* Henning Brauer <hb-open...@ml.bsws.de> [2014-10-14 20:52]: > netmap is luigi's research framework, and he used it for some cool > research an sure will do so more in the future. no more, no less.
I should clarify: I am aware of a few use cases that profit enormously from netmap. Let's look at what netmap really is, pardon some slight inaccuracies for the sake of clarity: netmap is a ring buffer shoveling raw packets from the NIC's RX ring into userland and vice versa (to the TX ring of course). As such it is similar to BPF, but bpf does more, which is one reason why netmap is faster. Now these use cases are relatively rare; introducing yet another interface that is somewhat like an existing doesn't come for free - neither is the porting work done by sending an email to misc, nor is maintainance free. IPX and appletalk have their use cases too, and yet we deleted them - because they are to rare to justify the maintainance burden. Now if you want to spend time on improving these few use cases, that time is much better spent improving the existing interface imo - with all the existing consumers profiting. There's plenty of room without changing anything userland visible, esp. the no-filter case can probably speed up significantly without too much effort. Might even bring some ideas from netmap in (some would probably require minimal adjustments for existing consumers to profit, still way less effort than converting to a new interface). And let me repeat: all attempts to reimplement the IP stack in userland are not smart, heck, even dangerous. Not all cases fall into that category, but working w/ and in the network stack for more than a decade, I keep thinking I have a pretty good idea on what "great" ideas some people end up with. Luigi and I discussed netmap before, at length. We even mostly agree, it's for some very specific cases only. We disagree on the question whether it belongs into a general purpose OS kernel, plus, as I keep mentioning - it's not done by porting it, there is ongoing maintainance - our manpower is limited and we're not remotely out of ideas on how to improve networking for everyone. Now pardon me, beer is calling :) -- Henning Brauer, h...@bsws.de, henn...@openbsd.org BS Web Services GmbH, http://bsws.de, Full-Service ISP Secure Hosting, Mail and DNS. Virtual & Dedicated Servers, Root to Fully Managed Henning Brauer Consulting, http://henningbrauer.com/
