Re: pserialize & hw interrupt

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

On Tue, Dec 9, 2014 at 1:17 PM, Thor Lancelot Simon <tls%panix.com@localhost> wrote:
> 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?

Thank you for the suggestion. Which HZ is good for the purpose?
1000 was not good for my environment (KVM for now) and I'm trying
other HZ (500, 200, etc.).

  ozaki-r