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// SPDX-License-Identifier: BSD-3-Clause
/*
* victory_saxpy.cu - SAXPY (y = a*x + y) over 1M floats, two alphas.
*
* Two back-to-back launches over a 4 MB buffer:
*
* y = 3.0 * x + y
* y = 0.25 * x + y
*
* The host replays the same two steps from the same inputs and verifies the
* device result element by element with a small tolerance (the device may
* contract multiply-add to FMA; the host may not).
*
* Output lines are stable and greppable:
*
* DEVICE <name> cc=<major>.<minor> sm=<count> mem=<bytes>
* SAXPY n=<count> launches=2 bad=<mismatches> csum=<sum>
* STATUS OK|FAIL
*
* Build with a static CUDA runtime (--cudart=static) so the guest only needs
* the driver's libcuda.so, not a CUDA toolkit installation:
*
* nvcc -O2 --cudart=static -o victory_saxpy victory_saxpy.cu
*
* Then, from the guest: /tmp/victory_saxpy
*/
#include <cstdio>
#include <cstdlib>
#include <cstdint>
#include <cmath>
#include <cuda_runtime.h>
#define CHECK(x) \
do { \
cudaError_t e_ = (x); \
if (e_ != cudaSuccess) { \
printf("CUDA_ERROR %s at line %d\n", \
cudaGetErrorString(e_), __LINE__); \
printf("STATUS FAIL\n"); \
return 1; \
} \
} while (0)
__global__ void saxpy(const float *x, float *y, float alpha, int n)
{
int i = blockIdx.x * blockDim.x + threadIdx.x;
if (i < n)
y[i] = alpha * x[i] + y[i];
}
int main(void)
{
cudaDeviceProp prop;
const int n = 1 << 20; /* 1M floats = 4 MB */
const float alpha1 = 3.0f, alpha2 = 0.25f;
size_t bytes = (size_t)n * sizeof(float);
float *h_x, *h_y0, *h_ref, *h_y;
float *d_x, *d_y;
double csum = 0.0;
int bad = 0, i;
setvbuf(stdout, NULL, _IONBF, 0);
CHECK(cudaGetDeviceProperties(&prop, 0));
printf("DEVICE %s cc=%d.%d sm=%d mem=%llu\n", prop.name,
prop.major, prop.minor, prop.multiProcessorCount,
(unsigned long long)prop.totalGlobalMem);
h_x = (float *)malloc(bytes);
h_y0 = (float *)malloc(bytes);
h_ref = (float *)malloc(bytes);
h_y = (float *)malloc(bytes);
if (!h_x || !h_y0 || !h_ref || !h_y)
return 1;
for (i = 0; i < n; i++) {
h_x[i] = (float)(i % 1000) * 0.5f;
h_y0[i] = (float)(i % 997) * 0.25f;
h_ref[i] = h_y0[i];
}
/* Host reference: the same two SAXPY steps, in the same order. */
for (i = 0; i < n; i++)
h_ref[i] = alpha1 * h_x[i] + h_ref[i];
for (i = 0; i < n; i++)
h_ref[i] = alpha2 * h_x[i] + h_ref[i];
CHECK(cudaMalloc(&d_x, bytes));
CHECK(cudaMalloc(&d_y, bytes));
CHECK(cudaMemcpy(d_x, h_x, bytes, cudaMemcpyHostToDevice));
CHECK(cudaMemcpy(d_y, h_y0, bytes, cudaMemcpyHostToDevice));
saxpy<<<(n + 255) / 256, 256>>>(d_x, d_y, alpha1, n);
saxpy<<<(n + 255) / 256, 256>>>(d_x, d_y, alpha2, n);
CHECK(cudaGetLastError());
CHECK(cudaDeviceSynchronize());
CHECK(cudaMemcpy(h_y, d_y, bytes, cudaMemcpyDeviceToHost));
for (i = 0; i < n; i++) {
float tol = 1e-3f + 1e-5f * fabsf(h_ref[i]);
if (fabsf(h_y[i] - h_ref[i]) > tol)
bad++;
csum += (double)h_y[i];
}
printf("SAXPY n=%d launches=2 bad=%d csum=%.6f\n", n, bad, csum);
if (bad != 0) {
printf("STATUS FAIL\n");
return 1;
}
printf("STATUS OK\n");
CHECK(cudaFree(d_x));
CHECK(cudaFree(d_y));
free(h_x);
free(h_y0);
free(h_ref);
free(h_y);
return 0;
}
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