The following is an example of a matrix multiplication with a
(64 * 64) x (64 * 64)
matrix size, and int8 x int8
data type. The matrix multiplication shape is 4*16*8
. The input data is reshaped for matrix multiplication.
const int SHIFT=10;
//For element mmul
const int M=4;
const int K=16;
const int N=8;
//Total matrix sizes
const int rowA=64;
const int colA=64;
const int colB=64;
//mmul numbers
const int num_rowA=rowA/M;
const int num_colA=colA/K;
const int num_colB=colB/N;
void matrix_mul(input_buffer<int8> & __restrict matA, input_buffer<int8> & __restrict matB, output_buffer<int8> & __restrict matC){
using MMUL = aie::mmul<M, K, N, int8, int8>;
const int8* __restrict pA=(int8*)matA.data();
const int8* __restrict pB=(int8*)matB.data();
int8* __restrict pC=(int8*)matC.data();
//For profiling only
unsigned cycle_num[2];
aie::tile tile=aie::tile::current();
cycle_num[0]=tile.cycles();//cycle counter of the AI Engine tile
for (unsigned i = 0; i < num_rowA; i++) { //for output row number of element matrix
for (unsigned j = 0; j < num_colB; j++) { //for output col number of element matrix
const int8 * __restrict pA1 = pA + ( i * num_colA + 0) * MMUL::size_A;
const int8 * __restrict pB1 = pB + ( 0 * num_colB + j) * MMUL::size_B;
aie::vector<int8, MMUL::size_A> A0 = aie::load_v<MMUL::size_A>(pA1); pA1 += MMUL::size_A;
aie::vector<int8, MMUL::size_B> B0 = aie::load_v<MMUL::size_B>(pB1); pB1 += MMUL::size_B * num_colB;
MMUL C00; C00.mul(A0, B0);
for (unsigned k = 0; k < num_colA-1; k++) {
A0 = aie::load_v<MMUL::size_A>(pA1); pA1 += MMUL::size_A;
B0 = aie::load_v<MMUL::size_B>(pB1); pB1 += MMUL::size_B * num_colB;
C00.mac(A0, B0);
}
aie::store_v(pC, C00.template to_vector<int8>(SHIFT)); pC += MMUL::size_C;
}
}
//For profiling only
cycle_num[1]=tile.cycles();//cycle counter of the AI Engine tile
printf("start=%d,end=%d,total=%d\n",cycle_num[0],cycle_num[1],cycle_num[1]-cycle_num[0]);
}
The profiled result shows that the loop takes around 3888 cycles. In total,
this is 64*64*64=262144 multiplications on int8*int8
data
type, which is 262144/3888 ~=67 int8*int8
MAC operations
per cycle.
Note that above result uses default settings foraiecompiler
, which will automatically do optimization like loop pipelining for
the loops.