On Thu, Mar 28, 2013 at 8:30 PM, B, Ravi <ravibabu@xxxxxx> wrote: > > For example, in one iteration I have observed, the time taken by uvc_video_decode_isoc() was 2175 usec. In this maximum amount of time was consumed by uvc_video_decode_data() around 1792 usec. uvc_video_decode_data() is basically a memcpy() from coherent buffer to normal buffer. > > The function uvc_video_decode_data() was called in loop, below the time taken in each iteration. The total was around 1792 usec. > > SUM(108, 59, 72, 57, 108, 58, 108, 58, > 72, 87, 72, 58, 108, 59, 82, 58, > 108,59, 72, 87, 74, 59, 109) = 1792 usec Looks that just means very slow read data from coherent buffer, or bad memcpy? Also you might need to check if you use gp_timer as default clocksource, otherwise the default 32K timer only gives you a ~30us accuracy. Thanks, -- Ming Lei -- 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
