Re: pserialize & hw interrupt

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Tue, Dec 09, 2014 at 12:52:35PM +0900, Ryota Ozaki wrote:
> On Fri, Dec 5, 2014 at 10:02 AM, Ryota Ozaki <ozaki-r%netbsd.org@localhost> wrote:
> > On Fri, Dec 5, 2014 at 7:07 AM, Mindaugas Rasiukevicius
> > <rmind%netbsd.org@localhost> wrote:
> >> Ryota Ozaki <ozaki-r%netbsd.org@localhost> wrote:
> >>> Can we use pserialize for readers in hardware interrupt?
> >>> If we use splhigh instead of splsoftserial (pserialize_read_enter)
> >>> for critical sections of the readers, we can guarantee that
> >>> the readers don't touch a removed object anymore after
> >>> pserialize_perform. It this correct?
> >>
> >> It is correct, however we are trying to do less work in the hardware
> >> interrupt handlers by moving it to the software interrupts.
> >
> > Thanks. I think we need a gradual migration plan to the direction.
> 
> Anyway I wrote a patch of a softint-based interrupt handler for if_vioif:
> http://www.netbsd.org/~ozaki-r/vioif-softint-intr.diff
> 
> It works well without problems, but I see performance degradation on
> L2 forwarding. So the feature is disabled by default.

Can you try increasing HZ?

Thor