Re: [PATCH 4/4] first conntrack ID must be 1 not 2

[Patrick McHardy <kaber@trash.net>]

Jozsef Kadlecsik wrote:
> On Thu, 16 Feb 2006, Patrick McHardy wrote:
> 
>>>(jiffies, tuples) would be unique even in that case.
>>
>>Thats true. But what is the advantage over using the counter?

Actually it would still not be unique if connections live
shorter than a jiffy and are resurrected.

> Currently nothing :-).
> 
> However, the counter poses an internal bottleneck in the overall system
> when one attempts to replace the hashtable by hashtrie. (What I really
> like about hashtrie is that it naturally implements the 'region locking'
> suggested by Patrick Schaaf, compared to the 'brute force' per bucket
> locking.)
> 
> As I see, we have got three bottlenecks in conntrack in SMP systems:
> the hashtable approach, the id and the expectation list. The first two
> could be eliminated by hashtrie and jiffies as ids.
> 
> Some clever solution should only be found to spread the expectations
> over multiple, separatedly locked buckets...

I've talked to Harald about this and as a start we can start by
allowing masks only for the source part of the tuple. That
means we can hash by destinations.