Re: TSC instead of ACPI: powerd doesn't work anymore (to be expected?)

From: John-Mark Gurney (gurney_j_at_resnet.uoregon.edu)
Date: 10/30/05

  • Next message: Alexander Leidinger: "Re: 1kHz noise from C3 sleep" 
    Date: Sun, 30 Oct 2005 11:59:36 -0800
To: Scott Long <scottl@samsco.org>

    Scott Long wrote this message on Sun, Oct 30, 2005 at 07:30 -0700:
    > >Correct, but why is it felt the latency of the ACPI timer is an issue?
    > >Of course we all want things to as fast as possible, but is that just an
    > >abstract desire, or a real issue was run into?
    > >
    >
    > ACPI-fast requires an ioport read which takes about 1us (according to
    > Google). Do that 1000 times a second and you have each CPU spending
    > 1% of its time doing nothing but reading the clock. Yikes.

    Math correction: .1%... 1us * 1000 = 1ms, 1ms = .001s, .001 * 100% = .1% 

    -- 
  John-Mark Gurney				Voice: +1 415 225 5579
     "All that I will do, has been done, All that I have, has not."
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