> On Sep 22, 2014, at 5:15 PM, Adrian Chadd <adr...@freebsd.org> wrote: > > On 22 September 2014 13:39, Elof Ofel <elof...@hotmail.com> wrote: >> Hi Adrian! >> >> Now this sounds promising! All my sensors use the ixgbe driver. >> However, my skills in programming/compiling isn't vast. I know how to patch >> and use poudriere. That's about it. >> >> I must admit I don't really understand what you mean with "patch it to use a >> symmetric RSS key", but it sounds like the functionality I'm looking for is >> not yet there in the driver. > > A few years ago a couple of researchers figured out you could abuse > the toeplitz hash to do symmetric RSS hashing: > > http://www.ndsl.kaist.edu/~shinae/papers/TR-symRSS.pdf > > This means that the same RSS hash value is chosen no matter which > direction the traffic is going on. > This is what you need to ensure that the packets going both directions > in a connection end up in the same NIC hardware receive ring. > > So, all you have to do (!) is: > > * grab freebsd-head, because the ixgbe driver there has some recent > bug fixes that you need for this to completely work; > * look at ixgbe_initialise_rss_mapping() - that's where the RSS key, > mapping and RSS hash types are configured; > * patch it to use the example symmetric RSS key that was provided in the > paper;
possible that XOR-ing the values to be hashed will produce a similar result. Of course, this is software, not hardware generation of Toeplitz. > * patch it to only hash on IPv4 / IPv6 2-tuple, that way you don't end > up with IPv4/IPv6 fragments in the wrong queue; I hope these two aren’t embedded in the code. The coming Intel devices both support the symmetric RSS key and will correctly hash on ipv4/ipv4 4 tuple. See section 7.1.10.1 and 7.1.10.3 in http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/xl710-10-40-controller-datasheet.pdf > * configure up say, 4 or 8 rings in /boot/loader.conf: > > hw.ix.num_queues=8 > (I think it's hw.ix, it used to be hw.ixgbe..) > > * then, when you use netmap on ixgbe, you just bind to each TX and RX > ring with a separate process or thread. That thread will get packets > in both directions for a given flow. > >> If we assume that someone in the future write and submit the above into the >> ixgbe driver, could I be so bold as to ask you for a >> commandline/configuration example (a brief guide) of how one would setup >> netmap and how to configure it to use the RX-queues? > > I don't know of any examples of using netmap in this way from the > command line. I've normally written C code (And when I do, i start > with the bridge example in src/tools/tools/netmap/bridge.c) . > >> That way I can start playing around with netmap and learning it while I wait >> for the ixgbe driver to be updated... I've got two professional programmer >> colleagues who've dealt extensively with e.g. the libnids and pfring source >> code, so if I get a grasp of how to setup netmap, and I find it interesting, >> it is likely that they can dive into and fix the ixgbe driver and improve it >> as per above. So please, can you help me with a "netmap guide"? >> >> When I try to find documentation or examples of how to setup netmap I find >> none. Not even the netmap-enabled pcaplib contain any information as how to >> use it. I'm no programmer, so showing me different C structs for delivering >> data is of no use. :-/ > > You mean: > > https://code.google.com/p/netmap-libpcap/ > > ? > > I've not used it before, sorry :( > > > > -a > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org" _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
