Transmeta(tm) crusoe(tm) longrun(tm) utility
longrun [-c device] [-m device] [-hlpv] [-f flag] [-s low high] [-t num]
The longrun utility is used to control and query LongRun settings on Transmeta Crusoe processors.
-c device
Set the CPUID device. The default CPUID device is /dev/cpu/0/cpuid.
-m device
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 CPU.
The following values are reported on all Transmeta CPUs that implement LongRun.
%
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 level.
-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.
-f flag
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 and writable.
Daniel Quinlan <[email protected]>