Hi ychen, We have been working on this problem and have a fully working patch that we will submit to the ML shortly. We would be glad if you could give it a test and review.
Thanks, Jan > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of ychen > Sent: Tuesday, 20 March, 2018 14:20 > To: [email protected]; [email protected] > Subject: [ovs-dev] can not well distributed when use dp_hash for ovs group > > hi, > I tested dp_hash for ovs group, and found that dp_hash can not well > distributed, some buckets even can not be selected. > In my testing environment, I have 11 buckets: > group_id=131841,type=select,selection_method=dp_hash, > bucket=bucket_id:51162,weight:100,actions=ct(commit,table=70,zone=2,exec(move:NXM_OF_ETH_SRC[]- > >NXM_NX_CT_LABEL[0..47],nat(dst=10.204.8.29:80))), > bucket=bucket_id:42099,weight:100,actions=ct(commit,table=70,zone=2,exec(move:NXM_OF_ETH_SRC[]- > >NXM_NX_CT_LABEL[0..47],nat(dst=10.204.8.25:80))), > bucket=bucket_id:53526,weight:100,actions=ct(commit,table=70,zone=2,exec(move:NXM_OF_ETH_SRC[]- > >NXM_NX_CT_LABEL[0..47],nat(dst=10.204.8.27:80))), > bucket=bucket_id:12221,weight:100,actions=ct(commit,table=70,zone=2,exec(move:NXM_OF_ETH_SRC[]- > >NXM_NX_CT_LABEL[0..47],nat(dst=10.204.8.40:80))), > bucket=bucket_id:2787,weight:100,actions=ct(commit,table=70,zone=2,exec(move:NXM_OF_ETH_SRC[]- > >NXM_NX_CT_LABEL[0..47],nat(dst=10.204.8.26:80))), > bucket=bucket_id:18951,weight:100,actions=ct(commit,table=70,zone=2,exec(move:NXM_OF_ETH_SRC[]- > >NXM_NX_CT_LABEL[0..47],nat(dst=10.204.8.24:80))), > bucket=bucket_id:32559,weight:100,actions=ct(commit,table=70,zone=2,exec(move:NXM_OF_ETH_SRC[]- > >NXM_NX_CT_LABEL[0..47],nat(dst=10.204.8.62:80))), > bucket=bucket_id:35550,weight:100,actions=ct(commit,table=70,zone=2,exec(move:NXM_OF_ETH_SRC[]- > >NXM_NX_CT_LABEL[0..47],nat(dst=10.204.8.43:80))), > bucket=bucket_id:9026,weight:100,actions=ct(commit,table=70,zone=2,exec(move:NXM_OF_ETH_SRC[]- > >NXM_NX_CT_LABEL[0..47],nat(dst=10.204.8.57:80))), > bucket=bucket_id:26811,weight:100,actions=ct(commit,table=70,zone=2,exec(move:NXM_OF_ETH_SRC[]- > >NXM_NX_CT_LABEL[0..47],nat(dst=10.204.8.34:80))) > > > But about 3~5 buckets can not be selected always. > > > In the function xlate_dp_hash_select_group(), I found the code: > uint32_t mask = (1 << log_2_ceil(n_buckets)) - 1; > uint32_t basis = 0xc2b73583 * (ctx->xin->flow.dp_hash & mask); > uint32_t score = (hash_int(bucket->bucket_id, basis) & 0xffff) * > bucket->weight; > > > for the above formula, if n_buckets is 11, then there are totally 16 > probabilities for basis. > so how can we make sure the best score can well distributed in the 11 buckets? > > _______________________________________________ > dev mailing list > [email protected] > https://mail.openvswitch.org/mailman/listinfo/ovs-dev _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
