cpuspeed(8)

1CPUSPEED(8)                     Program Options                    CPUSPEED(8)
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NAME

6       cpuspeed - user-space cpu frequency scaling program, v1.2.1
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SYNOPSIS

9       cpuspeed [Options]
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DESCRIPTION

12       cpuspeed v1.2.1
13
14       This  program  monitors  the  system's  idle  percentage and reduces or
15       raises the CPUs' clock speeds  and  voltages  accordingly  to  minimize
16       power consumption when idle and maximize performance when needed.  This
17       is the default.
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19       The program may also optionally be configured to reduce the CPUs' clock
20       speeds  if  the temperature gets too high, NOT minimize their speeds if
21       the computer's AC adapter is disconnected or maximize their speeds when
22       the AC adapter is connected.
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24       By default this program will manage every CPU found in the system.
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26              Options:
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28       -d
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30              Tells the process to daemonize itself (run in background).
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32       -i <interval>
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34              Sets  the  interval  between  idle percentage tests and possible
35              speed changes in tenths of a second (default is 20).
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37       -p <fast up> <threshold>
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39       Sets the CPU idle percentage thresholds.
40              <fast up> is the idle
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42              percentage below which a CPU will be set to the highest possible
43              speed.   <threshold>  is the idle percentage above which a CPU's
44              speed will be decreased and below which a CPU's  speed  will  be
45              increased (defaults are 10 and 25).
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47       -m <minimum speed>
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49              Sets the minimum speed in KHz below which a CPU will not be set.
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51       -M <maximum speed>
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53              Sets the maximum speed in KHz above which a CPU will not be set.
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55       -t <temp file> <maxtemp>
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57              Sets the ACPI temperature file and the temperature at which CPUs
58              will be set to minimum speed.
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60       -T <interval>
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62              Sets the interval at which the temperature  will  be  polled  in
63              tenths   of a second (default is 10).  (Requires the '-t' option
64              above.)
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66       -a <AC file>
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68              Sets the ACPI AC adapter state file and tells the program to set
69              the  CPUs  to minimum speed when the AC adapter is disconnected.
70              (This is the default  but  is  changeable  by  the  '-D'  option
71              below).
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73       -A <interval>
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75              Sets  the  interval at which the AC adapter state will be polled
76              in tenths  of a second (default  is  50).   (Requires  the  '-a'
77              option above.)
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79       -C
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81              Run  at  maximum  speed when AC adapter is connected.  (Requires
82              the '-a' option above.)
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84       -D
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86              Do NOT force minimum speed  when  AC  adapter  is  disconnected.
87              (Requires the '-a' option above.)
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89       -r
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91              Restores previous speed on program exit.
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93       -s <CPU>
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95       Manage only a single CPU.
96              <CPU> specifies the number of the CPU
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98              to manage and is in the range 0 to (n-1) where 'n' is the number
99              of CPUs in the system.  Without this option the program  creates
100              copies of itself to manage every CPU in the system.
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102              To  have  a CPU stay at the highest clock speed to maximize per‐
103              formance send the process controlling that CPU the SIGUSR1  sig‐
104              nal.
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106              To have a CPU stay at the lowest clock speed to maximize battery
107              life send the process controlling that CPU the SIGUSR2 signal.
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109              To resume having a CPU's clock speed dynamically scaled send the
110              process controlling that CPU the SIGHUP signal.
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112   Notes:
113       Many  modern Linux systems support in-kernel cpu frequency scaling. The
114       cpuspeed daemon only works in conjunction  with  the  'userspace'  fre‐
115       quency  scaling governor. Other governors, such as 'ondemand' and 'con‐
116       servative', rely on the Linux kernel to adjust cpu frequencies  on  the
117       fly  without  the  need of any user-space assistance, such as that pro‐
118       vided by cpuspeed.
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120       Red Hat and Fedora distributions employ a  unified  configuration  file
121       for both scenarios, as well as a cpuspeed init script that will config‐
122       ure either cpuspeed or in-kernel cpu frequency scaling, as appropriate.
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FILES

125       /etc/sysconfig/cpuspeed, configuration file
126       /etc/init.d/cpuspeed, initialzation script
127       /usr/sbin/cpuspeed, cpuspeed program
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LICENSE

134       CPUSpeed is released under the GNU General Public License version 2 (or
135       if you wish any later version). This license allows you to use, copy,
136       distribute and modify the software with very few restrictions. The full
137       text of the license may be found here:
138         http://carlthompson.net/Software/CPUSpeed/License
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AUTHOR(S):

141       CPUSpeed daemon, original init script and configuration file:
142              Carl Thompson - cet [at] carlthompson.net
143                  (copyright 2002 - 2005)
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145       Modernized init script, configuration file and man page:
146              Dave Jones - davej [at] redhat.com
147              Michal Jaegermann - michal [at] harddata.com
148              Jarod Wilson - jwilson [at] redhat.com
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152cpuspeed v1.2.1                January 09, 2005                    CPUSPEED(8)

NAME

SYNOPSIS

DESCRIPTION

FILES

SEE ALSO

LICENSE

AUTHOR(S):