Freebsd IP Forwarding performance (question, and some info) [7-stable, current, em, smp]

Julian Elischer julian at elischer.org
Tue Jul 1 20:56:43 UTC 2008


Paul wrote:
> ULE without PREEMPTION is now yeilding better results.
>         input          (em0)           output
>   packets  errs      bytes    packets  errs      bytes colls
>    571595 40639   34564108          1     0        226     0
>    577892 48865   34941908          1     0        178     0
>    545240 84744   32966404          1     0        178     0
>    587661 44691   35534512          1     0        178     0
>    587839 38073   35544904          1     0        178     0
>    587787 43556   35540360          1     0        178     0
>    540786 39492   32712746          1     0        178     0
>    572071 55797   34595650          1     0        178     0
>  
> *OUCH, IPFW HURTS..
> loading ipfw, and adding one ipfw rule allow ip from any to any drops 
> 100Kpps off :/ what's up with THAT?
> unloaded ipfw module and back 100kpps more again, that's not right with 
> ONE rule.. :/

ipfw need sto gain a lock on hte firewall before running,
and is quite complex..  I can believe it..

in FreeBSD 4.8 I was able to use ipfw and filter 1Gb between two 
interfaces (bridged) but I think it has slowed down since then due to 
the SMP locking.


> 
> em0 taskq is still jumping cpus.. is there any way to lock it to one cpu 
> or is this just a function of ULE
> 
> running a tar czpvf all.tgz *  and seeing if pps changes..
> negligible.. guess scheduler is doing it's job at least..
> 
> Hmm. even when it's getting 50-60k errors per second on the interface I 
> can still SCP a file through that interface although it's not fast.. 
> 3-4MB/s..
> 
> You know, I wouldn't care if it added 5ms latency to the packets when it 
> was doing 1mpps as long as it didn't drop any.. Why can't it do that? 
> Queue them up and do them in bigggg chunks so none are dropped........hmm?
> 
> 32 bit system is compiling now..  won't do > 400kpps with GENERIC 
> kernel, as with 64 bit did 450k with GENERIC, although that could be
> the difference between opteron 270 and opteron 2212..
> 
> Paul
> 
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