On Tue, Dec 03, 2013 at 01:13:15PM -0800, Greg KH wrote: > On Tue, Dec 03, 2013 at 01:08:08PM -0800, Sarah Sharp wrote: > > Yeah, it doesn't make much sense to me either. But I can reproduce the > > behavior on my Lenovo x230 if I add the PCI ID of my Intel Panther Point > > xHCI host controller to the quirk. Without the quirk, when I load the > > driver after boot with modprobe, xhci_init takes on average 44ms to > > complete. With the quirk, it takes 74ms on average. I haven't measured > > boot time too many times, but it also seems to be increased by around > > 40ms. > > > > The patch only touches the PCI and platform remove function, adding a > > host controller reset and putting the host in D3. Maybe on module > > reload, it takes longer to get the host into D0? I don't see why that > > would impact module load times at boot though. > > That might be true, try testing boot times from cold boot to get the > "real" time here. Ok, it looks like the 83353 usec module load time at cold boot I got after adding the quirk for my Panther Point xHCI host was a fluke. It's probably the D3 to D0 transition that's taking so long on module reload. I'll have to double check with the QA testers and ask them to test the boot init time, not the init time between module re-load. Results of cold boot testing, if anyone is interested: Time (in usec) to load the xHCI module on cold boot, without the quirk: 36419 35625 26464 38781 40783 267953 51562 28195 34565 34339 51891 Throwing out the 267953 usec load time, which is obviously an outlier, the average load time is 37862 usec, standard deviation is 8047 usec. Applied patch, shutdown, rebooted, and shutdown again: 35978 76865 45201 35512 46214 37151 30978 47391 38551 33239 After the patch, the average load time was 42708 usec. Not a statistically interesting increase, considering how noisy the data is. Sarah Sharp -- 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
