Hi! I'm trying to understand how number of "separate" rx/tx vs combined channels should be configured. I'd like to express asymmetric but mostly combined queue configuration (i.e. min(rx, tx) is combined the rest is separate). Since default number of RX queues is just 8 it is tempting to allocate 8 RX queues but num_online_cpus() TX queues. Does this configuration make sense? What should ethtool -l report?
I had a look through the drivers and it seems that most of them fall nicely into the all combined and all separate categories. Two exceptions I found are bnxt_en (recent Michael's changes) and tg3. bnxt_en can switch between combined and separate mode. tg3 is more interesting, it uses separate rx/tx parameters but combines first min(rx, tx) of the queues as I would like to. The problem is if I hijack the "separate" rx/tx queues parameters like tg3 does there is no way for the user to express that (s)he truly wants them separate. Also it seems that tg3 goes against the ethtool manual which states: > rx N Changes the number of channels with only receive queues. > tx N Changes the number of channels with only transmit queues. Which indicates that if user wants 8 rx, 12 tx and combining (s)he should do: ethtool -L ethX combined 8 tx 4 This, however, makes the max_* info from SCHANNLES quite imprecise since device which has 16 IRQs and 16 queues in each directions would probably report: max_rx: 16 max_tx: 16 max_combined: 16 But setting 'ethtool -L ethX combined 16 tx 8' would obviously fail even though parameters are within 1..max limits. Any comments/advice would be much appreciated. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
