How To Change The CPU Frequency?

Installation

sudo apt-get install cpufrequtils

Running

Save the below in a set_freq.sh file

sudo cpufreq-set -c0 -g userspace
sudo cpufreq-set -c1 -g userspace
sudo cpufreq-set -c2 -g userspace
sudo cpufreq-set -c3 -g userspace

sudo cpufreq-set -c0 -f $1GHz
sudo cpufreq-set -c1 -f $1GHz
sudo cpufreq-set -c2 -f $1GHz
sudo cpufreq-set -c3 -f $1GHz


cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
cat /sys/devices/system/cpu/cpu1/cpufreq/scaling_cur_freq
cat /sys/devices/system/cpu/cpu2/cpufreq/scaling_cur_freq
cat /sys/devices/system/cpu/cpu3/cpufreq/scaling_cur_freq

Now execute

chmod +x set_freq.sh

To change the frequncy exeucute the below command

./set_freq.sh 2.2

The available freqencies can be found by

more cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

Running Benchmarks

We used Lulesh benchmark and Graph 500 for studying the change in temperature and execution time with change in frequency

Results

Frequency Temp Core 1 ℃ Temp Core ℃ Execution Time in Seconds
1197000 35 37 79.65
2261000 39 43 40.34
2394000 39 43 39.49
2527000 41 44 37.05
2660000 43 45 35.52
2793000 43 45 34.26
2926000 43 46 33.70
3059000 44 47 32.27
3192000 45 48 30.74
3193000 45 50 31.15

Frequency vs Tempararture Graph

Temparature-Frequency

Frequency vs Time Graph

Time-Frequency

Temparature reading in HPC Computer

Silp Temparature Reading

How to read CPU voltage for 64 bit computer

 sudo apt-get install msr-tools
 sudo modprobe msr
 sudo rdmsr 408 --bitfield 47:32 --decimal --processor 0

The value of register 408(x198) can be used to calculate the value of voltage. The value obtained from 32:47 bits on multiplying with (1 / 2^^13) gives the voltage.

Comparison of Frequency Vs Voltage

Max Frequency Max Voltage Min Voltage
1.2 GHz 0.86890 Volt 0.70386 Volt
1.4 GHz 0.86890 Volt 0.71838 Volt
1.6 GHz 0.86890 Volt 0.73291 Volt
1.8 GHz 0.86890 Volt 0.75232 Volt
2.0 GHz 0.87366 Volt 0.81055 Volt
2.2 GHz 0.87366 Volt 0.80579 Volt
2.4 GHz 0.90771 Volt 0.86890 Volt

Graph

Freq vs Voltage

Time for Various Programs

Program Userspace Time Ondemand Time
Compress 10gb file 01:55 Min 01:20 Min
Lulesh2.0 48.41 Sec 42.99 Sec
Convert File To Pdf - LibreOffice 6.41 Sec 4.30 Sec
Copy 1 GB 16.128 Sec 17.356 Sec

Comparison of Governors

The source code of Tebalo can be foun at https://github.com/CPUhackers/tebalo

Time

Program Ondemand Conservative Powersave Performance Rounder @ 1 Rounder @ 2 Rounder @ 5
Lulesh @ 30 29.76 31.35 74.26 30.89 43.21 41.91 43.46
Lulesh @ 35 56.16 56.80 132.25 57.02 79.10 82.87 77.30
Lulesh @ 40 97.24 96.40 215.02 95.29 136.79 128.67 132.02
Lulesh @ 45 159.65 175.90 359.83 157.57 217.00 225.11 209.52
Program Ondemand Tebalo
Graph 0.3k 0.3k 18.52 20.24
Graph 0.5k 0.5k 27.45 28.42
Graph 0.7k 0.7k 48.52 52.24
Graph 1k 1k 84.33 88.41

Max Temparatue

Program Ondemand Conservative Powersave Performance Rounder @ 1 Rounder @ 2 Rounder @ 5
Lulesh @ 30 58,57 56,55 44,43 56,55 55,53 56,55 55,53
Lulesh @ 35 58,56 58,56 45,44 57,56 56,55 56,55 55,53
Lulesh @ 40 60,58 60,59 45,44 59,57 57,56 58,56 57,54
Lulesh @ 45 59, 57 60,57 44,42 63,57 57,55 57,55 58,56

Min Temparatue

Program Ondemand Conservative Powersave Performance Rounder @ 1 Rounder @ 2 Rounder @ 5
Lulesh @ 30 44,43 39,40 40,40 42,42 41, 41 41,39 39,38
Lulesh @ 35 41,40 39,39 39,39 44,42 39, 39 40,39 41,39
Lulesh @ 40 41,41 41,40 39,39 47,45 40, 40 41,40 42,40
Lulesh @ 45 37, 36 39,37 38,37 43,40 42, 40 40,39 41,39

Average Temparature

Program Ondemand Conservative Powersave Performance Rounder @ 1 Rounder @ 2 Rounder @ 5
Lulesh @ 30 56.63,55.35 54.11, 52.81 42.53, 41.92 53.53,52.67 49.68, 48.22 49.22,47.97 49.03,46.55
Lulesh @ 35 55.32,53.96 55.01, 53.62 43.46,42.32 55.37,53.79 49.57, 48.52 50.04,48.94 48.36,46.01
Lulesh @ 40 57.01,55.38 57.09, 55.80 43.71,42.67 56.63,55.08 50.79, 49.79 51.21,50.01 50.05,47.76
Lulesh @ 45 55.51,52.91 56.34, 53.82 43.08, 40.57 56.72,53.75 50.65, 48.16 50.99,48.60 50.68,48.57