Copyright (c) 2011 Jukka Ruohonen <jruohonen (at] iki.fi>
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.Dd February 17, 2017 .Dt ODCM 4 x86 .Os .Sh NAME .Nm odcm .Nd On-demand Clock Modulation .Sh SYNOPSIS .Cd "odcm0 at cpu0" .Sh DESCRIPTION The .Nm driver provides support for changing the duty cycle of a .Tn CPU . This is sometimes known as .Dq on-demand clock modulation
q Tn ODCM . Refer to .Xr acpicpu 4 for additional details about .Tn ODCM .
p The following .Xr sysctl 8 variables are available with .Nm : l -tag -width "machdep.clockmod.available " -offset indent t Ic machdep.clockmod.target The target duty cycle of all .Tn CPUs . The values range from 7 (100 %) to 0 (approximately 13 %). t Ic machdep.clockmod.current The current duty cycle of .Tn CPUs . t Ic machdep.clockmod.available A list of available duty cycles. .El
p Note that some errata may limit the availability of some duty cycles. .Sh SEE ALSO .Xr acpicpu 4 , .Xr x86/est 4 , .Xr x86/powernow 4 .Sh CAVEATS .Tn ODCM is meant for short-term thermal management, not power management. There is usually no reason for a system administrator to change the values manually. Lowering the duty cycle may dramatically decrease performance and responsiveness of the system.
Indexes created Wed Sep 24 05:09:52 GMT 2025