On Wed, Jul 31, 2019 at 03:08:19PM +0300, Andrew Rybchenko wrote: > On 7/25/19 7:57 AM, simei wrote: > > From: Simei Su <simei...@intel.com> > > > > Currently, there are DEFAULT,TOEPLITZ and SIMPLE_XOR hash funtion. > > To support symmetric hash by rte_flow RSS action, this patch adds > > new hash function "Symmetric Toeplitz" which is supported by some hardware. > > Isn't it a question of key to achieve symmetry? > I.e. hash algorithm (function) is still the same - Toeplitz, but > hash key makes the result symmetric (i.e. equal for flows in both > directions - swap transport ports and IPv4/6 addresses).
This is only an option when src/dst are known in advance. When doing RSS, HW implementations (such as Mellanox's) implement a modified Toeplitz XOR'ing src with dst resulting in the same hash both ways regardless of the key. -- Adrien Mazarguil 6WIND
