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  • netplan导致systemd-networkd-wait-online.service卡住的问题

    如果用netplan控制网络设备,同时把设备设置成固定ip。如果对应的设备不存在,那么在系统启动后systemd-networkd-wait-online.service就会卡住几分钟,导致后续的服务无法执行。

    比如下面的网络设置

    network:
      version: 2
      ethernets:
        enx00e04c680c9b:
          dhcp4: false
          addresses:
            - 192.168.198.1/24
          routes:
            - to: default
              via: 192.168.198.1
              metric: 200
        enx344b50000000:
          dhcp4: true
          dhcp4-overrides:
            route-metric: 90
    

    这样即使enx00e04c680c9b这个网络设备不存在或者enx00e04c680c9b网口上没有插网线systemd-networkd-wait-online.service这个服务也还是会卡住。这是因为netplan默认的后台用的是systemd-network。按照这样设置之后系统图形界面中也是看不到被控制的网卡的。同时由于网络同时受两个后端控制,还可能导致dns错误等问题。

    我们可以让netplan也使用NetworkManager作为后端来解决这个问题。只需要在配置中增加 renderer: NetworkManager

    最后配置如下

    network:
      version: 2
      renderer: NetworkManager
      ethernets:
        enx00e04c680c9b:
          dhcp4: false
          addresses:
            - 192.168.198.1/24
          routes:
            - to: default
              via: 192.168.198.1
              metric: 200
        enx344b50000000:
          dhcp4: true
          dhcp4-overrides:
            route-metric: 90
    

    这样就不会存在卡住的问题。同时网卡也可以在系统网络设置界面中看到。

    posted in 技术交流
  • linux 优化启动速度

    https://wiki.archlinux.org/title/Improving_performance/Boot_process

    Improving the boot performance of a system can provide reduced boot wait times and serves as a means to learn more about how certain system files and scripts interact with one another. This article attempts to aggregate methods on how to improve the boot performance of an Arch Linux system.

    1 Analyzing the boot process

    1.1 Using systemd-analyze

    systemd provides a tool called systemd-analyze that can be used to show timing details about the boot process, including an svg plot showing units waiting for their dependencies. You can see which unit files are causing your boot process to slow down. You can then optimize your system accordingly.

    To see how much time was spent in kernelspace and userspace on boot, simply use:

    $ systemd-analyze
    

    Tip: If you boot via UEFI and use a boot loader which implements systemd’s Boot Loader Interface (which currently systemd-boot and GRUB do), systemd-analyze can additionally show you how much time was spent in the EFI firmware and the boot loader itself.

    To list the started unit files, sorted by the time each of them took to start up:

    $ systemd-analyze blame
    

    At some points of the boot process, things can not proceed until a given unit succeeds. To see which units find themselves at these critical points in the startup chain, do:

    $ systemd-analyze critical-chain
    

    You can also create an SVG file which describes your boot process graphically, similar to Bootchart:

    $ systemd-analyze plot > plot.svg
    

    See systemd-analyze(1) for details.

    1.2 Using bootchart2

    You could also use Bootchart2 to visualize the boot sequence.

    2 Using systemd instead of busybox on early init

    By default, the Mkinitcpio configuration uses the base and udev hooks for building the initramfs. Faster boot times can be achieved by replacing them with systemd.

    See Mkinitcpio#Common hooks for more details. See also Fsck#Boot time checking if replacing the fsck hook.

    3 Compiling a custom kernel

    Compiling a custom kernel can reduce boot time and memory usage. Though with the standardization of the 64-bit architecture and the modular nature of the Linux kernel, these benefits may not be as great as expected. See Kernel#Compilation for more info.

    4 Initramfs

    In a similar approach to #Compiling a custom kernel, the initramfs can be slimmed down. A simple way is to include the mkinitcpio autodetect hook. If you want to go further than that, see Minimal initramfs.

    Depending on your hardware (processor and storage speed), using lz4 instead of the default zstd compression option may be quicker since the faster decompression speed at boot time usually offsets the slightly larger size of the initramfs that has to be read from disk. See Mkinitcpio#COMPRESSION.

    5 Choose the adequate way to start for services

    One central feature of systemd is D-Bus and socket activation. This feature should be preferred for most cases as it causes services to be started only when they are first accessed and is generally a good thing (e.g. having cups.service enabled at boot time is usually not useful for desktop use, enable instead cups.socket which will only start the service when actually printing).

    However, if you know that a service (like upower) will always be started during boot, then the overall boot time might be reduced by starting it as early as possible. This can be achieved (if the service file is set up for it, which in most cases it is) by enabling upower.service.

    This will cause systemd to start UPower as soon as possible, without causing races with the socket or D-Bus activation.

    6 Staggered spin-up

    Some hardware implements staggered spin-up, which causes the OS to probe ATA interfaces serially, which can spin up the drives one-by-one and reduce the peak power usage. This slows down the boot speed, and on most consumer hardware provides no benefits at all since the drives will already spin-up immediately when the power is turned on. To check if SSS is being used:

    # dmesg | grep SSS
    

    If it was not used during boot, there will be no output.

    To disable it, add the libahci.ignore_sss=1 kernel parameter.

    7. Filesystem mounts

    Thanks to mkinitcpio’s fsck hook, you can avoid a possibly costly remount of the root partition by changing ro to rw on the kernel line: options can be set with rootflags=rw,other_mount_options. The entry must be removed from the /etc/fstab file, otherwise the systemd-remount-fs.service will continue to try applying these settings. Alternatively, one could try to mask that unit.

    If Btrfs is in use for the root filesystem, there is no need for a fsck on every boot like other filesystems. If this is the case, mkinitcpio’s fsck hook can be removed. You may also want to mask the systemd-fsck-root.service, or tell it not to fsck the root filesystem from the kernel command line using fsck.mode=skip. Without mkinitcpio’s fsck hook, systemd will still fsck any relevant filesystems with the systemd-fsck@.service

    You can also remove API filesystems from /etc/fstab, as systemd will mount them itself (see pacman -Ql systemd | grep ‘.mount$’ for a list). It is not uncommon for users to have a /tmp entry carried over from sysvinit, but you may have noticed from the command above that systemd already takes care of this. Ergo, it may be safely removed.

    Other filesystems, like /home or EFI system partition, can be mounted with custom mount units. Adding noauto,x-systemd.automount to mount options will buffer all access to that partition, and will fsck and mount it on first access, reducing the number of filesystems it must fsck/mount during the boot process.

    Note:

    This will make your /home filesystem type autofs, which is ignored by mlocate by default. The speedup of automounting /home may not be more than a second or two, depending on your system, so this trick may not be worth it.

    If the system is installed into a btrfs subvolume (specifically: the root directory / itself is a subvolume) and /home is a separate file system, you may also want to prevent the creation of a /home subvolume. Mask the home.conf tmpfile: ln -s /dev/null /etc/tmpfiles.d/home.conf.

    8. Less output during boot

    For some systems, particularly those with an SSD, the slow performance of the TTY is actually a bottleneck, and so less output means faster booting. See the Silent boot article for suggestions.

    9. Changing boot loader

    Changing your boot loader (e.g. a simpler boot loader such as systemd-boot) may reduce boot time by seconds.

    If your setup allows it, try using only EFISTUB for even shorter boot times.

    10. Suspend to RAM

    The best way to reduce boot time is not booting at all. Consider suspending your system to RAM instead.

    posted in 技术交流
  • RE: 底盘驱动问题

    @lyon https://community.bwbot.org/topic/16624/ubuntu中用udev规则绑定usb串口和映射别称的办法

    posted in 产品服务
  • RE: 底盘驱动问题

    @lyon 要自己添加udev规则创建底盘串口的符号连接 /dev/ttyUSB001

    posted in 产品服务
  • RE: solve raspbian SD card corruption issues with read-only mounted root partition

    @weijiz 注意在orangepi5中我们改了/sbin/init文件,这个是挂载的入口

    posted in 技术交流
  • RE: 自动充电测试xiaoqiang_local.launch失败

    @yao 还有你现在电压很高应该已经充满了。如果不是那就超出充电桩电压范围了。最高支持48V锂电池电压范围。

    posted in 技术交流
  • RE: 自动充电测试xiaoqiang_local.launch失败

    @yao 用检测工具时是否点击使能充电。还有一个可能是充电器如果是脉冲式充电,电流也可能会很小。可以在参数里面设置current_bias把电流偏置提高试试

    posted in 技术交流
  • RE: 自动充电测试xiaoqiang_local.launch失败

    @yao 你的摄像头tf又没了。没有摄像头tf机器人不能知道二维码相对于机器人的位置。搜索一下论坛很多人都有你这个问题。参考一下别人的设置

    posted in 技术交流
  • RE: 自动充电测试xiaoqiang_local.launch失败

    @yao tf树不能断开,先学习一下tf的基础知识

    posted in 技术交流
  • RE: 自动充电测试xiaoqiang_local.launch失败

    @yao 不正常,缺里程计

    posted in 技术交流