Re: [libusb] Issues with low CDC_ACM throughput on STM32 USB-FS (sync/async)

[Xiaofan C. <xia...@gm...>]

I mean to say get rid of the Interrupt IN endpoint. You also need to change
the USB descriptors and a bit of the firmware source codes to make it a
generic USB device.

On Sat, Apr 27, 2024, 14:19 Xiaofan Chen <xia...@gm...> wrote:

> On Sat, Apr 27, 2024 at 1:54 PM Jerri Lipp via libusb-devel
> <lib...@li...> wrote:
> >
> >
> > ST's USB middleware supports double-buffering and enabled by default. I
> verified
> >  that the proper IFDEF branch is taken during compilation.
> >
> > Also, the issue is not that I'm not getting good throughput, but that in
> order to
> > approach that 1MB/s mark I have to add phantom IN transfers on one
> computer,
> > and (now that I've checked) that performance is actually worse on a much
> newer
> > and more powerful laptop.
>
> Get rid of the IN endpoint and make the device a generic USB device
> (with Bulk IN
> and Bulk OUT endpoint only), then use libusb again to see if that helps.
>
> You may also want to give libusbK kBench a try to see how fast you can get
> by testing the Bulk OUT endpoint only. Unfortunately there is no similar
> example for libusb yet.
>
> Reference:
> https://github.com/libusb/libusb/issues/962
> https://github.com/libusb/libusb/issues/951
>
> I have no issues to get >1000KB/sec for a full speed USB device
> (Microchip USB PIC) and >3Gbps with CyUSB FX3 SuperSpeed
> device
>
> I remember that Travis has done some benchmarks for STM32
> device as well and the result is also >1000KB/sec.
>
> FW source codes:
> https://github.com/mcuee/libusbk/tree/master/BmFW
>
> kBench source code
> https://github.com/mcuee/libusbk/tree/master/libusbK/src/kBench
>
> Reference discussion:
>
> https://community.osr.com/t/benchmarking-winusb-libusbk-and-cypress-cyusb-driver/57390/3
>
> 437,800 KB/sec for cyusb3.sys using Cypress Cystream application
> 437,700 KB/sec for libusb0.sys using libusbk kBench application
> 386,600 KB/sec for libusbk.sys using libusbk kBench application
> 385,300 KB/sec for WinUSB using libusbk kBench application
>
> You can also use libusb based libusbdotnet benchmarkcon example (v2
> branch only).
> https://github.com/LibUsbDotNet/LibUsbDotNet/issues/137
>
> I tested with Cypress USB FX2LP and CyUSB FX3 there. It works well for
> Bulk IN/OUT transfer, but not ISOC transfer.
>
>
> --
> Xiaofan
>