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Reference igmp  通过组播，可以实现一个主机同时向组内的多台主机发送数据，节省网络带宽。 组播ip地址范围是224.0.0.0-----239.255.255.255，其中224.0.0.0-----224.0.0.255是有特殊用途的保留地址，239.0.0.0-----239.255.255.255是私网地址，224.0.1.0-----238.255.255.255是用于公网上的组播地址。 组播有一系列的协议支持包括： 1、用于主机和路由器之间的IGMP协议。实现主机加入、离开组播组等功能。 2、路由器之间的组播协议有：PIM-SM、PIM-DM。实现嫁接、剪枝等功能。 还有一个IGMP Snooping，用在交换机上。开启IGMP Snoop...

Reference send patch to linux upstream # install git and setup git yum install git yum install git-email git config --global user.name "xxx" git config --global user.email "xxx@xxx.com" # 配置 ~/.gitcommit文件 selftests: bonding: add tests for ether type changes Why I do these changes and how I do it. Signed-off-by: Liang Li <liali@redhat...

Reference CONCEPTS systemd is a system and service manager for Linux operating systems. When run as first process on boot (as PID 1), it acts as init system that brings up and maintains userspace services. CONCEPTS systemd provides a dependency system between various entities called "units" of 11 different types. Units encapsulate vari...

Reference Compile Kernel # compile kernel CONFIG_DEBUG_INFO_BTF=n CONFIG_SYSTEM_TRUSTED_KEYS="" dnf install -y ncurses-devel openssl openssl-devel elfutils-libelf-devel flex bison bc dwarves tar make menuconfig make -j8 all make modules_install make install brew # brew bash /mnt/tests/kernel/networking/common/tools/brewkoji_install.sh brew d...

Reference NIC Offloads NIC tso and bond tso can take effect respectively But if bond tso is off, NIC tso can't take effect. Bond doesnt propagate conf to slaves. Didn't see GSO take effect on NIC and bond. GSO is a software implementation of tso. Bond doesnt propagate conf to slaves. NIC gro can take effect. But no difference when bond GRO i...

Reference Limit process cpu usage using cgroup limit_cpu_usage() { local pid=$1 if mount -l | grep -q cgroup2;then local cgroup_dir=$(mount -l | grep cgroup2 | awk '{print $3}' | head -n1) # Configure the system to mount cgroups-v2 by default during system boot by the systemd system and service manager: # grubby --update-kernel=/boot...

man page sched 每个线程对应一种调度策略和一个静态优先级 对于SCHED_OTHER, SCHED_IDLE, SCHED_BATCH调度策略的线程，静态优先级固定为0 对于SCHED_FIFO, SCHED_RR调度策略的线程，静态优先级可设置范围是1-99 对于每一个静态优先级，系统维护一个拥有此优先级的可执行线程列表 调度的时候，按照静态优先级从大到小的顺序，从队列中取线程进行调度。 因此，拥有SCHED_FIFO, SCHED_RR调度策略的线程总是会比SCHED_OTHER, SCHED_IDLE, SCHED_BATCH调度策略的线程优先， 并且会抢占（当SCHED_FIFO, SCHED_RR调度策略的线程需要调度时，会抢占SCHED_OTHER, S...

redhat doc install SNO Install SNO https://docs.google.com/document/d/1UZAAlbTU7g97vqkWhsfL2i3LpOaPhmMSus3oi6m-cXI/edit# OpenShift Container Platform on a single node is a specialized installation that requires the creation of a special ignition configuration ISO. The primary use case is for edge computing workloads, including intermittent c...