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The NULL TTY Driver Makes It Into The Linux 5.2 Kernel

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  • The NULL TTY Driver Makes It Into The Linux 5.2 Kernel

    Phoronix: The NULL TTY Driver Makes It Into The Linux 5.2 Kernel

    At first there was some concern over the practicality and use-cases for this driver, the NULL TTY driver has been merged for the Linux 5.2 kernel as part of the TTY/serial updates...

    http://www.phoronix.com/scan.php?pag...r-Lands-In-5.2

  • uxmkt
    replied
    Originally posted by DoMiNeLa10 View Post
    I think the cost of syscalls is pretty significant as well, especially nowadays. It really becomes an issue when you're CPU bound, which I assume to be the case when booting up.
    Don't assume - measure. Anyhow, replacing sh scripts by systemd units probably did its deed in regard to reducing system calls, "accidentally" even.

    Leave a comment:


  • DoMiNeLa10
    replied
    Originally posted by Zan Lynx View Post
    A big part of the slowdown is when the console is a graphics framebuffer. Instead of writing a byte per character it's now writing hundreds of bytes per character. And if it doesn't have hardware scroll support, it has to memmove the whole buffer for every newline.
    I think the cost of syscalls is pretty significant as well, especially nowadays. It really becomes an issue when you're CPU bound, which I assume to be the case when booting up.

    Leave a comment:


  • Zan Lynx
    replied
    A big part of the slowdown is when the console is a graphics framebuffer. Instead of writing a byte per character it's now writing hundreds of bytes per character. And if it doesn't have hardware scroll support, it has to memmove the whole buffer for every newline.

    Leave a comment:


  • DoMiNeLa10
    replied
    Originally posted by oleid View Post
    Uh, we desperately need a boot-up time benchmark using this and the default driver! 🤣
    You'd be surprised how much time you can lose trying to write to the console. Try comparing boot times with and without the "quiet" kernel parameter.
    Last edited by DoMiNeLa10; 05-12-2019, 09:12 AM.

    Leave a comment:


  • oleid
    replied
    Uh, we desperately need a boot-up time benchmark using this and the default driver! 🤣

    Leave a comment:

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