On Thu, 2011-09-08 at 20:13 -0400, George Neville-Neil wrote: > On Sep 8, 2011, at 14:49 , Navdeep Parhar wrote: > > > On Thu, Sep 08, 2011 at 08:34:11AM -0400, John Baldwin wrote: > >> On Monday, September 05, 2011 7:21:12 am Ben Hutchings wrote: > >>> On Mon, 2011-09-05 at 15:51 +0900, Takuya ASADA wrote: > >>>> Hi, > >>>> > >>>> I implemented Ethernet Flow Director sysctls to ixgbe(4), here's a > >>>> detail: > >>>> > >>>> - Adding removing signature filter > >>>> On linux version of ixgbe driver, it has ability to set/remove perfect > >>>> filter from userland using ethtool command. > >>>> I implemented similar feature, but on sysctl, and not perfect filter > >>>> but signature filter(which means hash collision may occurs). > >>> [...] > >>> > >>> Linux also has a generic interface to RX filtering and hashing > >>> (ethtool_rxnfc) which ixgbe supports; wouldn't it be better for FreeBSD > >>> to support something like that? > >> > >> Some sort of shared interface might be nice. The cxgb(4) and cxgbe(4) > >> drivers > >> both provide their own tools to manipulate filters, though they do not > >> provide explicit steering IIRC. > > > > Both of them can filter as well as steer (and the tools let you do that). > > cxgbe(4) can do a lot more (rewrite + switch, replicate, etc.) but those > > features are perhaps too specialized to be configurable via a general > > purpose tool. > > > >> > >> We would need to come up with some sort of standard interface (ioctls?) > >> for > >> adding filters however. > > > > +1 for a standard interface. > > > > imho the kernel needs to be aware of the rx and tx queues of a NIC, and > > not just for steering. But that's a separate discussion. > > > > Well I do think this is actually all of a part. Most of us realize by now > that > high speed (e.g. 10G and higher) NICs only make sense if you can steer > traffic and > pin queues to cores etc.
Well, you can get way better than 1G performance without that. And for routers, flow hashing may be fine. But for a host, of course, steering packets properly can provide a major performance win. [...] > What this means is that we have > a failure of abstraction. Abstraction has a cost, and some of the people who > want > access to low level queues are not interested in paying an extra abstraction > cost. Abstraction has a cost, but it's not necessarily that high compared to rewriting a whole chunk of sockets code (especially if you don't actually have the source code). > I think that some of the abstractions we need are tied up in the work that > Takuya did > for SoC and some of it is in the work done by Luigi on netmap. I'd go so far > as to say > that what we should do is try to combine those two pieces of code into a set > of > low level APIs for programs to interact with high speed NICs. The one thing > most > people do not talk about is extending our socket API to do two things that I > think would > be a win for 80% of our users. If a socket, and also a kqueue, could be > pinned > to a CPU as well as a NIC queue that should improve overall bandwidth for a > large > number of our users. The API there is definitely an ioctl() and the hard > part is > doing the tying together. To do this we need to also work out our low level > story. But it would be a lot nicer if this could be done automatically. Which I believe it can - see the RFS and XPS features in Linux. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. _______________________________________________ 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"
