Thanks, Alan, your answers are really helpful. one more question: > It depends on what other devices are attached to the USB bus. They may > or may not require some reserved bandwidth. Is there any tool/method I can dump reserved or allocated bandwidth info of each USB device? Thanks Yunhua On Sat, Aug 22, 2020 at 1:41 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Sat, Aug 22, 2020 at 01:35:28PM -0700, yunhua li wrote: > > HI Alan Thanks for your response. > > > What is the communication speed of the camera? 480 Mb/s (USB-2), 5000 > > Mb/s (USB-3) or something else? And how much data does the camera send > > for each frame? > > It is 5000Mb/s (USB 3.0), each video frame is about 2880000, 30 fps. > > So at 500 MB/s, and with less than 5 MB/frame, the expected transfer > time for each frame is under 10 ms. 30 frames per second should be > fine. > > > > 20 - 200 seconds? That's an awfully long latency. Much longer than you > > would expect from random fuctuations; it indicates that something is > > going badly wrong. > > Sorry it is 0.02 ~ 0.2 seconds delay, when image got corrupted, > > Okay, that's more like what one might expect. > > > > It depends on what other devices are attached to the USB bus. They may > > or may not require some reserved bandwidth. > > There is no other USB device connected to the system. > > if no other USB device, and no Isochronous transaction, Bulk > > transaction (This camera) should be able to use all bandwidth, am I > > correct? > > Yes, that's right. > > Alan Stern
