Is there any simple way to improve performance of this spinlock function?

问题

I'm trying to implement a spinlock in my code but the spinlock that I implemented based on Wikipedia results in extremely slow performance.

int lockValue = 0;

void lock() {
    __asm__("loop: \n\t"
            "movl $1, %eax \n\t"
            "xchg %eax, lockValue \n\t"
            "test %eax, %eax \n\t"
            "jnz loop");
}

Is there any way of improving this to make it faster?

Thanks.

回答1:

How about something like this (I understand this is the KeAcquireSpinLock implementation). My at&t assembly is weak unfortunately.

spin_lock:
    rep; nop
    test lockValue, 1
    jnz spin_lock
    lock bts lockValue
    jc spin_lock

回答2:

  "movl    $1,%%edx     \n\t"    // edx = 1;
  ".set    lockloop,.   \n\t"    // symbol lockloop set to pc
  "xorl    %%eax,%%eax  \n\t"    // eax = 0;
  "lock cmpxchgl %%edx,(%%ebx)\n\t" // if (*mu_ptr == eax) *mu_ptr = edx;
                                 //    else { eax = *mu_ptr;
  "jnz     lockloop     \n\t"    //           goto lockloop; }

来源：https://stackoverflow.com/questions/11923151/is-there-any-simple-way-to-improve-performance-of-this-spinlock-function