<meta http-equiv="Content-Type" content="text/html; charset=GB18030"><div><div><div><div><div>Hello, I used the ip_pipeline program of 18.11 dpdk and made it flow 1GB/s. I found that the 0-core CPU occupies very high (usleep has been added in the for loop of the ip_pipeline main function, which should not occupy very high CPU).Use perf to view and find that it is occupied in dw_readl.</div><div><br></div><div><b>perf situation:</b></div><div> - 61.60% 61.60% [kernel] [k] dw_readl </div><div> </div><div> + 5.89% ret_from_fork </div><div> 1.57% ordered_events__flush </div><div> + 1.25% 0xe1 </div><div> + 1.13% x86_64_start_kernel </div><div> 1.02% hist_entry_iter__add </div><div> + 1.02% 0xd1 </div><div> + 22.14% 0.00% [kernel] [k] __irqentry_text_start </div><div> + 22.11% 0.00% [kernel] [k] handle_irq </div><div> + 22.08% 0.01% [kernel] [k] handle_irq_event_percpu </div><div> + 19.31% 0.00% [unknown] [k] 0xffffffff8168dd6d </div><div> + 19.30% 0.00% [unknown] [k] 0xffffffff81698bef </div><div> + 19.28% 0.00% [unknown] [k] 0xffffffff8102d26</div><div> + 19.28% 0.00% [unknown] [k] 0xffffffff811337d</div><div> + 19.27% 0.00% [unknown] [k] 0xffffffff8113033</div><div> + 19.25% 0.00% [unknown] [k] 0xffffffff8113015</div><div> + 17.14% 0.02% [kernel] [k] i2c_dw_isr </div><div> + 14.50% 0.00% [unknown] [k] 0xffffffffa04f406</div><div><br></div><div><b>This is my hardware information:</b></div><div><br></div><div> CPU model : Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz</div><div> Network card model and version : i40e 1.5.10-k, two card</div><div> Network card firmware : 6.01 0x8000372b 0.0.0</div><div> lscpi view network card information:</div><div> 03:00.0 Ethernet controller: Intel Corporation Ethernet Controller X710 for 10GbE SFP+ (rev 02)</div><div> 03:00.1 Ethernet controller: Intel Corporation Ethernet Controller X710 for 10GbE SFP+ (rev 02)</div><div><br></div><div> Network card driver use: vfio-pci</div><div><br></div><div><b>Modified ip_pipeline main function :</b></div><div><br></div><div> /* Script */</div><div> if (app.script_name)</div><div> cli_script_process(app.script_name,</div><div> app.conn.msg_in_len_max,</div><div> app.conn.msg_out_len_max);</div><div> #include <unistd.h></div><div> /* Dispatch loop */</div><div> for ( ; ; ) {</div><div> conn_poll_for_conn(conn);</div><div> usleep(5000);</div><div> conn_poll_for_msg(conn);</div><div> kni_handle_request();</div><div> }</div><div><br></div><div><b>CLI startup parameters:</b></div><div> ./ip_pipeline -c f -- -s ./l2fwd.cli</div><div><br></div><div><b>CLI content:</b></div><div><br></div><div> mempool MEMPOOL0 buffer 2304 pool 32K cache 256 cpu 0</div><div><br></div><div> link LINK0 dev 0000:03:00.1 rxq 1 128 MEMPOOL0 txq 1 512 promiscuous on</div><div> link LINK1 dev 0000:03:00.0 rxq 1 128 MEMPOOL0 txq 1 512 promiscuous on</div><div> ;link LINK2 dev 0000:06:00.0 rxq 1 128 MEMPOOL0 txq 1 512 promiscuous on</div><div> ;link LINK3 dev 0000:06:00.1 rxq 1 128 MEMPOOL0 txq 1 512 promiscuous on</div><div><br></div><div> pipeline PIPELINE0 period 10 offset_port_id 0 cpu 0</div><div><br></div><div> pipeline PIPELINE0 port in bsz 32 link LINK0 rxq 0</div><div> pipeline PIPELINE0 port in bsz 32 link LINK1 rxq 0</div><div> ;pipeline PIPELINE0 port in bsz 32 link LINK2 rxq 0</div><div> ;pipeline PIPELINE0 port in bsz 32 link LINK3 rxq 0</div><div><br></div><div> pipeline PIPELINE0 port out bsz 32 link LINK0 txq 0</div><div> pipeline PIPELINE0 port out bsz 32 link LINK1 txq 0</div><div> ;pipeline PIPELINE0 port out bsz 32 link LINK2 txq 0</div><div> ;pipeline PIPELINE0 port out bsz 32 link LINK3 txq 0</div><div><br></div><div> pipeline PIPELINE0 table match stub</div><div> pipeline PIPELINE0 table match stub</div><div> ;pipeline PIPELINE0 table match stub</div><div> ;pipeline PIPELINE0 table match stub</div><div><br></div><div> pipeline PIPELINE0 port in 0 table 0</div><div> pipeline PIPELINE0 port in 1 table 1</div><div> ;pipeline PIPELINE0 port in 2 table 2</div><div> ;pipeline PIPELINE0 port in 3 table 3</div><div><br></div><div> thread 1 pipeline PIPELINE0 enable</div><div><br></div><div> pipeline PIPELINE0 table 0 rule add match default action fwd port 1</div><div> pipeline PIPELINE0 table 1 rule add match default action fwd port 0</div><div> ;pipeline PIPELINE0 table 2 rule add match default action fwd port 3</div><div> ;pipeline PIPELINE0 table 3 rule add match default action fwd port 2</div><div><br></div><div><b>I have done these tests</b></div><div><br></div><div> 1. Using the i40e device of E5-2620 CPU to perform the same test, there is no such problem</div><div><br></div><div> 2. I still use the i7-6700 i40e device, and I rolled back to the 18.05 version for testing, there is no such problem.</div><div><br></div><div> 3. The fallback code locates the code node that causes this problem as 4205c7ccec4fc2aeafe3e7ccf6b028d9476fccaf, this node had no problems before, and there were problems afterwards.</div><div><br></div><div> 4. I found that there are two kernel modules on this i7-6700 device: idma64, i2c_designware, when I uninstall these two modules, this phenomenon will not appear.</div><div><br></div><div> 5. I found that when there is a problem, the call frequency of an interrupt reaches tens of thousands per second! When there is no problem, the call frequency of this interrupt is 0.</div><div><br></div><div> 6. On the basis of 18.11, in the i40e_dev_start function</div><div><br></div><div> if (dev->data->dev_conf.intr_conf.rxq == 0) {</div><div> rte_eal_alarm_set(I40E_ALARM_INTERVAL,</div><div> </div><div> i40e_dev_alarm_handler, dev);</div><div> } else {</div><div> /* enable uio intr after callback register */</div><div> rte_intr_enable(intr_handle);</div><div> }</div><div><br></div><div> Change to</div><div><br></div><div> /* enable uio intr after callback register */</div><div> rte_intr_enable(intr_handle);</div><div><br></div><div> if (dev->data->dev_conf.intr_conf.rxq == 0) {</div><div> rte_eal_alarm_set(I40E_ALARM_INTERVAL,</div><div> i40e_dev_alarm_handler, dev);</div><div> }</div><div><br></div><div> Then this problem will not occur.</div><div><br></div><div>From the above scene, if I want to use the 18.11 dpdk version normally, I will either uninstall the module or add rte_intr_enable, but I don��t know what will happen if I do this? Can you answer me? Is this a bug?</div><div><br></div></div></div></div></div>