Il giorno mar 18 mag 2021 alle ore 09:32 Kevin Bowling < kevin.bowl...@kev009.com> ha scritto:
> > > On Mon, May 17, 2021 at 10:20 AM Marko Zec <z...@fer.hr> wrote: > >> On Mon, 17 May 2021 09:53:25 +0000 >> Francois ten Krooden <f...@nanoteq.com> wrote: >> >> > On 2021/05/16 09:22, Vincenzo Maffione wrote: >> > >> > > >> > > Hi, >> > > Yes, you are not using emulated netmap mode. >> > > >> > > In the test setup depicted here >> > > https://github.com/ftk-ntq/vpp/wiki/VPP-throughput-using-netmap- >> > > interfaces#test-setup >> > > I think you should really try to replace VPP with the netmap >> > > "bridge" application (tools/tools/netmap/bridge.c), and see what >> > > numbers you get. >> > > >> > > You would run the application this way >> > > # bridge -i ix0 -i ix1 >> > > and this will forward any traffic between ix0 and ix1 (in both >> > > directions). >> > > >> > > These numbers would give you a better idea of where to look next >> > > (e.g. VPP code improvements or system tuning such as NIC >> > > interrupts, CPU binding, etc.). >> > >> > Thank you for the suggestion. >> > I did run a test with the bridge this morning, and updated the >> > results as well. +-------------+------------------+ >> > | Packet Size | Throughput (pps) | >> > +-------------+------------------+ >> > | 64 bytes | 7.197 Mpps | >> > | 128 bytes | 7.638 Mpps | >> > | 512 bytes | 2.358 Mpps | >> > | 1280 bytes | 964.915 kpps | >> > | 1518 bytes | 815.239 kpps | >> > +-------------+------------------+ >> >> I assume you're on 13.0 where netmap throughput is lower compared to >> 11.x due to migration of most drivers to iflib (apparently increased >> overhead) and different driver defaults. On 11.x I could move 10G line >> rate from one ix to another at low CPU freqs, where on 13.x the CPU >> must be set to max speed, and still can't do 14.88 Mpps. >> > > I believe this issue is in the combined txrx interrupt filter. It is > causing a bunch of unnecessary tx re-arms. > Could you please elaborate on that? TX completion is indeed the one thing that changed considerably with the porting to iflib. And this could be a major contributor to the performance drop. My understanding is that TX interrupts are not really used anymore on multi-gigabit NICs such as ix or ixl. Instead, "softirqs" are used, meaning that a timer is used to perform TX completion. I don't know what the motivations were for this design decision. I had to decrease the timer period to 90us to ensure timely completion (see https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=248652). However, the timer period is currently not adaptive. > > >> #1 thing which changed: default # of packets per ring dropped down from >> 2048 (11.x) to 1024 (13.x). Try changing this in /boot/loader.conf: >> >> dev.ixl.0.iflib.override_nrxds=2048 >> dev.ixl.0.iflib.override_ntxds=2048 >> dev.ixl.1.iflib.override_nrxds=2048 >> dev.ixl.1.iflib.override_ntxds=2048 >> etc. >> >> For me this increases the throughput of >> bridge -i netmap:ixl0 -i netmap:ixl1 >> from 9.3 Mpps to 11.4 Mpps >> >> #2: default interrupt moderation delays seem to be too long. Combined >> with increasing the ring sizes, reducing dev.ixl.0.rx_itr from 62 >> (default) to 40 increases the throughput further from 11.4 to 14.5 Mpps >> >> Hope this helps, >> >> Marko >> >> >> > Besides for the 64-byte and 128-byte packets the other sizes where >> > matching the maximum rates possible on 10Gbps. This was when the >> > bridge application was running on a single core, and the cpu core was >> > maxing out at a 100%. >> > >> > I think there might be a bit of system tuning needed, but I suspect >> > most of the improvement would be needed in VPP. >> > >> > Regards >> > Francois >> _______________________________________________ >> 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" >> > _______________________________________________ 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"
