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From: Florian Westphal <fw@strlen.de>
Subject: Re: [PATCH net-next 3/6] flow_dissector: Add hash_extra field to
 flow_keys struct
Date: Sun, 1 Mar 2015 20:43:48 +0100
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Tom Herbert <therbert@google.com> wrote:
> We still need hash perturbation for the mapping to a small number of
> queues which can be done after retrieving skb_get_hash, but the
> probability that two different flows match perfectly in skb_get_hash()
> should be 1/2^32-- so are hash collisions really a concern here?

I'm not concerned about accidental collisions, how predictable is skb_get_hash()?
Is skb_get_hash() guaranteed to e.g. contain L4 information?

AFAIK answer to both is "depends on nic/driver", so I feel its better to use
software flow dissector.