU. If you however de-allocate an interrupt, the code needs to touch registers that are only in the CPU where the interrupt was allocated. If it can't do that, the de-alloc will fail.

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