Stack Overflow
Stack Overflow

Questions tagged [preemption]

131 questions
3
votes
2 answers

C#, thread priorities, and locks

In C#, if a high priority task is ready to execute and another (low priority) thread is already inside a monitor, would the low priority task be preempted in the following two scenarios: the higher priority task wants to acquire one (or more) locks…
user1258126
  • 301
  • 1
  • 13
2
votes
3 answers

basic multithreading

I have the following Interview question: class someClass { int sum=0; public void foo() { for(int i=0; i<100; i++) { sum++ } } } There are two parallel threads running through the foo method. the…
mary
  • 869
  • 5
  • 13
  • 26
2
votes
2 answers

Snakemake: Job preemption can interrupt running jobs on clusters, how to make sure that the task is not considered as failed?

I'm using Snakemake on a cluster, and I don't know how best to handle the fact that some jobs can be preempted. For more power on the cluster I use, it is possible to have access to the resources of other teams, but with the risk of being preempted,…
Thomas Bigot
  • 21
  • 2
2
votes
1 answer

kubernetes pending pod priority

I have the following pods on my kubernetes (1.18.3) cluster: NAME READY STATUS RESTARTS AGE pod1 1/1 Running 0 14m pod2 1/1 Running 0 14m pod3 0/1 Pending 0 14m pod4 0/1 …
Zsolti Vagyok
  • 55
  • 1
  • 6
2
votes
1 answer

Using podAntiAffinity rules to ensure pods run on different pre-emptible nodes

I have a 3-node cluster running on GKE. All the nodes are pre-emptible meaning they can be killed at any time and generally do not live longer than 24 hours. In the event a node is killed the autoscaler spins up a new node to replace it. This…
harryg
  • 23,311
  • 45
  • 125
  • 198
2
votes
1 answer

SLURM QOS Preemption

I was trying to setup a preemption in my SLURM 19.05 cluster, but I could not figure out how to make preemption work like what I planned. Basically, I have two QOS. $ sacctmgr show qos format=name,priority,preempt Name Priority …
Woody
  • 612
  • 9
  • 21
2
votes
0 answers

Undesired latency when kernel thread does more communication work

We have developed a kernel module that acts basically like a wired communication traffic (eth, ...) - WiFi bridge. It forwards periodically incoming wired data to WiFi and vice versa. The system consists of two devices running the same kernel…
user2818825
  • 73
  • 5
2
votes
1 answer

How to stop Pepper robot from preempting its tablet?

I'm trying to create a program, a part of which will transmit real-time video in frames (or in other words images) from my PC's webcam to Pepper's tablet using naoqi Python SDK. On the robot's side there will be a program using ALTabletService's…
androadi
  • 25
  • 7
2
votes
2 answers

Why kernel preemption is safe only when preempt_count == 0?

Linux kernel 2.6 introduced a new per-thread field---preempt_count---which is incremented/decremented whenever a lock is acquired/released. This field is used to allow kernel preemption: "If need_resched is set and preempt_count is zero, then a more…
Simple.guy
  • 362
  • 3
  • 15
2
votes
0 answers

Huge Difference in magnitude of getCurrentThreadCpuTime diff and System.nanoTime() diff for a code snippet in Java

ThreadMXBean threadBean = ManagementFactory.getThreadMXBean(); long startCPUTime = threadBean.getCurrentThreadCpuTime(); long startTime = System.nanoTime(); // Some Java Code (No Network/Database calls) ..... long endCPUTime =…
insanely_sin
  • 986
  • 1
  • 14
  • 22
2
votes
3 answers

How to limit the execution time of a function in C/POSIX?

Similar to this question, I'd like to limit the execution time of a function--preferably with microsecond accuracy--in C. I imagine that C++ exceptions could be used to achieve a result similar to this Python solution. Though it's not ideal, such an…
troutwine
  • 3,721
  • 3
  • 28
  • 62
2
votes
2 answers

Context switches in control paths of a non-preemptive kernel (Linux)

The Linux kernel is non-preemptive, but I just read that there could be context-switches in different control paths. Doesn't that contradict the non-preemptive nature on the Linux kernel?
EpsilonVector
  • 3,973
  • 7
  • 38
  • 62
2
votes
2 answers

Can the scheduler or some critical kernel threads be preempted in a preemptible Linux kernel?

Can the scheduler or some critical kernel threads be preempted in a preemptible Linux kernel? What about in an interrupt handler (top half or bottom half)?
WindChaser
  • 960
  • 1
  • 10
  • 30
2
votes
1 answer

why spin_lock_irqsave needs to disable preemption on multiprocessor

Just curious why spin_lock_irqsave needs to disable the preemption after disabling local interrupt. static inline unsigned long __raw_spin_lock_irqsave(raw_spinlock_t *lock) { unsigned long flags; local_irq_save(flags); …
eric chen
  • 21
  • 3
2
votes
3 answers

C# controlling threads (resume/suspend)

I'm trying to simulate (very basic & simple) OS process manager subsystem, I have three "processes" (workers) writing something to console (this is an example): public class Message { public Message() { } public void Show() …
Vladislav Bolshakov
  • 191
  • 14
1 2
3
…
8 9