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

CPUID=`basename $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

Disable / Enable HyperThreading cores on runtime – linux

原创文章，作者：kinpo, k，如若转载，请注明出处：https://www.yidc.net/archives/4597