Hi Team, Hope you all are doing good. Currently I am facing an bandwidth issue in dwc3 driver using ecm gadget with linux kernel version 4.4. I will quickly brief through my problem and the troubleshooting steps taken to debug the problem ISSUE : I have an embedded device with Qualcomm SOC and USB 3.0 support and running linux 4.4.60. I am connecting my device with Linux Host PC with linux 4.4.0-101-generic with ubuntu 16.04 distribution. We have created an USB ethernet interface now using IPERF tool we are transmitting packets from Device to Host and from Host to Device and following are our observations when MTU size is set as 15000 at both ends: Server Client Bandwidth TX QCOM Device PC 1.17 Gbps PC QCOM Device 400-500 Mbps Now when we set the MTU as 1500 then the performance received is even worst i.e from device to host the bandwidth obtained is 100 Mbps and it is observed that USB interrupts generated are too high due to which the cpu core 0 reaches 100% and cpu core 1 reaches 70%. Can you guide us to obtain high bandwidth when transmitting packets from device to host as well as reduce interrupt level and CPU usage. Troubleshooting Steps Taken : 1. Performed Iperf using TCP & UDP protocol and observed the same performance. 2. Changed all the available scaling frequencies at Device side but no improvement. 3. Using Perf profiling tool tried to debug that why interrupts are generated which causes cpu cores to 100% but did not get any breakthrough. Can you please guide me to solve this problem and attain maximum throughput of ethernet using USB 3.0 as theoretically USB 3.0 gets 5Gbps Bandwidth and here we are not able to obtain even 1Gbps Bandwidth as well. Please let me know in case of any more information required from my or any more debugging steps to be performed to narrow down the scope of problem. Hope to hear from you soon. -- Thanks & Regards, Arjav Parikh -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
