__syncthreads()死锁 [英] __syncthreads() Deadlock
问题描述
如果只有一些线程执行,__syncthreads()会导致死锁吗?
Will __syncthreads() cause a dead lock if only some threads execute it?
我有一个这样的内核:
__global__ void Kernel(int N,int *a)
{
if(threadIdx.x<N)
{
for(int i=0;i<N;i++)
{
a[threadIdx.x]= //Some calculation using a and i
__syncthreads()
}
}
}
如果块中的线程数大于N ,那么一些线程将不会执行代码。这将导致死锁吗?
如果是,那么我如何修改代码?
if the number of threads in the block is greater than N, then some threads will not execute the code. will this cause a deadlock?
if yes, then how can i modify the code?
推荐答案
应该不在分歧代码中使用 __ syncthreads()
。它在这种情况下的行为是未定义的。
You should not use __syncthreads()
in a divergent code. Its behaviour in such circumstances is undefined.
__ syncthreads()
,这个分支将以相同的方式由一个块中的所有线程(或者全部,或者一个块中没有线程取分支)统一计算。
__syncthreads()
may appear in a conditional branch only if you are sure, this branch will be evaluated uniformly, in the same way, by all threads in a block (either all, or no threads from a block take the branch).
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