On Thu, Jun 16, 2016 at 10:23:42AM +0000, Juan Antonio Montesinos Delgado wrote: > Hi, > > As I understand it, the hash table entry can change position in the first > hash table but the index in the second hash table remains the same. So, > regardless the bucket the entry is in, the index (of the second hash table) > stored in that entry will be the same. Am I right? > > Best, > > Juan Antonio >
Ah, yes, you are right. The key data should not move, only the hash value. I'd forgotten that. /Bruce > -----Original Message----- > From: Bruce Richardson [mailto:bruce.richardson at intel.com] > Sent: jueves, 16 de junio de 2016 11:50 > To: Yari Adan PETRALANDA <yari.adan.petralanda at ericsson.com> > Cc: pablo.de.lara.guarch at intel.com; Juan Antonio Montesinos Delgado > <juan.antonio.montesinos.delgado at ericsson.com>; dev at dpdk.org > Subject: Re: [PATCH] hash: new function to retrieve a key given its position > > On Thu, Jun 16, 2016 at 10:22:30AM +0200, Yari Adan Petralanda wrote: > > The function rte_hash_get_key_with_position is added in this patch. > > As the position returned when adding a key is frequently used as an > > offset into an array of user data, this function performs the > > operation of retrieving a key given this offset. > > > > A possible use case would be to delete a key from the hash table when > > its entry in the array of data has certain value. For instance, the > > key could be a flow 5-tuple, and the value stored in the array a time stamp. > > > > I have my doubts that this will work. With cuckoo hashing, a hash table entry > can change position multiple times after it is added, as the table is > reorganised to make room for new entries. > > Regards, > /Bruce >
