longrun - Transmeta(TM) Crusoe(TM) LongRun(TM) utility
longrun [-c device] [-m device] [-hlpv] [-f flag] [-s low high] [-t
The longrun utility is used to control and query LongRun settings on
Transmeta Crusoe processors.
Set the CPUID device. The default CPUID device is
Set the MSR device. The default MSR device is /dev/cpu/0/msr.
-h Print help.
-l List LongRun information about available performance levels for
The following values are reported on all Transmeta CPUs that
% An available performance level, expressed as a
percentage of range of available core CPU frequencies.
0 corresponds to the lowest available frequency and
100 corresponds to the highest.
MHz The core CPU frequency at that level.
Volts The core CPU voltage at that level.
usage The power usage relative to the maximum performance
-p Print current LongRun settings and status: whether LongRun is
enabled, whether LongRun Thermal Extensions are active, the
current LongRun performance window (expressed as a percentile
range), the current LongRun performance level (expressed as a
percentile), and the current LongRun flags.
-v Be more verbose.
Set a LongRun mode flag. Currently, the two supported flags are
performance and economy. This controls whether the processor is
in "performance mode" or "economy mode".
-s low high
Set the current LongRun performance window as a percentile
range. The low number cannot be greater than the high number.
The minimum and maximum performance values accepted by the CPU
are 0 and 100, respectively.
-t num Set current LongRun Thermal Extensions setting (0 to 8, 8 =
off). Take care with -t 0 and -t 1.
Longrun Thermal Extensions (LTX) is an alternative way to
manipulate the power saving functionality of the processor, by
controlling heat dissipation directly. Settings 2 through 8
represent power utilization levels from 25% to 100%,
respectively, in 12.5% increments. NOTE: Settings 0 and 1 are
listed as ’reserved’ in the TM5600 literature. Though they
appear to represent 0% and 12.5% respectively on the TM5800
chip, use these settings at your own risk.
Interaction with the -s flag: Originally intended as a mechanism
to use Transmeta chips on fanless machines (referred to
apocryphally as "coolrun"), the -t flag limits the power range
of the processor. The performance range of the processor is
limited first by the -t flag, and then subsequently the -s flag.
In other words, setting both ’-s 57 100’ and ’-t 6’ will result
in the processor running in the 57 to 75% power range.
Notes: This functionality may or may not provide you with
different performance per watt characteristings than the -s
flag. It is provided for completeness, and left as an exercise
to the reader to decide if it is appropriate on their system.
As mentioned above, use the -t 0 and -t 1 settings with caution.
No environment variables are used.
This program requires that the Linux CPUID and MSR devices be compiled
into the kernel (or loaded as kernel modules), that the CPUID character
device be readable, and that the MSR character device be both readable
acpid(8), apmd(8), hdparm(8)
Daniel Quinlan <email@example.com>
February 14, 2001