Lecture 2 â Threads - many-core.group

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GPU strategy 2 – kernel (part 2) // only compute if (a) thread is within the whole domain if (i > 0 && i < ni-1 && j > 0 && j < nj-1) { // and (b) thread is not on boundary of a block if ((threadIdx.x > 0) && (threadIdx.x < NI_TILE-1) && (threadIdx.y > 0) && (threadIdx.y < NJ_TILE-1)) { //evaluate derivatives d2tdx2 = (temp[ti+1][tj] - 2*temp[ti][tj] + temp[ti-1][tj]); d2tdy2 = (temp[ti][tj+1] - 2*temp[ti][tj] + temp[ti][tj-1]); // update temperature temp_out[i2d] = temp_in[i2d] + tfac*(d2tdx2 + d2tdy2); } }
Performance • CPU – 1 <strong>core</strong>, Intel Xeon 2.33 GHz 1.83 E-8 s/point/step • GPU v1 (no shared mem) – GTX280 • GPU v2 (shared mem - 1) – GTX280 2.32 E-10 (80x speedup) 3.34 E-10 (55x speedup)
Page 1 and 2: Lecture 2 - Threads Graham Pullan D
Page 3 and 4: Threads, thread blocks and shared m
Page 5 and 6: Threads • Example in L1 made no u
Page 7 and 8: Kernel for c = a + b __global__ voi
Page 9 and 10: Threads, blocks and grid Block is s
Page 11 and 12: More on thread blocks • Thread bl
Page 13 and 14: Streaming multiprocessors and share
Page 15 and 16: Governing equation • Heat conduct
Page 17 and 18: 2D heat conduction • In 2D: ∂T
Page 19 and 20: Domain
Page 21 and 22: Results Initial field After 50000 s
Page 23 and 24: GPU strategy 1 • Start a thread f
Page 25 and 26: GPU strategy 1 - threads and blocks
Page 27 and 28: GPU strategy 1 - kernel launch code
Page 29 and 30: Performance • CPU - 1 core, Intel
Page 31 and 32: GPU strategy 2 - threads and blocks
Page 33: GPU strategy 2 - kernel (part 1) //
Page 37 and 38: GPU strategy 3 • Can use larger b
Page 39 and 40: GPU strategy 3
Page 45 and 46: Lecture 2 summary

Lecture 2 â Threads - many-core.group

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Lecture 2 â Threads - many-core.group