# Simple OpenCL kernel freezes system with Stream SDK 2.1

Discussion created by koarl0815 on Jun 17, 2010
Latest reply on Jun 18, 2010 by koarl0815

Hello,

The attached OpenCL kernel is supposed to compute a plane rotation of two vectors. For some reasons, it leads to a system freeze under Stream SDK 2.1, while it works correctly under another OpenCL implementation. Does anyone have an idea why this could be the case? Could it be related to a bug in the Stream SDK?

Again, the WARNING: The code below may freeze your system.

Best regards,
Karli

////// plane rotation: (x,y) <- (\alpha x + \beta y, -\beta x + \alpha y) __kernel void plane_rotation( __global float * vec1, __global float * vec2, float alpha, float beta, unsigned int size) { float tmp1 = 0; float tmp2 = 0; for (unsigned int i = get_global_id(0); i < size; i += get_global_size(0)) { tmp1 = vec1[i]; tmp2 = vec2[i]; //the following barrier is not needed, but does not improve the situation. barrier(CLK_GLOBAL_MEM_FENCE); vec1[i] = alpha * tmp1 + beta * tmp2; vec2[i] = alpha * tmp2 - beta * tmp1; } };