I've been looking at the issue of multiqueue RSS hashing in ixgbe (and presumably igb), which is one of the things libzero is supposed to help with.
The problem is that (at least in some cases) traffic from X->Y may end up in a different queue, and therefore different CPU core, to that from Y->X. I found some patches that are supposed to help http://www.mail-archive.com/[email protected]/msg04364.html and http://kerneltrap.org/mailarchive/linux-netdev/2010/12/18/6292110 So it appears that the hashing algorithm can be modified in the driver! In the ensuing discussion on kerneltrap.org http://kerneltrap.org/mailarchive/linux-netdev/2011/1/3/6292774 the author says that when flow-director is enabled, the patch isn't needed. So if I turn on "ntuple" with "ethtool -K eth1 ntuple: on", with no filtering rules, would that mean the queues now match? My testing has been pretty inconclusive. Certainly, even in the default modes, I get *some* traffic where X->Y and Y->X are in the same queue, but of course you'd probably expect that to happen in 1/N cases for N queues. Best Wishes, Chris -- --+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+- Christopher Wakelin, [email protected] IT Services Centre, The University of Reading, Tel: +44 (0)118 378 2908 Whiteknights, Reading, RG6 6AF, UK Fax: +44 (0)118 975 3094 _______________________________________________ Ntop-misc mailing list [email protected] http://listgateway.unipi.it/mailman/listinfo/ntop-misc
