> > > I'd rather eliminate as much overhead as possible -- I already get > > > complaints from performance fanatics about the inability of usb-storage to > > > get past 92% bus saturation (sustained), and the problem will only get > > > worse on USB 2.0 > > > > Well then you'll be glad to see a patch from me, soonish, that teaches > > the usb-storage "transport" code to use bulk queueing. That'll get the > > bandwidth utilization up as high as it can get. It won't address any of > > these highmem issues though. > > And there's the overhead of sleeping and waking a kernel thread. Larger io > requests might help, but I am not sure.
Yes, it's that sleep/wake between scatterlist segments that's creating that 92% (at 12 Mbit/sec) or about 20% (at 480 Mbit/sec :) bottleneck ... Convert those calls to use bulk queuing, and those delays vanish. - Dave _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
