Timeline for What's the policy determining which CPU handles which interrupt in the Linux Kernel?
Current License: CC BY-SA 4.0
12 events
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| Dec 1, 2024 at 19:28 | comment | added | telcoM | @FourierFlux No, I don't. I'm not even entirely sure what you mean: are you thinking about something like "once a particular interrupt has been triggered, a second triggering of the same interrupt cannot happen/must wait until the first one has been acknowledged by the interrupt handler"? | |
| Dec 1, 2024 at 17:45 | comment | added | FourierFlux | Do you know why Linux interrupts are considered blocking if multiple cores are running? | |
| Jun 22, 2019 at 16:43 | comment | added | telcoM |
And even the IRQ-affinity.txt is effectively from year 2011, so modern kernels may actually have some semi-smart default strategy to guarantee reasonable results even with a stripped-down userspace with no irqbalance.
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| Jun 22, 2019 at 16:36 | history | edited | telcoM | CC BY-SA 4.0 |
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| Jun 22, 2019 at 16:28 | comment | added | telcoM |
If I recall correctly, back when I encountered my first Linux multiprocessor systems, the IRQs definitely used to get dumped on CPU0 if irqbalance was not used. But as the multi-core CPUs became ubiquitous, obviously the kernel defaults have been updated at some point. kernel.org/doc/Documentation/IRQ-affinity.txt suggests that the kernel default is to allow all CPUs to handle IRQs.
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| Jun 22, 2019 at 15:35 | comment | added | 炸鱼薯条德里克 | I'm curious how does userspace code do this, is there any /sys file you can read/write or there's some syscall I don't know? | |
| Jun 22, 2019 at 15:27 | history | edited | telcoM | CC BY-SA 4.0 |
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| Jun 22, 2019 at 15:27 | comment | added | telcoM |
irqbalance is not a kernel process: it's a standalone binary /usr/sbin/irqbalance that can run either in one-shot mode (i.e. adjust the distribution of interrupts once as part of the boot process, and exit) or as a daemon.
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| Jun 22, 2019 at 15:20 | history | bounty awarded | devoured elysium | ||
| Jun 22, 2019 at 15:20 | vote | accept | devoured elysium | ||
| Jun 22, 2019 at 15:19 | comment | added | devoured elysium | I can see irqbalance running in my Ubuntu 16.04 LTS. | |
| Jun 18, 2019 at 15:28 | history | answered | telcoM | CC BY-SA 4.0 |