Date: Tue, 6 Mar 2012 12:46:03 +0530 From: Maninya M <maninya@gmail.com> To: freebsd-hackers@freebsd.org Subject: Re: CPUID and CPU STATE Message-ID: <CAC46K3kZCS1__ESeTkRojoi4GqWeE3AfTuz5CQkkw1bhzb4LWg@mail.gmail.com> In-Reply-To: <201203051221.08681.jhb@freebsd.org> References: <CAC46K3mS1FSy0qpze7hN6YzR_63xT9eMHUXgLJo5cjyzMz=RnQ@mail.gmail.com> <201203051221.08681.jhb@freebsd.org>
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Thank you. How do we get hardware cpuid? Can we change the number of CPUs available to the scheduler (in the scheduler code) dynamically, say completely cutting off a specific cpu core from being used at all? On 5 March 2012 22:51, John Baldwin <jhb@freebsd.org> wrote: > On Friday, March 02, 2012 2:20:00 am Maninya M wrote: > > I was unable to get this information about the cpuid variable in the > > scheduler source code. > > How does cpuid get its value from the hardware? > > The cpuid is a software ID value assigned during boot. It is not > directly related to any specific hardware IDs. > > > How is the CPUSTATES value obtained/changed with hardware in the source > > code? > > Do you mean, does cp_time[] handle hardware changes (hotplug CPUs, etc.)? > Currently that isn't supported, the kernel assumes the set of CPUs is > static for a given boot's lifetime. > > -- > John Baldwin > -- Maninya
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