[ovs-discuss] Isn't there any way to use RSS hash instead of jhash in flow_hash()

[Heung Sik Choi]

Hi,

In many articles about ovs, there are some mention that hashing function
cause quite significant overhead. Also, I did 'perf record' performing OVS
L3 forwarding, and found that.

So, an idea comes up, which is that implement RSS hash algorithm(Toeplitz
hash algorithm) in kernel datapath module.

However, I stucked in processing mask the 'struct sw_flow_key'.

I insert only one rule 'ovs-ofctl add-flow ovs-br1
nw_dst=100.1.1.1,actions=mod_dl_dst:90:e2:ba:5b:88:2c,in_port'.
Strangely, mac_src, mac_dst, ip_src, ip_dst, and port value in  struct
sw_flow_key is changed after calling  ovs_flow_mask_key() in
masked_flow_lookup(). I can not understand why mask processing turn on and
why mask processing change almost all values in sw_flow_key.

 Please let me know if you have any insights.
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