Peter Zijlstra <[email protected]> writes:
> On Thu, May 07, 2020 at 11:24:49PM +0200, Thomas Gleixner wrote:
>> But over our IRC conversation I came up with a 3rd variant:
>>
>> For most of the vectors the indirect call overhead is just noise, so
>> we can run them through the ASM switcher, but for the resched IPI
>> we can just use a separate direct call stub in ASM.
>
> Are we sure the rat-poison crap is noise for all the other system
> vectors? I suppose it is for most since they'll do indirect calls
> themselves anyway, right?
We have different categories:
1) Uninteresting
SPURIOUS_APIC_VECTOR, ERROR_APIC_VECTOR, THERMAL_APIC_VECTOR,
THRESHOLD_APIC_VECTOR, REBOOT_VECTOR, DEFERRED_ERROR_VECTOR
2) Indirect call poisoned
LOCAL_TIMER_VECTOR
X86_PLATFORM_IPI_VECTOR
IRQ_WORK_VECTOR
HYPERV_STIMER0_VECTOR
HYPERVISOR_CALLBACK_VECTOR
POSTED_INTERRUPT_WAKEUP_VECTOR.
CALL_FUNCTION_VECTOR
CALL_FUNCTION_SINGLE_VECTOR
3) Quick
RESCHEDULE_VECTOR
POSTED_INTR_VECTOR
POSTED_INTR_NESTED_VECTOR
These two postit ones are weird because they are both empty and
just increment different irq counts.
HYPERV_REENLIGHTENMENT_VECTOR
schedules delayed work, i,e. arms a timer which should be
straight forward, but does it matter?
4) Others
UV_BAU_MESSAGE - The TLB flushes are probably more expensive than
ratpoutine
Hmm?
Thanks,
tglx
