I'm reproducing the steps of Alan Ott from his ELC 2014 talk: https://elinux.org/images/6/66/Elc_2014_usb.pdf Alan reports up to 211 Mbit/sec when using 64kB transfers while I can get only around 120 Mbit/sec when using 64kB transfers. My first question is: - is the beaglebone black expected to deliver 200+ Mbit/sec over USB? It is strange that on my setup CONFIG_USB_TI_CPPI41_DMA was disabled, CONFIG_MUSB_PIO_ONLY was enabled, and even so the CPU load on the BBB was low during the transfer. Enabling CONFIG_USB_TI_CPPI41_DMA and disabling CONFIG_MUSB_PIO_ONLY made little difference. I'm running kernel 4.17.2. I could not get much from perf either. Here are some outputs from running perf on the bbb(usb client): perf trace: https://pastebin.com/3Yeu5aJw perf record -g: https://paste.ubuntu.com/p/W3tZFhg8h3/ I also made some graphs comparing different buffer sizes, and in which function my notebook(usb host) spend most of the time: https://docs.google.com/spreadsheets/d/1Es3kjsRCTtYztqAeoNU-LFsFkeBZdfga_DhezTYyggI/edit?usp=sharing Given getting more than 120 Mbit/sec is possible, ideas of what can I look for? Thanks, Peter -- Peter -- 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
