libusb performance on 8.1

[Daniel O'Connor]

On 03/02/2011, at 17:26, Daniel O'Connor wrote:
> BTW do you have a feel for the latency in bulk vs iso? I currently have 5-10 msec of buffering in the hardware which I plan on increasing but I'm not sure what a reasonable amount would be :)

I increased this by a factor of 8 but I still get drop outs during disk activity.

I timed libusb_handle_events_timeout() with a timeout of 1 millisecond and it quite often exceeds this (by a significant amount)
eg..
Triggered at 1298039742
2011/02/18 14:35:27:ugsio_child: libusb took > 10msec - 32.44 ms
2011/02/18 14:35:27:ugsio_child: libusb took > 10msec - 27.19 ms
2011/02/18 14:35:27:ugsio_child: libusb took > 10msec - 25.27 ms
2011/02/18 14:35:27:ugsio_child: libusb took > 10msec - 21.83 ms
2011/02/18 14:35:36:ugsio_child: libusb took > 10msec - 48.23 ms
Error during acquisition - ERROR:305 UGSIO aborted transfer: stalled

(still using bulk transfers for now)

--
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
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