1
我偶然碰到排队的自旋锁，并想用C++实现。我搜索了一下这方面的信息，但无法获得正确的文档。排队的自旋锁
任何文档/实施技巧将不胜感激。
在此先感谢
我的代码如下疑问迈克尔·布朗
// represents processor in wait queue of the spinlock
struct qsl_entry
{
// next processor in the queue that is waiting to enter section
qsl_entry* next;
// indicates whether the access to section has been granted to processor
int state;
};
// queued spinlock
struct qsl
{
// the first processor in the queue that is waiting to enter section
qsl_entry* head;
};
// requests access to critical section guarded by the spinlock,
// if the section is already taken it puts processor to wait
// and insert it into queue
// lck - queued lock that used to guard section
// ent - entry that represent processor in queue of the spinlock
void lock_qsl(qsl* lck, qsl_entry* ent)
{
__asm
{
mov eax, ent;
mov ebx, lck;
// prepare queue entry
mov [eax], 0;
mov edx, eax;
mov [eax]qsl_entry.state, 1;
// store it as the last entry of the queue -- Is this what is line is doing ?
// ebx contains address of lck & [ ebx ] refers to address pointed by lck &
// it is over written to ent. eax now contains the memory the lck was pointing to.
lock xchg [ebx],eax;
// if the section available grant access to processor?
test eax, eax;
jz enter_section;
// link new entry with the rest of queue -- really ? are we nt overwritting
// the next pointer here ?
mov [eax],edx
// wait for processor's turn
wait1:
pause;
cmp [edx]qsl_entry.state, 1;
je wait1;
enter_section:
}
}
指出这是实现甚至正确吗？我很怀疑！
http://www.codeproject.com/Tips/100195/Queued-spinlocks似乎是一个合适的实现 –
感谢您的链接，但我已经发现它在我的谷歌搜索。我应该在我的问题中加上这个。问题是它似乎没有太多的文档与它相关联。对于像这样的复杂话题，一些直觉会很好。 – KodeWarrior
啊是的，即时通讯不好意思，你的问题确实说明你想要的细节。你以后有什么细节？ 排队的螺旋锁是旋转锁的链接列表，每个进入关键部分的线程都有一个锁。文章指出，当多个处理器只使用一个自旋锁时，这有助于缓存和缓存内存问题。 –