Linux动态启用/禁用超线程技术

intel的超线程技术能让一个物理核上并行执行两个线程，大多数情况下能提高硬件资源的利用率，增强系统性能。对于cpu密集型的数值程序，超线程技术可能会导致整体程序性能下降。鉴于此，执行OpenMP或者MPI数值程序时建议关闭超线程技术。

以下是github上找到的动态打开、关闭超线程技术的脚本。其原理是根据/sys/devices/system/cpu/cpuX/topology/thread_siblings_list文件找到逻辑核的关系，然后编辑/sys/devices/system/cpu/cpuX/online文件实现动态开启和关闭超线程技术。

#!/bin/bash    HYPERTHREADING=1    function toggleHyperThreading() {    for CPU in /sys/devices/system/cpu/cpu[0-9]*; do        CPU cut -b4-`        echo -en "CPU: $CPUIDt"        [ -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" > $CPU/online        fi    done  }    function enabled() {          echo -en "Enabling HyperThreadingn"          HYPERTHREADING=1          toggleHyperThreading  }    function disabled() {          echo -en "Disabling HyperThreadingn"          HYPERTHREADING=0          toggleHyperThreading  }    #  ONLINE=$(cat /sys/devices/system/cpu/online)  OFFLINE=$(cat /sys/devices/system/cpu/offline)  echo "---------------------------------------------------"  echo -en "CPU's online: $ONLINEt CPU's offline: $OFFLINEn"  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.";;      esac  done  

备注：

1.脚本需root权限执行；
2.可以通过cat /proc/cpuinfo查看启用的cpu信息，该命令无需root权限；
3.lscpu命令可查看cpu的状态（无需root权限）：超线程状态下threads per core数值为2，禁用时为1.

参考

1. Disable / Enable HyperThreading cores on runtime – linux

原文出处：segmentfault -> https://segmentfault.com/a/1190000019687661