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Thread: Enable all cores at boot-time

  1. #1
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    Enable all cores at boot-time

    I was doing a general check in dmesg for errors and i saw something that intrigued me

    "[25010.556730] Disabling non-boot CPUs ...
    [25010.660016] CPU 1 is now offline
    [25010.764009] CPU 2 is now offline"

    This assumes that at boot-time (i have a tripple core amd) the 2nd and 3rd core is down? And if so, enabeling them would make boot process faster (i am asking mainly not for my desktop but for laptop which boots kinda slow).

    Thanx.
    Last edited by editheraven; November 18th, 2012 at 09:10 PM.
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  2. #2
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    Jan 2011
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    Re: Enable all cores at boot-time

    Quote Originally Posted by editheraven View Post
    I was doing a general check in dmesg for errors and i saw something that intrigued me

    "[25010.556730] Disabling non-boot CPUs ...
    [25010.660016] CPU 1 is now offline
    [25010.764009] CPU 2 is now offline"

    This assumes that at boot-time (i have a tripple core amd) the 2nd and 3rd core is down? And if so, enabeling them would make boot process faster (i am asking mainly not for my desktop but for laptop which boots kinda slow).

    Thanx.
    25010sec / 60 min/sec= 416 min
    I agree 416 minutes is too long to be a proper boot time

    next time use

    Code:
    dmesg | head -n 1000
    those messages are mundane core sleep messages
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  3. #3
    Join Date
    Aug 2011
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    Re: Enable all cores at boot-time

    Quote Originally Posted by idoitprone View Post
    25010sec / 60 min/sec= 416 min
    I agree 416 minutes is too long to be a proper boot time

    next time use

    Code:
    dmesg | head -n 1000
    those messages are mundane core sleep messages
    I remember there used to be a concurrent command to be passed on to GRUB, wonder if thats been depreciated, that command would use all the CPU's for boot process.

  4. #4
    Join Date
    Jun 2007
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    11,131

    Re: Enable all cores at boot-time

    I'm guessing you put your system in suspend/sleep/hibernate when those messages were logged.

  5. #5
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    Re: Enable all cores at boot-time

    Quote Originally Posted by Linuxisfast View Post
    I remember there used to be a concurrent command to be passed on to GRUB, wonder if thats been depreciated, that command would use all the CPU's for boot process.
    upstart for ubuntu does uses all cores for boot

    Booting is generally io bound, so it wont make much difference if all core are active.
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  6. #6
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    Re: Enable all cores at boot-time

    Quote Originally Posted by editheraven View Post
    I was doing a general check in dmesg for errors and i saw something that intrigued me

    "[25010.556730] Disabling non-boot CPUs ...
    [25010.660016] CPU 1 is now offline
    [25010.764009] CPU 2 is now offline"

    This assumes that at boot-time (i have a tripple core amd) the 2nd and 3rd core is down?
    No, as the other poster told you these time stamps are hours after boot time, they are probably normal power saving messages as the system turns off unneeded CPUs.

    "Boot time" is the first few tens of seconds of the dmesg file.
    Regards, David.
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