busy-waiting

How do you pause a thread until a condition becomes true without busy waiting?

由 纵饮孤独 提交于 2019-12-24 22:42:55
问题 How do you pause a thread until a condition becomes true without busy waiting? For example, suppose I'm checking to see whether playerOne.isWalking() Is going to be true and I want to run some code when it does become true. Again suppose playerOne is an instance of the class Player which then has the function isWalking(). I do not have access to the what makes isWalking() become true. So everytime I want to check to see if isWalking() is true, I have to call the method from an instance of

Spinlock vs Busy wait

由 一曲冷凌霜 提交于 2019-12-04 17:53:29
问题 Please explain why Busy Waiting is generally frowned upon whereas Spinning is often seen as okay. As far as I can tell, they both loop infinitely until some condition is met. 回答1: A spin-lock is usually used when there is low contention for the resource and the CPU will therefore only make a few iterations before it can move on to do productive work. However, library implementations of locking functionality often use a spin-lock followed by a regular lock. The regular lock is used if the

Prevent MPI from busy looping

由 人走茶凉 提交于 2019-12-04 00:59:23
问题 I have an MPI program which oversubscribes/overcommits its processors. That is: there are many more processes than processors. Only a few of these processes are active at a given time, though, so there shouldn't be contention for computational resources. But, much like the flock of seagulls from Finding Nemo , when those processes are waiting for communication they're all busy-looping, asking "Mine? Mine? Mine?" I am using both Intel MPI and OpenMPI (for different machines). How can I

Threads: Busy Waiting - Empty While-Loop [duplicate]

由 旧街凉风 提交于 2019-12-01 05:34:22
问题 This question already has answers here : Is this starvation? (2 answers) Closed 5 years ago . During our lessons in the university, we learned about Threads and used the "Busy Waiting" method for an example of a Car waiting at a TrafficLight . For this task we build three classes: TrafficLight (implements Runnable) Car (implements Runnable) Main In our Main class we start two Thread s, one of Car , and one of TrafficLight . The Car has the boolean attribute hasToWait . The run() method in

What is the difference between busy-wait and polling?

由 て烟熏妆下的殇ゞ 提交于 2019-11-28 20:50:09
From the Wikipedia article on Polling Polling, or polled operation, in computer science, refers to actively sampling the status of an external device by a client program as a synchronous activity. Polling is most often used in terms of input/output (I/O), and is also referred to as polled I/O or software driven I/O. Polling is sometimes used synonymously with busy-wait polling (busy waiting). In this situation, when an I/O operation is required the computer does nothing other than check the status of the I/O device until it is ready, at which point the device is accessed. In other words the

What is the difference between busy-wait and polling?

由 佐手、 提交于 2019-11-27 13:15:16
问题 From the Wikipedia article on Polling Polling, or polled operation, in computer science, refers to actively sampling the status of an external device by a client program as a synchronous activity. Polling is most often used in terms of input/output (I/O), and is also referred to as polled I/O or software driven I/O. Polling is sometimes used synonymously with busy-wait polling (busy waiting). In this situation, when an I/O operation is required the computer does nothing other than check the

Loop doesn't see value changed by other thread without a print statement

由 不打扰是莪最后的温柔 提交于 2019-11-25 21:38:19
问题 In my code I have a loop that waits for some state to be changed from a different thread. The other thread works, but my loop never sees the changed value. It waits forever. However, when I put a System.out.println statement in the loop, it suddenly works! Why? The following is an example of my code: class MyHouse { boolean pizzaArrived = false; void eatPizza() { while (pizzaArrived == false) { //System.out.println(\"waiting\"); } System.out.println(\"That was delicious!\"); } void
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