Chelsio NETMAP performance

[Slawa Olhovchenkov]

I am try to use Chelsio T540-CR in netmap mode and see poor (compared
to Intel 82599ES) performance.

Same application ac receive only about 8.9Mpss, compared to 12.5Mpps
at Intel.

pmc profile show mostly time spend in:

49.76%  [17802]    service_nm_rxq @ /boot/kernel/if_cxgbe.ko
 100.0%  [17802]     t4_vi_intr
  100.0%  [17802]      ithread_loop @ /boot/kernel/kernel
   100.0%  [17802]       fork_exit


to be exact at line

        while ((d->rsp.u.type_gen & F_RSPD_GEN) == nm_rxq->iq_gen) {

Is this maximum limit for this vendor?