Altera_Forum
Honored Contributor
Honored ContributorDoes initiation interval of 1 means no need for unrollment?
I have one basic question. In case of Single-Thread mode kernels, if I have one single loop and I'll be able to achieve initiation interval of one, is it still beneficial to unroll the loop? My assumption is, when you have II=1, then at each clock cycles you can go one step forward and it can achieve something almost like the unrollment of for loops.
In order to verify this observation, I have created some synthetic kernels. The kernels schema are like below:#define LL 16384# define UL 128
__kernel void WGSXMAPIXLL16384OPS8ST( const __global float * restrict GIn,
__global float * restrict GOut,
const float M,
const float N,
const float P) {
int Mi = M;
float tempOutTotal = 0;
# pragma unroll UL
for (int lcdd =0; lcdd < LL; lcdd++) {
float tempOut = N + lcdd;
float temp1 = 1.0;
//float temp2 = 1.0;
//float temp3 = 1.0;
//float temp4 = 1.0;
float temp = 0.0;
temp1 += temp1 * tempOut;
temp1 += temp1 * tempOut;
... // Total number of FMA ops
temp1 += temp1 * tempOut;
GOut = temp1;
//tempOutTotal += tempOut;
}
}
