Re: Restructuring ARP cache

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

On Wed, Aug 26, 2015 at 1:55 AM, David Young <dyoung%pobox.com@localhost> wrote:
> On Mon, Aug 17, 2015 at 06:23:14PM +0900, Ryota Ozaki wrote:
>> Hi,
>>
>> Here is a new patch that restructures ARP caches, which
>> aims for MP-safe network stack:
>> http://www.netbsd.org/~ozaki-r/lltable-arpcache.diff
>> (https://github.com/ozaki-r/netbsd-src/tree/lltable-arpcache)
>
> I don't think that through this piecemeal approach, NetBSD can achieve a
> maintainable, MP-safe network stack that is competitive in performance
> with the other stacks out there.
>
> To put this into the old formula, you may pick three: piecemeal,
> maintainable, MP-safe, performance.
>
> I think it's important to take several steps toward simplicity before
> anything else.  Neither simplicity nor MP-safety are compatible with a
> network stack shot through with caches like NetBSD's stack is, now.

In my plan, the next step is to separate L2 nexthop cache from the
routing table that simplifies route lookup operations. For example,
the route cloning mechanism can be eliminated. See the changes
of rtalloc1 and rtrequest1 in this PoC patch:
http://www.netbsd.org/~ozaki-r/separate-l2-nexthop.diff

  ozaki-r