[PATCH] Add a new TCP_IGNOREIDLE socket option

[Alfred Perlstein]

On 2/6/13 4:46 AM, John Baldwin wrote:
> On Wednesday, February 06, 2013 6:27:04 am Randall Stewart wrote:
>> John:
>>
>> A burst at line rate will *often* cause drops. This is because
>> router queues are at a finite size. Also such a burst (especially
>> on a long delay bandwidth network) cause your RTT to increase even
>> if there is no drop which is going to hurt you as well.
>>
>> A SHOULD in an RFC says you really really really really need to do it
>> unless there is some thing that makes you willing to override it. It is
>> slight wiggle room.
>>
>> In this I agree with Andre, we should not be *not* doing it. Otherwise
>> folks will be turning this on and it is plain wrong. It may be fine
>> for your network but I would not want to see it in FreeBSD.
>>
>> In my testing here at home I have put back into our stack max-burst. This
>> uses Mark Allman's version (not Kacheong Poon's) where you clamp the cwnd at
>> no more than 4 packets larger than your flight. All of my testing
>> high-bw-delay or lan has shown this to improve TCP performance. This
>> is because it helps you avoid bursting out so many packets that you overflow
>> a queue.
>>
>> In your long-delay bw link if you do burst out too many (and you never
>> know how many that is since you can not predict how full all those
>> MPLS queues are or how big they are) you will really hurt yourself even worse.
>> Note that generally in Cisco routers the default queue size is somewhere between
>> 100-300 packets depending on the router.
> Due to the way our application works this never happens, but I am fine with
> just keeping this patch private.  If there are other shops that need this they
> can always dig the patch up from the archives.
>
This is yet another time when I'm sad about how things happen in FreeBSD.

A developer come forward with a non-default option that's very useful 
for some specific workloads, specifically one that contributes much time 
and $$$ to the project and the community rejects the patches even though 
it's been successful in other OSes.

It makes zero sense.

John, can you repost the patch?  Maybe there is a way to refactor this 
somehow so it's like accept filters where we can plug in a hook for TCP?

I am very disappointed, but not surprised.

-Alfred