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    SubjectRe: [PATCH RFC] USB: Add HCD fastboot
    On Fri, August 8, 2008 10:24, Rene Herman wrote:
    > On 06-08-08 20:40, Simon Arlott wrote:
    >>>> Ok - so there could be some big improvements to be had by making the
    >>>> hcd init happen as early as possible and the device initcalls later?
    >>> Maybe. Perhaps a better approach would be to make the device driver
    >>> initcalls before there are any devices for their probe routines to
    >>> block on.
    >> What about this?
    >> The Makefiles become a bit messy, but by moving things around I get the
    >> desired effect without splitting their initcalls.
    >> [ 7.941890] Write protecting the kernel read-only data: 5656k
    >> [ 5.437709] Write protecting the kernel read-only data: 5656k
    >> 2.5s faster, which is almost half the boot time.
    >> Signed-off-by: Simon Arlott <>
    > Interesting... I haven't been able to get stable improvements, with all
    > USB kernel modules built-in, just a USB mouse on OHCI and otherwise a
    > switched of USB HD on EHCI and usb-storage, but I do get the idea that
    > with your parch, I "get lucky" more often.

    It does depend on what else is running... I have e1000 (500ms) and
    sata_nv (2200ms) so there's plenty of additional time for usb devices
    to finish initialising.

    > I have knfsd as a module and it loads through the exportfs trigger
    > during bootup and outputs the last message to my dmesg:
    > 4 boots without your patch: 6.12, 6.41, 6.38, 6.34 seconds
    > 4 boots with : 5.39, 6.33, 5.37, 6.34
    > Booting with the external HD switched on adds a tiny bit to the actual
    > kernel startup time -- completely repeatable 2.62 seconds until freeing
    > init code with the HD off versus 2.73 with it on -- but doesn't seem to
    > change the picture otherwise...

    usb-storage by default delays 2 seconds before trying to use the device,
    so it won't add much time itself if there's already an driver initcall
    trying probe for devices it supports.

    > Would those results make sense you feel? I'm not looking forward to
    > putting an actual statistical analysis on it ;-)

    I suggest adding initcall_debug=1, it'll show how long the usb and other
    initcalls take to run. You should see the first usb device driver initcall
    take a second or two to run (without the patch). Maybe I'm just badly
    affected by having HCDs with 10 ports (of which only 4 are physically

    dmesg|grep initcall\
    |sed -e 's/.*initcall \([^ ]\+\( \(\[[^]]\+\]\)\)\?\) returned [^ ]\+ after \([^ ]\+\) secs/\4 \1/'\
    |sort -n

    Simon Arlott

     \ /
      Last update: 2008-08-08 13:33    [W:0.027 / U:0.496 seconds]
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