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

[Paul]

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.. :/

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