1 #!/bin/bash 2 # Copyright 2014 the V8 project authors. All rights reserved. 3 # Use of this source code is governed by a BSD-style license that can be 4 # found in the LICENSE file. 5 6 CPUPATH=/sys/devices/system/cpu 7 8 MAXID=$(cat $CPUPATH/present | awk -F- '{print $NF}') 9 10 set_governor() { 11 echo "Setting CPU frequency governor to \"$1\"" 12 for (( i=0; i<=$MAXID; i++ )); do 13 echo "$1" > $CPUPATH/cpu$i/cpufreq/scaling_governor 14 done 15 } 16 17 enable_cores() { 18 # $1: How many cores to enable. 19 for (( i=1; i<=$MAXID; i++ )); do 20 if [ "$i" -lt "$1" ]; then 21 echo 1 > $CPUPATH/cpu$i/online 22 else 23 echo 0 > $CPUPATH/cpu$i/online 24 fi 25 done 26 } 27 28 dual_core() { 29 echo "Switching to dual-core mode" 30 enable_cores 2 31 } 32 33 single_core() { 34 echo "Switching to single-core mode" 35 enable_cores 1 36 } 37 38 39 all_cores() { 40 echo "Reactivating all CPU cores" 41 enable_cores $((MAXID+1)) 42 } 43 44 45 limit_cores() { 46 # $1: How many cores to enable. 47 echo "Limiting to $1 cores" 48 enable_cores $1 49 } 50 51 case "$1" in 52 fast | performance) 53 set_governor "performance" 54 ;; 55 slow | powersave) 56 set_governor "powersave" 57 ;; 58 default | ondemand) 59 set_governor "ondemand" 60 ;; 61 dualcore | dual) 62 dual_core 63 ;; 64 singlecore | single) 65 single_core 66 ;; 67 allcores | all) 68 all_cores 69 ;; 70 limit_cores) 71 if [ $# -ne 2 ]; then 72 echo "Usage $0 limit_cores <num>" 73 exit 1 74 fi 75 limit_cores $2 76 ;; 77 *) 78 echo "Usage: $0 fast|slow|default|singlecore|dualcore|all|limit_cores" 79 exit 1 80 ;; 81 esac 82
