On Wed, 8 Aug 2007, Gabriel Maganis wrote: > Correct. I was hoping disabling preemption can keep those things > somewhat constant but looking at the list you gave, it seems the time > to travel over the cable is negligible. I am trying to see if a USB > extension cable can increase the time from my computer to the device. > Is that unlikely to be visible from a kernel module even if I use the > TSC?
No, it's not going to be visible at all. You might be able to see it with an oscilloscope or bus analyzer. IIRC the propagation speed of these signals is about 1/3 the speed of light, or roughly 10 ns per meter. In theory this is within the resolution of the TSC, but with all the other confounding factors you'd never be able to dig it out. Alan Stern ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
