i.MX ProcessorsのトピックRe: How to work with two cores

How to work with two cores

saida — Tue, 13 Oct 2015 08:52:36 GMT

I.MX6 Community

Is it possible to run two standalone applications on i.mx6 dual lite on two cores independently at a time ?

because in my application i want to assign one application dedicated to one core and other to other core, this has to run both at a time.

can i do this way of coding in bare metal application or do i need any OS, even in OS how can i achieve this if my previous statement is not valid ?

any reference documents or manuals

Regards

Saida

Re: How to work with two cores

Yuri — Tue, 13 Oct 2015 09:08:14 GMT

Hello,

Basically it is possible – please refer to the example of the following

thread for bare-metal configuration.

https://community.freescale.com/docs/DOC-103736

As for Linux :

https://community.freescale.com/thread/376865

Have a great day,
Yuri

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Re: How to work with two cores

BiyongSUN — Tue, 13 Oct 2015 09:27:03 GMT

taskset is a linux application to do the affinity.

It could make a linux program running on the special core.

Of course you need to add the isolcpus kernel parameter to iosolate one core. At the same time you need to change the interrupt mask to avoid the interrupt in this core.

These two steps make this core dedicate for you. If you don't need this core dedicate for you. You can skip these two steps. Just ask tasket to help you.

The following is the taskset running stress test on CPU1. you can see the CPU1 is isolated and the program stess is running on this core.

taskset 2 ./stress -c 4 &

top

Mem: 58320K used, 707652K free, 0K shrd, 3784K buff, 15920K cached

CPU0: 0.0% usr 1.0% sys 0.0% nic 98.9% idle 0.0% io 0.0% irq 0.0% sirq

CPU1: 100% usr 0.0% sys 0.0% nic 0.0% idle 0.0% io 0.0% irq 0.0% sirq

CPU2: 0.0% usr 0.0% sys 0.0% nic 100% idle 0.0% io 0.0% irq 0.0% sirq

CPU3: 0.0% usr 0.0% sys 0.0% nic 100% idle 0.0% io 0.0% irq 0.0% sirq

Note: Have to point here. This is linux knowledge not i.MX. Please check the linux document for more details.

Re: How to work with two cores

saida — Thu, 15 Oct 2015 07:25:09 GMT

Thanks for you reply

its mean that OS is required for to run dedicated application to single core using tasket

is there any freescale documents for how to initialize single core to dedicated application using bare metal application ?

if OS is required what are the minimum hardware requirement for Nucleus RTOS which is from Mentor Graphics

Regards

Saida

Re: How to work with two cores

BiyongSUN — Fri, 16 Oct 2015 03:06:38 GMT

Hi Saida,

As I mentioned, it is linux programming knowledge call "linux CPU affinity"

The tool "tasket" is also use that APIs.

Using tasket to run a hello world is a bare metal or not for you?

For a core, it doesn't know what is running.

For an OS, in the schedule layer. It is "bare metal" as well.

Processor affinity - Wikipedia, the free encyclopedia

Please check the linux org for documents.