On Fri, Jul 21, 2017 at 10:57 AM, Stephan Müller <smueller@xxxxxxxxxx> wrote:
> Am Freitag, 21. Juli 2017, 05:08:47 CEST schrieb Theodore Ts'o:
>> Um, the timer is the largest number of interrupts on my system. Compare:
>>
>> CPU0 CPU1 CPU2 CPU3
>> LOC: 6396552 6038865 6558646 6057102 Local timer interrupts
>>
>> with the number of disk related interrupts:
>>
>> 120: 21492 139284 40513 1705886 PCI-MSI 376832-edge
>> ahci[0000:00:17.0]
>
> They seem to be not picked up with the add_interrupt_randomness function.
On x86, the local APIC timer has some special handling in
arch/x86/entry/entry_64.S that does not go through handle_irq_event().
I would assume that this is different when you boot with the "noapictimer"
option and use the hpet clockevent instead.
On other architectures, the timer interrupt is often handled as a regular
IRQ as well.
Arnd
