Re: Conntrack Events Performance - Multipart Messages?

[Fabian Hugelshofer <hugelshofer2006@gmx.ch>]

Patrick McHardy wrote:
> Fabian Hugelshofer wrote:
>> Patrick McHardy wrote:
>>> The first thing to try would be to use sane allocation sizes
>>> for the event messages. This patch doesn't implement it properly
>>> (uses probing), but should be enough to test whether it helps.
>>
>> Thanks a lot. This patch already decreased the CPU usage for ctevtest 
>> from 85% to 44%. Sweet...
> 
> Nice. Now we just need to do it properly :)

What do you mean with properly? Put some kind of cap? Or eliminate the 
guessing by allocating a reasonable small fixed amount?

>> nf_conntrack_event is now one of the first functions listed. Do you 
>> see other ways of improving performance?
> 
> For some members doing in-place message construction instead of
> copying the data might help, but I couldn only spot few only
> used rarely.
> 
> The module reference stuff (module_put/nf_ct_*_find_get etc)
> is clearly superfluous, this runs in packet processing context
> and shouldn't use module references but RCU.

This goes too deep, that I could help you on this.