OVS uses a set of gentle mechanisms to control the number of flows in datapath. However, it is difficult for the number of datapath flows to reach a high level in a short time.
Through some tests with Apache benchmark, I found the point is that the value of flow-limit increases too slowly, but decreases very quickly. This change has two improvements. One is the flow-limit will adjust more linearly. The other one is, when the duration is small, the flow-limit will increase faster. Through this change, the test result of Apache benchmark can reach 12k from 5k, the test command is as follows: ab -n 200000 -c 500 -r http://1.1.1.2/ v1->v2: Make flow-limit changes linearly. Add a limitation to make flow_limit won't overflow UINT_MAX. Signed-off-by: Tao YunXiang <taoyunxi...@cmss.chinamobile.com> Cc: Ben Pfaff <b...@ovn.org> --- ofproto/ofproto-dpif-upcall.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c index ccf97266c..805409165 100644 --- a/ofproto/ofproto-dpif-upcall.c +++ b/ofproto/ofproto-dpif-upcall.c @@ -963,14 +963,20 @@ udpif_revalidator(void *arg) duration = MAX(time_msec() - start_time, 1); udpif->dump_duration = duration; - if (duration > 2000) { - flow_limit /= duration / 1000; - } else if (duration > 1300) { - flow_limit = flow_limit * 3 / 4; - } else if (duration < 1000 && - flow_limit < n_flows * 1000 / duration) { - flow_limit += 1000; + + /* Use duration as a reference, adjust the value of flow_limit, + * when the duration is short, increase the flow_limit, and vice + * versa. The purpose of using multiple conversions between int + * and float is to make the flow_limit change more linear. */ + + if (duration >= 1000) { + flow_limit = (int) ((float) (flow_limit) / (duration / 1000.0)); + } else if (flow_limit * (1000.0 / duration) >= UINT_MAX) { + flow_limit = ofproto_flow_limit; + } else { + flow_limit = (int) (flow_limit * (1000.0 / duration)); } + flow_limit = MIN(ofproto_flow_limit, MAX(flow_limit, 1000)); atomic_store_relaxed(&udpif->flow_limit, flow_limit); -- 2.17.1 _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev