On Thu, Dec 19, 2019 at 09:59:48AM +0800, Ming Lei wrote: > > So pray tell, why did you not integrate this with IRQ_TIME_ACCOUNTING ? > > That already takes a timestamp and does most of what you need. > > Yeah, that was the 1st approach I thought of, but IRQ_TIME_ACCOUNTING > may be disabled, and enabling it may cause observable effect on IO > performance. Is that an actual concern, are people disabling it? > > > @@ -356,6 +512,7 @@ void irq_enter(void) > > > } > > > > > > __irq_enter(); > > > + irq_interval_update(); > > > } > > > > Arggh.. you're going to make every single interrupt take at least 2 > > extra cache misses for this gunk?!? > > Could you explain it a bit why two cache misses are involved? > > I understand at most one miss is caused, which should only happen in > irq_interval_update(), and what is the other one? The rq clock thing IIRC.
