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Hello, welcome back.

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And this lesson we going to experiment with task priorities, so far we've been creating tasks with

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the same priority level.

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This time we agreed to experiment, changing the priorities and see what happens.

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I'm going to make a copy of our Task Creation Project Project's number one over here.

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I'll call this number for.

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TASC Priority's.

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Or top priority, singular is better.

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OK, I'm going to open this.

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So in this project, we had three tasks blue, red and green, and each of them had a profiler and they

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had the same priority just to refresh your memory.

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Let's see what happens when we run this.

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Remember, in each task function, we have the profiler.

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We increment in these variables.

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So we're going to observe them in the live expressions window to see the behavior, whether they are

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similar or click over here to build.

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Go to Dybbuk.

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A select number four here.

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And then OK.

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And then I'll switch.

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OK, I'll go to live expressions over here and then.

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A, you see, they have almost the same values.

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OK, we can post this, the values are almost the same, almost the same.

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Right is because they have the same priority, meaning each of them is executing the same amount of

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time, 10 milliseconds or one milliseconds based on our take rate or based on our time quanta systems,

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which we shall take a look at when we start looking at the last sentence.

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For example, if the CUENTA is set at 10 times, this means each task would execute for 10 times 10

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milliseconds.

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That's what that means after 10 a.m. is the scheduled.

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Schedules, the next task, the first task stops executing and the next one executed for 10 months as

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well.

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And then the next one, so they'll end up with the same amount of execution as we can see over here

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with our count of variables known as the task profiler.

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OK, so stop over here.

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What I'm going to do now is.

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I'm going to change the priority of task number of task green over here.

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I'm going to change the priority to to remember the smaller the number, the higher the priority.

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So changing this to priority to effectively makes this the lowest priority amongst the three.

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So click over here to run.

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And then click here, debug.

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And then switch.

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And then click here to run.

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That's right, strange.

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We have just.

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Green running.

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Oh, Green has priority of two.

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So let's see.

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OK, so, yeah, the reason Green is running is twofold.

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Oh, explain.

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So in free, the larger the number, the higher the priority.

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Unlike other time operating systems that I'm used to, I have courses on four different time operating

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systems.

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So you should bear with me when I make this confusion.

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So with free ARTUS, the larger the number, the higher the priority.

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So.

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Number two over here is essentially the largest priority number, the other tasks have task priority

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level one one, and this has level two.

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So as the highest priority number.

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Right.

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So what is happening here is that there are certain rules to the shetler, one of the rules is that

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a lower priority task cannot interrupt a higher priority task.

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What that means is as soon as your tasks stop having the same priority level they no longer operating

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in, in the timesharing mode that I explain, the time sharing mode is the mode where each of them is

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assigned a specific amount of time to execute.

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Once they are done executing, the next task is executed.

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This happens when all of them have the same priority.

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This is known as Round-Robin scheduling, but as soon as one has a priority greater than the rest,

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just I want to execute.

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Why?

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Because a lower priority task cannot overtake a higher priority task.

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And we should explain this further in theory when we look at the task states.

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Right.

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So the reason this is executing is that this is the highest priority task.

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These tasks have lower priority.

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So they cannot they cannot interrupt this task and execute.

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That is why this is the only one executed you would see over here or the others are not blue and red.

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They are just stuck in this one.

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Blue and red have a lower priority compared to green.

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OK, so we're going to increase the priority level of red and see what happens.

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We said right to two, I'm going to click over here, so now we have.

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Green and red with the same priority, blue has a lower priority, which is one click here to build.

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Click here to download onto the board.

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And then switch over here.

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And then I'll click here to run, and I can see now we have red and green running and blue, the lower

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priority cannot interrupt the higher priority, but if they have the same priority, they share that

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time amongst themselves.

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So now they are just passing the ball to each other.

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All the scheduling is the one doing this.

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The schedule is the one assigning the time to read and then to green to read and then to green because

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blue has a lower priority.

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OK, so let's see something.

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What if I increase their priority level of blue to number three such that blue is three, red is too

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green is too.

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Let's see what happens.

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I'll click here to build.

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And then a click here to get onto the board.

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And then click here to switch.

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And then click here to play, as you can see, Lou, is the only task running because it's got the highest

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priority and these ones don't have a priority equal to blue, so they cannot get any of the time.

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OK, so these are some basic stuff.

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Next, what are we going to do in?

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The next lesson is to see how to change the task priority in real time.

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Over here, the priority is assigned during the the creation of the task.

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What if, let's say read, execute and we want to drop the priority of red after we've computed something

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else.

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We'll see how to do that in real time.

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And by real time, I mean in runtime.

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That's why I should say, rather than real time.

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OK, so I'll see you in the next lesson for that.