79 lines
2.4 KiB
Common Lisp
79 lines
2.4 KiB
Common Lisp
// Constants for kernels 1 -- 5
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#define TS 32 // The square-root of the 2D tile-size (== work-group dims)
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// Constants for kernels 3, 5
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#define WPT 8 // The amount of work-per-thread, i.e. the thread-coarsening factor
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#define RTS (TS/WPT) // The reduced tile-size in one dimension
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// Increased the amount of work-per-thread by a factor WPT
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__kernel void sgemm(const __global float* A,
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const __global float* B,
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__global float* C,
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const int M, const int N, const int K) {
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// Thread identifiers
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const int row = get_local_id(0); // Local row ID (max: TS)
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const int col = get_local_id(1); // Local col ID (max: TS/WPT == RTS)
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const int globalRow = TS*get_group_id(0) + row; // Row ID of C (0..M)
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const int globalCol = TS*get_group_id(1) + col; // Col ID of C (0..N)
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// Local memory to fit a tile of TS*TS elements of A and B
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__local float Asub[TS][TS];
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__local float Bsub[TS][TS];
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// Initialise the accumulation registers
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float c_temp[WPT];
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for (int w=0; w<WPT; w++) {
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c_temp[w] = 0.0f;
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}
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// Loop over all tiles
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const int nTiles = (K + TS - 1) / TS;
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for (int t=0; t<nTiles; t++) {
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// Load one tile of A and B into local memory
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for (int w=0; w<WPT; w++) {
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const int tiledRow = TS*t + row;
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const int tiledCol = TS*t + col;
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if(globalRow + w*RTS < M && tiledCol < K)
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{
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Asub[row + w*RTS][col] = A[(globalRow + w*RTS)*K + tiledCol];
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}
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else
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{
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Asub[row + w*RTS][col] = 0.0f;
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}
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if(globalCol < N && tiledRow + w*RTS < K)
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{
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Bsub[row + w*RTS][col] = B[(tiledRow + w*RTS)*N + globalCol];
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}
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else
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{
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Bsub[row + w*RTS][col] = 0.0f;
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}
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}
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// Synchronise to make sure the tile is loaded
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barrier(CLK_LOCAL_MEM_FENCE);
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// Perform the computation for a single tile
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for (int k=0; k<TS; k++) {
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for (int w=0; w<WPT; w++) {
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c_temp[w] += Asub[row + w*RTS][k] * Bsub[k][col];
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}
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}
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// Synchronise before loading the next tile
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barrier(CLK_LOCAL_MEM_FENCE);
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}
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// Store the final results in C
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for (int w=0; w<WPT; w++) {
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if(globalRow + w*RTS < M && globalCol < N)
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{
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C[(globalRow + w*RTS)*N + globalCol] = c_temp[w];
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}
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}
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}
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