Hi Avinash, Yes, the hash function is configurable.
Are you using a DPDK release older than 2.1? In DPDK we moved away from test_hash to CRC-based hashes. Please take a look at DPDK release 2.1 examples/ip_pipeline application: in pipeline_flow_classification_be.c, we use CRC-based hash functions defined in file hash_func.h from the same folder. Regards, Cristian > -----Original Message----- > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Yeddula, Avinash > Sent: Tuesday, September 22, 2015 1:34 AM > To: dev at dpdk.org; Bly, Mike > Subject: [dpdk-dev] DPDK hash function related question > > Hello All, > > I'm DPDK extensible bucket hash in the rte_table library of packet > framework. My question is related to the actual hash function that computes > the hash signature. > > All the available examples have initialized it to test_hash. I do not see > any > hash function available in rte_table library , that computes the actual > signature > > > > struct rte_table_hash_ext_params hash_table_params = { > > .key_size = TABLE_ENTRY_KEY_SIZE, > > .n_keys = TABLE_MAX_SIZE, > > .n_buckets = TABLE_MAX_BUCKET_COUNT, > > .n_buckets_ext = TABLE_MAX_EXT_BUCKET_COUNT, > > .f_hash = test_hash, > > .seed = 0, > > .signature_offset = 0; > > .key_offset = __builtin_offsetof(struct metadata_t, tbl_key), > > }; > > > > So, I wanted to use hash functions from DPDK rte_hash library. This is what > I'm doing and looking at the code this looks ok to me. > > I'm at least a week or 2 away from testing this part of the code. I wanted to > confirm that, there is no fundamental flaw in using the DPDK rte_hash library > and rte_table library like this. Could someone confirm this please ? > > > > #define DEFAULT_HASH_FUNC rte_hash_crc > > > > struct rte_table_hash_ext_params hash_table_params = { > > .key_size = TABLE_ENTRY_KEY_SIZE, > > .n_keys = TABLE_MAX_SIZE, > > .n_buckets = TABLE_MAX_BUCKET_COUNT, > > .n_buckets_ext = TABLE_MAX_EXT_BUCKET_COUNT, > > .f_hash = DEFAULT_HASH_FUNC , > > .seed = 0, > > .signature_offset = 0; > > .key_offset = __builtin_offsetof(struct metadata_t, tbl_key), > > }; > > > > Thanks > > -Avinash >
