How to enable / disable Hyper-threading Technology dynamically by Linux
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Preface
Intel's hyper-threading technology allows two threads to be executed in parallel on a physical core, which in most cases can improve the utilization of hardware resources and enhance system performance. For cpu-intensive numerical programs, hyper-threading technology may lead to a decline in overall program performance. For this reason, it is recommended to turn off hyper-threading when executing OpenMP or MPI numeric programs.
Here are the scripts found on github to dynamically turn on and off hyper-threading technology. The principle is to find the relationship between the logical core according to the / sys/devices/system/cpu/cpuX/topology/thread_siblings_list file, and then edit the / sys/devices/system/cpu/cpuX/online file to dynamically open and close hyper-threading technology.
#! / bin/bashHYPERTHREADING=1function toggleHyperThreading () {for CPU in/ sys/devices/system/cpu/cpu [0-9] *; do CPUID= `basename $CPU | cut-b4-`basename $CPU | cut-b4-`basename en "CPU: $CPUID\ t" [- e $CPU/online] & & echo "1" > $CPU/online THREAD1= `cat $CPU/topology/thread_siblings_list | cut-F1-d, `if [$CPUID= $THREAD1] Then echo "- > enable" [- e $CPU/online] & & echo "1" > $CPU/online else if ["$HYPERTHREADING"-eq "0"]; then echo "- > disabled"; else echo "- > enabled" Fi echo "$HYPERTHREADING" > $CPU/online fi done} function enabled () {echo-en "Enabling HyperThreading\ n" HYPERTHREADING=1 toggleHyperThreading} function disabled () {echo-en "Disabling HyperThreading\ n" HYPERTHREADING=0 toggleHyperThreading} # ONLINE=$ (cat / sys/devices/system/cpu/online) OFFLINE=$ (cat / sys/devices/system/cpu/offline) echo "-- -"echo-en" CPU's online: $ONLINE\ t CPU's offline: $OFFLINE\ n "echo"-- "while true" Do read-p "Type in e to enable or d disable hyperThreading or q to quit [e/d/q]?" Ed case $ed in [Ee] *) enabled; break;; [Dd] *) disabled;exit;; [Qq] *) exit;; *) echo "Please answer e for enable or d for disable hyperThreading."; esacdone
Note:
Script needs root permission to execute
You can view the enabled cpu information through cat / proc/cpuinfo, which does not require root permission
The lscpu command can view the status of cpu (no root permission is required): the threads per core value is 2 in hyperthreaded state and 1. 0 when disabled.
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