3 ms·

Explain how to do locks without using the lock instruction!

• jnordwick 4y ago
  does xchg count
  • jart 4y ago
    That's an implicit lock.
• monocasa 4y ago
  futex will do lock instructions for you in kernel space. It's non optimal to just jump to kernel space every time, but it should still at least be correct.
  • jart 4y ago
    A system call has even more overhead than the lock prefix!
    • monocasa 4y ago
      True, but arguably this article constrains itself to the kernel-user boundary, where atomic instructions could be considered out of scope considering how the Linux syscall ABI is constructed.
      • jart 4y ago
        https://www.reddit.com/r/C_Programming/comments/120momf/a_lockfree_single_element_generic_queue/ https://www.reddit.com/r/C_Programming/comments/120momf/a_lo...