---
title: openEuler核隔离配置
description: "在HPC场景下，由于每个线程会频繁进行同步，OS背景噪声对性能的影响会随着节点数增多逐步放大，OS背景噪声包括背景守护进程、外设中断、内核背景线程等。"
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sourcePath: /source/zh/kunpenghpcs/KunpengDeveloper/usermanual/topic_0000002566375875.html
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---
# openEuler核隔离配置

#### openEuler核隔离介绍

在HPC场景下，由于每个线程会频繁进行同步，OS背景噪声对性能的影响会随着节点数增多逐步放大，OS背景噪声包括背景守护进程、外设中断、内核背景线程等。

增强核隔离特性将系统CPU分为housekeeping CPU和non-housekeeping CPU，将OS背景噪声集中在housekeeping CPU上，non-housekeeping CPU只运行业务计算任务，通过减少业务运行时背景噪声的干扰，提升业务性能。non-housekeeping CPU可以通过启动参数nohz_full和isolcpus指定，增加enhanced_isolcpus参数后可以进一步消除磁盘IO的噪声干扰。


#### 核隔离配置步骤

1. 修改grub启动项。
  vim /boot/efi/EFI/openEuler/grub.cfg

  找到关键字“/vmlinuz”所在行，在行末尾添加以下内容：

```
irqaffinity=37,75,113,151,189,227,265,303,341,379,417,455,493,531,569,607 nohz_full=0-36,38-74,76-112,114-150,152-188,190-226,228-264,266-302,304-340,342-378,380-416,418-454,456-492,494-530,532-568,570-606 isolcpus=nohz,domain,managed_irq,0-36,38-74,76-112,114-150,152-188,190-226,228-264,266-302,304-340,342-378,380-416,418-454,456-492,494-530,532-568,570-606 rcu_nocbs=0-36,38-74,76-112,114-150,152-188,190-226,228-264,266-302,304-340,342-378,380-416,418-454,456-492,494-530,532-568,570-606
disable_sdei_nmi_watchdog enhanced_isolcpus
```


  当前鲲鹏920专业版上每个节点共2个CPU，每个CPU 8个NUMA，每个NUMA 38核，整机共608核，核隔离参数推荐将每个NUMA的最后1个核配置为housekeeping CPU，housekeeping CPU的优先级为“irqaffinity”，使内核进程/中断优先调度到housekeeping CPU上，减少系统对non-housekeeping CPU的影响。

  同时，因配置核隔离后，若程序使用MPI顺序绑核会导致部分计算进程在housekeeping CPU上运行，影响程序整体性能。在该配置下，MPI可以指定rankfile，显式指定进程绑定的核。

2. 重启节点，使核隔离参数生效。
3. 重启后执行 cat /proc/cmdline，确认参数是否添加成功。
4. 执行初始化脚本，将系统中断/服务绑定到housekeeping CPU，并进行性能配置。

```
#!/bin/bash
# 禁用自动优化Linux系统硬件中断CPU分配的服务，强制绑定到housekeeping CPU
systemctl stop irqbalance && systemctl mask irqbalance
#设置实时任务可以使用全部CPU时间
echo -1 > /proc/sys/kernel/sched_rt_runtime_us
#设置khugepaged 后台线程在合并页面时的碎片整理行为为不整理碎片
echo 0 >  /sys/kernel/mm/transparent_hugepage/khugepaged/defrag
#设置进程分配内存时的即时行为为从不整理碎片
echo never > /sys/kernel/mm/transparent_hugepage/defrag
#设置透明大页内存分配策略为系统全局开启
echo always > /sys/kernel/mm/transparent_hugepage/enabled
#禁用自动NUMA平衡
echo 0 > /proc/sys/kernel/numa_balancing
ps -aux | grep rcu_sched | grep -v 'grep' | awk  '{print $2}' >
~
/.tmp
cat
~
/.tmp | while read line; do taskset -pc 37,75,113,151,189,227,265,303,341,379,417,455,493,531,569,607 $line; done
ps -aux | grep kswapd | grep -v 'grep' | awk  '{print $2}' >
~
/.tmp
cat
~
/.tmp | while read line; do taskset -pc 37,75,113,151,189,227,265,303,341,379,417,455,493,531,569,607 $line; done
ps -aux | grep kcompactd  | grep -v 'grep' | awk  '{print $2}' >
~
/.tmp
cat
~
/.tmp | while read line; do taskset -pc 37,75,113,151,189,227,265,303,341,379,417,455,493,531,569,607 $line; done
ps -aux | grep rcuog | grep -v 'grep' | awk  '{print $2}' >
~
/.tmp
cat
~
/.tmp | while read line; do taskset -pc 37,75,113,151,189,227,265,303,341,379,417,455,493,531,569,607 $line; done
ps -aux | grep rcuos | grep -v 'grep' | awk  '{print $2}' >
~
/.tmp
cat
~
/.tmp | while read line; do taskset -pc 37,75,113,151,189,227,265,303,341,379,417,455,493,531,569,607 $line; done
# 配置所有核的模式为performance
for core_id in 0-607
do
echo performance > /sys/devices/system/cpu/cpufreq/policy${core_id}/scaling_governor
done
```