On 01/12/2018 01:19 AM, Kieran Bingham wrote: > The Linux UVC driver has long provided adequate performance capabilities for > web-cams and low data rate video devices in Linux while resolutions were low. > > Modern USB cameras are now capable of high data rates thanks to USB3 with > 1080p, and even 4k capture resolutions supported. > > Cameras such as the Stereolabs ZED (bulk transfers) or the Logitech BRIO > (isochronous transfers) can generate more data than an embedded ARM core is > able to process on a single core, resulting in frame loss. > > A large part of this performance impact is from the requirement to > ‘memcpy’ frames out from URB packets to destination frames. This unfortunate > requirement is due to the UVC protocol allowing a variable length header, and > thus it is not possible to provide the target frame buffers directly. > > Extra throughput is possible by moving the actual memcpy actions to a work > queue, and moving the memcpy out of interrupt context thus allowing work tasks > to be scheduled across multiple cores. > > This series has been tested on both the ZED and BRIO cameras on arm64 > platforms, however due to the intrinsic changes in the driver I would like to > see it tested with other devices and other platforms, so I'd appreciate if > anyone can test this on a range of USB cameras. > > In particular, any iSight devices, or devices which use UVC to encode data > (output device) would certainly be great to be tested with these patches. > > v2: > - Fix race reported by Guennadi > > v3: > - Fix similar race reported by Laurent > - Only queue work if required (encode/isight do not queue work) > - Refactor/Rename variables for clarity > > Kieran Bingham (6): > uvcvideo: Refactor URB descriptors > uvcvideo: Convert decode functions to use new context structure > uvcvideo: Protect queue internals with helper > uvcvideo: queue: Simplify spin-lock usage > uvcvideo: queue: Support asynchronous buffer handling > uvcvideo: Move decode processing to process context > > drivers/media/usb/uvc/uvc_isight.c | 4 +- > drivers/media/usb/uvc/uvc_queue.c | 114 +++++++++++++---- > drivers/media/usb/uvc/uvc_video.c | 198 ++++++++++++++++++++++-------- > drivers/media/usb/uvc/uvcvideo.h | 56 +++++++- > 4 files changed, 296 insertions(+), 76 deletions(-) > > base-commit: 6f0e5fd39143a59c22d60e7befc4f33f22aeed2f Hi, Tested on x86_64, Linux 4.15-rc8 + these 9 patches, with 3 UVC webcams. 1. usb 1-1.3: Product: Dynex 1.3MP Webcam usb 1-1.3: Manufacturer: Dynex uvcvideo: Found UVC 1.00 device Dynex 1.3MP Webcam (19ff:0102) 2. uvcvideo: Found UVC 1.00 device 2SF001 (0bda:58f5) (builtin on Toshiba laptop) 3. usb 1-1.3: New USB device found, idVendor=0c45, idProduct=62c0 usb 1-1.3: New USB device strings: Mfr=2, Product=1, SerialNumber=3 usb 1-1.3: Product: USB 2.0 Camera usb 1-1.3: Manufacturer: Sonix Technology Co., Ltd. usb 1-1.3: SerialNumber: SN0001 uvcvideo: Found UVC 1.00 device USB 2.0 Camera (0c45:62c0) BTW, qv4l2 was very useful for this. Thanks, Hans. Tested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> -- ~Randy
