Hi,
I would like to ask, what's the status of enabling Netlink MMAP in the
userspace? I'm interested to see this progressing, but digging the mail
archive I've found it run into scalability issues:
http://openvswitch.org/pipermail/dev/2013-December/034546.html
And also it can't handle frags at the moment properly:
http://openvswitch.org/pipermail/dev/2014-March/037337.html
I was thinking about this scalability issue, and I think maybe we
shouldn't stick to the 16 KB frame size. I think in most cases the
packets we are actually sending up are small ones, in case of TCP the
packets of the handshakes are less than 100 bytes. And for the rest, we
can call genlmsg_new_unicast() with the full packet size, so it will
fall back to non-mmaped communication. And this would solve the
frag-handling problem as well.
Another approach to keep the frame size lower is to pass references to
the frags, which would point outside the ring buffer, to the actual page
(which need to be mapped for the userspace). I don't know how feasible
would that be, but huge linear buffers also has to be sliced up to frags.
Regards,
Zoli
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