Hi Alan, > > > By the way, have you observed any significant improvements in peformance > > > from this patch? I don't have any experience with systems having lots of > > > USB devices attached. For that matter, does speeding up khubd make any > > > significant change to the overall boot time for a system? One wouldn't > > > think the other boot-up steps would have to wait for khubd... > > > > No, I haven't, but I have not set up a large quantity of devices to test > > it with. > > Hmm. If almost nobody is going to see any noteworthy improvement then > there doesn't seem to be much point in doing the parallel probing.
it is helpful for devices that want to upload firmware in their probe method. Getting the firmware from the firmware subsystem can take a long time (due to timeouts for example, which may be infinite, or because it is waiting for a filesystem to be mounted etc). Parallel probing keeps the rest of the USB subsystem running while that device is waiting, which is particularly important if the filesystem you are waiting for is on a USB device, since otherwise it could be a deadlock! So to my mind the importance of this patch is in improving correctness (lack of deadlocks) and responsiveness (newly plugged USB devices turn up at once, even if some other device is doing a long wait in its probe method), rather than performance. Ciao, Duncan. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
