On Tue, Feb 04, 2020 at 12:37:08PM -0800, Navdeep Parhar wrote: > >> nm_holdoff_tmr_idx is a 0-based index into the list above. So if the > >> tmr idx is 0 you are using the 0th (first) value from the list of > >> timers. Try increasing nm_holdoff_tmr_idx and see if that brings down > >> the interrupt rate under control. > >> > >> # sysctl hw.cxgbe.nm_holdoff_tmr_idx=3/4/5 > > > > OK, interrupt rate go down, but interrupt time about same. > > (interrupt rate for intel card about 0, compared to 25% chelsio). > > I think iflib runs a lot of stuff in taskqueues rather than the driver > ithread so the CPU accounting may vary. Use dtrace to see if
Don't think this is impact: worker's CPU core w/o any syscalls and only w/ bunding workker thread and NIC irq handler show about 100% user CPU time. May be some cache-miss work performed later, at poll(2) time in case of intel driver compared to chelsio (do at interrupt time)? > netmap_rx_irq is being called by an ithread or a taskqueue to figure out > what driver does what. Can you explain some more? I am not sure about dtrace probe to use and later evaluation > Are you also transmitting a lot out of this node or is it mostly Rx? > There's no need to worry about Tx updates (and the interrupts they might > generate) if this is an Rx-mostly workload. Traffic depended. This is DDoS protection, in case of SYN-flood Tx about same as Rx. In any case Tx (as I see) is significant cheaper to Rx. x10 at least. But there are nuances in case of simultaneous. > > Most time spent in service_nm_rxq(), in while() check. > > Is this posible to do some prefetch? > > Trivial `__builtin_prefetch(64+(char*)d);` in body of loop don't > > change anything. > > > > Is this posible to do batch prefetch before cycle? > > prefetches are not possible here. That while condition is waiting for > the ownership bit of the rx descriptor to flip, indicating there is > work for the driver to do. No way to do some estimeation? Count packets pending in Rx queue? _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
