Re: pserialize & hw interrupt

[Ryota Ozaki <ozaki-r%netbsd.org@localhost>]

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.

  ozaki-r