auto tuning tcp

[Alfred Perlstein]

On 11/13/12 12:25 AM, Andre Oppermann wrote:
> On 13.11.2012 09:18, Alfred Perlstein wrote:
>> On 11/13/12 12:06 AM, Andre Oppermann wrote:
>>> On 13.11.2012 07:45, Alfred Perlstein wrote:
>>>> If you are concerned about the space/time tradeoff I'm pretty happy 
>>>> with making it 1/2, 1/4th, 1/8th
>>>> the size of maxsockets.  (smaller?)
>>>>
>>>> Would that work better?
>>>
>>> I'd go for 1/8 or even 1/16 with a lower bound of 512.  More than
>>> that is excessive.
>>
>> I'm OK with 1/8.  All I'm really going for is trying to make it 
>> somewhat better than 512 when un-tuned.
> >
>>> PS: Please note that my patch for mbuf and maxfiles tuning is not yet
>>> in HEAD, it's still sitting in my tcp_workqueue branch.  I still have
>>> to search for derived values that may get totally out of whack with
>>> the new scaling scheme.
>>>
>> This is cool!  Thank you for the feedback.
>>
>> Would you like me to put this on a user branch somewhere for you to 
>> merge into your perf branch?
>
> I can put it into my branch and also merge it to HEAD with
> a "Submitted by: alfred" line.
>
Thank you, that works.  Note: it's not even compile tested at this point.

I should be able to do so tomorrow.

Are there other hashes to look at?  I noticed a few more:

UDBHASHSIZE
netinet/tcp_hostcache.c:#define TCP_HOSTCACHE_HASHSIZE          512
netinet/sctp_constants.h:#define SCTP_TCBHASHSIZE 1024
netinet/sctp_constants.h:#define SCTP_PCBHASHSIZE 256
netinet/tcp_syncache.c:#define TCP_SYNCACHE_HASHSIZE            512

Any of these look like good targets?  I think most could be looked at.  
I've only glanced.  I can provide deltas.

-Alfred