Kernel

How upgrade kernel

    #!/bin/bash

    #1.select the kernel will use
    eselect kernel list
    eselect kernel set <No.>
    #2.configure the kernel with old config (and diff with previous config)
    zcat /proc/config.gz > /usr/src/linux/.config
    diff .config ../linux-x.xx.x-gentoo/.config
    make silentoldconfig/syncconfig/oldconfig
    #3.compile&install kernel/modules
    make -j9
    make install
    # compile&install out-of-tree module(s)
    make modules_prepare
    emerge --ask @module-rebuild
    # install initramfs
    genkernel --install initramfs
    #4.clean up old kernel files
    eclean-kernel
    grub-mkconfig -o /boot/grub/grub.cfg

Configure kernel

将 intel wifi 固件编译进内核

Enable CONFIG_IWLWIFI and CONFIG_IWLMVM
固件与网卡之间的对应关系可参考iwlwifi驱动的wiki文档
将在上面找到的与网卡对应的的二进制固件名称填入 EXTRA_FIRMWARE 选项中。此选项的值是一个空格分隔的固件文件名字符串，这些文件必须位于 CONFIG_EXTRA_FIRMWARE_DIR 目录中(其默认值为 /lib/firmware ).

    Symbol: EXTRA_FIRMWARE
    Type  : string
    Prompt: Build named firmware blobs into the kernel binary
      Location:
        -> Device Drivers
          -> Generic Driver Options
            -> Firmware loader
              -> Firmware loading facility (FW_LOADER [=y])

将 Intel microcode 编译进内核

Enable CONFIG_MICROCODE, and CONFIG_MICROCODE_INTEL

    Processor type and features  --->
        <*> CPU microcode loading support
        [*]   Intel microcode loading support

查找 CPU 和 microcode 的对应关系

    #查看microcode的sig值:
    dmesg | grep microcode
    #例如sig=0x306c3

    #然后查看intel-ucode目录:
    ls /lib/firmware/intel-ucode
    #在目录中找到与sig值对应为06-3c-03的microcode

将在上面找到 microcode 名称填入 EXTRA_FIRMWARE 选项中

其他配置

开启 zswap

在内核中选中 zswap 对应的选项后，在=CONFIG_CMDLINE=中添加对应选项开启：

CONFIG_CMDLINE="zswap.enabled=1 zswap.compressor=lz4 zswap.max_pool_percent=20 zswap.zpool=z3fold"

CPU Frequency scaling

CONFIG_CPU_FREQ_GOV_POWERSAVE 配合 CONFIG_X86_INTEL_PSTATE 使用，效果与 CONFIG_CPU_FREQ_GOV_ONDEMAND 差异不大。甚至可以获得比 CONFIG_CPU_FREQ_GOV_ONDEMAND 更优秀的"性能/瓦特"比。

I/O Schedulers

TODO

创建 udev 使得 lightdm 反复重启，最终导致退出

https://blog.justforlxz.com/2019/10/24/%E7%BB%99Archlinux%E5%BC%80%E5%90%AFBFQ%E5%92%8CMuQSS/