Jason Thorpe <thor...@me.com> writes: >> On Nov 18, 2018, at 11:00 AM, Martin Husemann <mar...@duskware.de> wrote: >> >> On Sun, Nov 18, 2018 at 04:19:50PM +0530, Cherry G.Mathew wrote: >>> Typo: >>> https://mail-index.netbsd.org/source-changes/2018/11/18/msg100702.html >> >> Ugh - can't you just modify >> >> CLKF_USERMODE(frame) >> CLKF_PC(frame) >> CLKF_INTR(frame) >> >> for xen making them ignore their frame argument and use the per-cpu cached >> (but more minimal) data instead? > > +1 > > In addition to "we shouldn't even have this hardclock() interrupt > anyway", it also makes the signature of hardclock() "not like a > regular interrupt handler". >
If you mean the timing signature, Specifically in the case of xen, the clock interrupt is really randomly skewed (depending on the hypervisor scheduler algorithm, load, etc.). We even have a nice little bug where time runs backwards on the domains because our compensatory algorithms aren't able to do it perfectly. From that PoV, there's no timing signature impact. I'll work on reducing the memory copying overhead though. -- ~cherry
