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1answer
289 views

How does the kernel scheduler know a timeslice has passed?

In my previous question How does the kernel scheduler know how to pre-empt a process? I was given an answer to how pre-emption occurs. Now I am wondering, how does the kernel scheduler know that a ...
1
vote
2answers
458 views

How does the kernel scheduler know how to pre-empt a process?

As far as I understand, the kernel is not a process, but rather a set of handlers that can be invoked from the runtime of another progress (or by the kernel itself via a timer or something similar?) ...
2
votes
0answers
299 views

Shielding CPU from scheduler - How to move bound kernel threads from cores?

Suppose I have 4 physical cores (indexed 0-3) and I'm dedicating cores 1-3 to a shield for user applications and trying to steer all system threads onto core 0. I'm following the answers here and ...
0
votes
1answer
533 views

What happens when there is a context switch while the process is in Kernel mode?

This is my understanding: When in user mode and a trap/system call occurs, registers are saved on to the kernel stack, switch is made to kernel mode, and trap is handled and returned to user mode. ...
2
votes
1answer
258 views

Is “top” accounting for Kernel Interrupts?

I have a simple interrupt that is triggered by a GPIO-input. The IRQ only increments a variable and returns. When I turn the frequency of the interrupts up to somewhere around 10-20 kHz, the system ...
2
votes
1answer
1k views

What is the functionality of SCHED_SOFTIRQ in linux?

Who raises this softirq? Is it raised on every time tick( based on timer interrupt?) Does this make the kernel to shedule a runnable process? If yes, how does the handlers of lower priority softirqs ...
1
vote
1answer
257 views

How does handling an interrupt affects a multi-threaded user space process?

Say, I put a breakpoint (int 3 from now on) somewhere in a user space process code. One of the threads hits the breakpoint... And what happens next? My judgement is: this is an interrupt, so it is ...
2
votes
2answers
6k views

Can system calls be interrupted?

Please comment on the following sentence: On the standard Linux kernel without the rt patch, interrupts can't interrupt ongoing system calls. The reason why our machine doesn't stop working ...
4
votes
1answer
3k views

Are time interrupts always followed by a scheduler call?

When a timer interrupt occurred the ISR is called to service the interrupt. Is it okay to assume that every timer interrupt ends with a call to the scheduler on which process should continue running ...
3
votes
1answer
3k views

Are threads which are executing blocking system calls awoken by interrupts?

I've been reading a bit about threads and interrupts. And there is a sections which says that parallel programing using threads is simpler because we don't have to worry about interrupts. However, ...