On 06/25/2015 06:18 PM, Matthew Hall wrote: > On Thu, Jun 25, 2015 at 09:14:53AM +0000, Vass, Sandor (Nokia - HU/Budapest) > wrote: >> According to my understanding each packet should go >> through BR as fast as possible, but it seems that the rte_eth_rx_burst >> retrieves packets only when there are at least 2 packets on the RX queue of >> the NIC. At least most of the times as there are cases (rarely - according >> to my console log) when it can retrieve 1 packet also and sometimes only 3 >> packets can be retrieved... > By default DPDK is optimized for throughput not latency. Try a test with > heavier traffic. > > There is also some work going on now for DPDK interrupt-driven mode, which > will work more like traditional Ethernet drivers instead of polling mode > Ethernet drivers. > > Though I'm not an expert on it, there is also a series of ways to optimize for > latency, which hopefully some others could discuss... or maybe search the > archives / web site / Intel tuning documentation. >
What would be useful is a runtime switch between polling and interrupt modes. This was if the load is load you use interrupts, and as mitigation, you switch to poll mode, until the load drops again.
