0
votes
0answers
29 views

Why would attempts to bind affinities for rcu kthreads fail?

I am trying to get full tickless mode working on my box on Ubuntu kernel 3.10.39. I am running the following command: for i in `pgrep rcu` ; do taskset -pc 0 $i ; done It seems to work on some of ...
4
votes
2answers
93 views

How to programatically detect when a device raises an interrupt?

How to programatically detect when a device raises an interrupt? This can be when a device is connected or disconnected. And also this case: for example: when a finger is held over a fingerprint ...
1
vote
0answers
45 views

How does an X86 Linux system maintain the system time, when no NTP etc. is in play?

When an x86 Linux system is powered up and running, how does it keep track of software time? E.g. is it incrementing a software counter based on hardware interrupts from the RTC, or is there some ...
8
votes
3answers
339 views

How does make continue compilation?

I know that I can interrupt a make process anytime without having to recompile the entire source tree again. As I know, make only compiles a target if it's not compiled yet, or the source code is ...
2
votes
1answer
100 views

Why EC2 instance spends all its time in “IRQ” and what to do about it?

I have an m1.small EC2 instance that is mostly just running Apache as a web server for several simple PHP web sites (that use RDS as a database). The server is constantly with a very high load average ...
1
vote
1answer
48 views

Linux Interrupts [closed]

I'm trying to write my own interrupt controller but I'm having some difficulties finding good documentation. Where can I find some information about interrupt management in Linux? To be more ...
1
vote
1answer
352 views

High IO-APIC-fasteoi interrupt usage eth0

I believe this is due to an rsync cronjob which runs every 15 minutes. This is a RHEL 6 box running in ESXi. /proc/interrupts shows: 18: 3386804969 IO-APIC-fasteoi eth0 and the system load ...
1
vote
2answers
1k views

How to generate signal interrupt on a file descriptor in Linux?

How can I generate a signal interrupt on a file descriptor in Linux? Motivation is to generate a interrupt in userland as we have in microcontrollers. I'll have file descriptor for I/O, and want to ...
2
votes
1answer
256 views

Generate interrupts for purpose of stress testing

I'm testing the quality of a generated PWM signal on a Raspbery Pi. I would like to test how it behaves if there are lots of interrupts coming. Is there a way to fake interrupts or force 2000 ...
1
vote
1answer
210 views

What value is stored in linux xtime variable?

Whenever I print the value of /proc/interrupts the value of rtc0 in IRQ8 which is for RTC shows only 1 interrupt on CPU0. I have read that when booting the value of the xtime variable is stored from ...
2
votes
2answers
974 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 ...
2
votes
1answer
443 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 ...
2
votes
0answers
80 views

Which counter generates timer interrupts?

I did a iotop to observe the interrupts on my computer. This is the interrupt shown most often. 0 [PIC-edge time] 247 Ints/s (max: 389) I believe it's the timer interrupt, well since ...
1
vote
0answers
86 views

Further clarification as to whether interuppts are disabled in top-half handler or not [closed]

Recently I came across a note in an online post that states the following: In modern kernels, most of the differences between fast and slow interrupts have disappeared. There remains only one: ...
7
votes
2answers
6k views

How does the Linux kernel handle shared IRQs?

According to what I've read so far, "when the kernel receives an interrupt, all the registered handlers are invoked." I understand that the registered handlers for each IRQ can be viewed via ...
1
vote
0answers
207 views

Which softirq will execute if interrupt is generated on same line: preempted or new softirq?

Following is the sequence of events: interrupt generated at line 1. line 1 disable. ISR executed. Set sofirq bit 1 line 1 enable. softirq executes and suddenly interrupts come at line 1. softirq ...
3
votes
2answers
2k views

change interrupt smp_affinity

As you can see below, nvidia is sharing the intrerrupt and the interrupt is using only CPU0, how can I change the interrupt for nvidia, and how can I make it use both CPU's ? Here is an article ...
4
votes
1answer
2k views

What determines whether an interrupt is IO-APIC-edge or IO-APIC-level?

Looking at the contents of /proc/interrupts on an x86 Linux, I see that some of the interrupts are IO-APIC-edge while others are IO-APIC-level. I wonder what determines the interrupt type, is it the ...
2
votes
1answer
557 views

Is there a utility that interprets /proc/interrupts data in time?

is there something out there ? Like top is for ps
0
votes
1answer
2k views

What happens in the Top half and Bottom Half processing of Interrupts?

I would like to know more about Top half and Bottom Half processing in the Context on Interrupts. Could someone explain me the exact things happening in both scenarios.
3
votes
2answers
2k views

'fast interrupts' in Linux

as far as I know, Linux has 'fast interrupts', those that were requested with SA_INTERRUPT flag; fast interrupts are executed with all other interrupts disabled on the current CPU. But how does it ...
3
votes
2answers
1k views

re-entrency of interrupts in Linux

I was reading "Linux device drivers, 3rd edition" and don't completely understand a part describing interrupt handlers. I would like to clarify: are the interrupt handlers in Linux nonpreemptible? ...
18
votes
4answers
17k views

How is an Interrupt handled in Linux?

I just know that Interrupt is a hardware signal assertion caused in a processor pin. But I would like to know how Linux OS handles it. What all are the things that happen when an interrupt occurs?