Re: workqueue for pr_input

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

On Tue, Jan 24, 2017 at 3:47 PM, Ryota Ozaki <ozaki-r%netbsd.org@localhost> wrote:
> On Mon, Jan 23, 2017 at 10:01 PM, Thor Lancelot Simon <tls%panix.com@localhost> wrote:
>> On Mon, Jan 23, 2017 at 05:58:20PM +0900, Ryota Ozaki wrote:
>>>
>>> The demerit is that that mechanism adds non-trivial
>>> overhead; RTT of ping increases by 30 usec.
>>
>> I don't see why overhead for control protocols like ICMP matters.  I
>> think if you look at longstanding commercial designs for networking
>> equipment -- software and hardware alike -- for literally decades they
>> have taken the approach of optimizing the fast path (forwarding, data
>> protocol performance) while allowing the exception/error paths (ICMP etc.)
>> to be very slow.
>
> Yes, so I proposed this approach regardless of the overhead.
>
> If none objects, I'm going to implement a complete version of my proposal
> in protosw.

Here is a patch:
  http://www.netbsd.org/~ozaki-r/workqueue-pr_input.diff

I eventually gave up implementing the mechanism in protosw; it just made
protosw complex. Instead I implemented it as helper functions (see wqinput.c).

Any comments?

  ozaki-r