On Tue, 1 Jun 2010 19:39:16 -0400 Chris Frey <cdfrey@xxxxxxxxxxxxxx> wrote: > Can I be sure that the usbmon binary buffers will not drop usb packets > no matter how busy my system is? No, you cannot be sure. That is because the hooks are asynchronous and cannot exert any flow control. Therefore, a sufficiently persistent driver on a system that is busy enough will always generate enough traffic to overflow any buffers, no matter how large. This is especially sad when you have Windows under a VMM and want to snoop what it's doing. The solution is to use a multicore system and only let your VM to use a subset of available CPUs. That said, the binary API permits big buffers that absorb just about any traffic spike. As long as your snooping application is efficient and you leave enough CPU and I/O on the average, you have nothing to fear. The statistic gathering in the binary API may be not up to snuff though, honestly I never tested it properly. The packet loss never was a problem for me, so I never bothered addressing it. Patches are welcome, if any. > Side question: It is odd to me that such effort has gone into limiting > the size of the usbmon text output... even to the extent that an entire > binary API was created. What is wrong with making the 32 byte size > configurable? I'm sure I'm not understanding something here. Try opening the result with unlimited strings in vi, you'll see. -- Pete -- 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
