Date: Tue, 8 Apr 2014 09:14:25 -0400 From: John Baldwin <jhb@freebsd.org> To: Adrian Chadd <adrian@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r264250 - head/sys/dev/acpica Message-ID: <201404080914.25220.jhb@freebsd.org> In-Reply-To: <201404080236.s382aR4W057350@svn.freebsd.org> References: <201404080236.s382aR4W057350@svn.freebsd.org>
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On Monday, April 07, 2014 10:36:27 pm Adrian Chadd wrote: > Author: adrian > Date: Tue Apr 8 02:36:27 2014 > New Revision: 264250 > URL: http://svnweb.freebsd.org/changeset/base/264250 > > Log: > Add a basic set of data points which count the number of sleep entries > that are being done by the OS. > > For now this'll match up with the "wakeups"; although I'll dig deeper into > this to see if we can determine which sleep state the CPU managed to get > into. Most things I've seen these days only expose up to C2 or C3 via > ACPI even though the CPU goes all the way down to C6 or C7. No, those are actually the same thing. ACPI and Intel both use C-states for the same thing, but the numbers don't line up. That is, Intel's C6/C7 gets exposed to the OS as C2/C3 via ACPI. The 6/7 does matter, (I think) if you are using monitor/mwait as I believe the value you configure for an mwait sleep has to use Intel's number (6/7) whereas the ACPI number (2/3) is assigned by the results of _CST or whichever object it is ACPI queries. All that to say that ACPI is already using Intel's C6/C7 if you have configured your BIOS to expose it. -- John Baldwin
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