3 ms·

Thanks for your reply. This subject is still new to me. My understanding of that syntax is that it is a compiler memory barrier, not a CPU memory barrier becau

• loeg 3y ago
  Hey, no problem. > My understanding of that syntax is that it is a compiler memory barrier, not a CPU memory barrier because the asm block is empty (no sfence or mfence). In C11, you can write compiler-only fences with atomic_signal_fence: https://en.cppreference.com/w/c/atomic/atomic_signal_fence https://en.cppreference.com/w/c/atomic/atomic_signal_fence (In practice, though, I think it is rare that you actually want a compiler-only fence. Instead, correct use of acquire/release operations prevents reorderings.)
  • samsquire 3y ago
    Thank you loeg, I appreciate you and information you brought that TIL. I've been using a compiler fence to force reloads from memory to prevent -O3 from optimising away my variables/structs changing by other threads and keeping data in registers rather than reloading from memory each time. I saw the volatile recommended against from the Linux kernel programmers. such as my thread->running == 1 in my event loops for my threads. https://www.kernel.org/doc/html/latest/process/volatile-considered-harmful.html https://www.kernel.org/doc/html/latest/process/volatile-cons...
    • loeg 3y ago
      > I've been using a compiler fence to force reloads from memory to prevent -O3 from optimising away my variables/structs changing by other threads I would highly recommend using the language standard atomic primitives instead.