Is machdep.cpu_idle_hlt deprecated?
John Baldwin
jhb at freebsd.org
Mon May 2 14:36:35 UTC 2011
On Sunday, May 01, 2011 12:20:28 am Jeremy Chadwick wrote:
> Anyone know if machdep.cpu_idle_hlt still exists? Taken from acpi(4) on
> RELENG_8:
>
> hw.acpi.cpu.cx_lowest
> Lowest Cx state to use for idling the CPU. A scheduling algo-
> rithm will select states between C1 and this setting as system
> load dictates. To enable ACPI CPU idling control,
> machdep.cpu_idle_hlt must be set to 1.
>
> $ sysctl -d machdep.cpu_idle_hlt
> sysctl: unknown oid 'machdep.cpu_idle_hlt'
>
> I'm taking a stab in the dark here, but it looks like the variable no
> longer exists because it's been replaced with, effectively, the
> framework that drives machdep.idle and machdep.idle_available
> (specifically the mwait_hlt and hlt methods). Doing "grep -r
> cpu_idle_hlt /usr/src" turns up nothing other than the cpu_idle_hlt()
> functions that live within machdep.c per architecture, and those (based
> on the code) correlate with what's shown in machdep.idle_available.
>
> If I'm correct, I believe that means we can safely remove the last line
> of text in the acpi(4) man page?
>
> There's also a mention of this variable in a file called
> src/tools/tools/sysdoc/tunables.mdoc, but I'm not sure what that is.
Hmm, it appears that it is indeed deprecated.
--
John Baldwin
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