[ovs-discuss] flow hash calculation in open vswitch.

[Ben Pfaff]

On Wed, Apr 14, 2010 at 12:26:59AM -0400, mandar284 at aim.com wrote:
> Does all the members of struct odp_flow_key? are used in hash calculation ?

Yes.

> Can you please elaborate the parameters used in hash calculations?

The code that calculates the hash is in datapath/flow.c:

static u32 flow_hash(const struct dp_table *table,
                     const struct odp_flow_key *key)
{
        return jhash2((u32*)key, sizeof *key / sizeof(u32), table->hash_seed);
}

The only "parameter" here is table->hash_seed, which is randomly
generated when the flow table is created.