Re: pserialize & hw interrupt

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

On Tue, Dec 9, 2014 at 1:43 PM, Ryota Ozaki <ozaki-r%netbsd.org@localhost> wrote:
> 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.).

I couldn't get good results on this approach...

  ozaki-r