Host Setting：
1、关闭power savings mode在BIOS中
2、设置 /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor 为 performance
3、添加启动参数GRUB_CMDLINE_LINUX="intel_iommu=on isolcpus=1-13 nohz_full=1-13 rcu_nocbs=1-13 hugepagesz=1GB hugepages=64 default_hugepagesz=1GB"
Guest setting run in KVM VM
1、关闭Irqbalance 服务
Irqbalance 服务缺省是开启的，它用于平衡irq在多核系统的各个CPU之间，然而它会导致运行vpp 的cpu停滞 进而导致Rx丢包，当Irqbalance服务关闭后，所有的irq都会备cpu0处理，因此不要运行vpp在cpu0上
2、echo 0 > /sys/kernel/mm/ksm/run
3、In order to run VPP in a VM, the following parameters must be configured on the command line invocation or in the libvirt / virsh xml domain configuration:-cpu host : This parameter causes the VM to inherit the host OS flags. (-cpu host & -m 8192 &-smp 2,sockets=1,cores=4,threads=2)
8 GB of ram is required for optimal zero packet drop rates. TBD: Need to investigate why this is true. 4GB has Rx pkt drops even though there is only 2.2GB allocated!
4、To disable PXE boot delays, add the ",rombar=0" option to the end of each "-device" option list or add "<rom bar=‘off‘/> to the device xml configuration.
5、<memballoon model=‘none‘/>
6、Set CPU Affinity and NUMA Memory Policy for the VPP VM threads
<cputune>
<vcpupin vcpu="0" cpuset="1/>
<vcpupin vcpu="1" cpuset="0,1"/>
<vcpupin vcpu="2" cpuset="2,3"/>
<vcpupin vcpu="3" cpuset="0,4"/>
<
utune>
<numatune>
<memory mode=‘strict‘ nodeset=‘0,2-3‘/>
</numatune>
7、echo never > /sys/kernel/mm/transparent_hugepages/enabled
8、Recommend turning this function off when running a single vpp instance.
echo 0 > /sys/kernel/mm/ksm/run
If it‘s not practical to turn off ksm, we recommend turning off ksm across numa nodes:
echo 0 > /sys/kernel/mm/ksm/merge_across_nodes