Closed GoogleCodeExporter closed 9 years ago
GoogleCodeExporter
commented
9 years ago Essentially I'd like to see a toy example of linking in CUBLAS and have it run
against the ocelot emulator is some provable fashion. Maybe having a
deliberate out of bounds memory assignment and having ocelot catch it or
something. I'd want to see the command line that compiles and links said test
application.Original comment by mcbromb...@gmail.com on 21 Oct 2010 at 4:49
GoogleCodeExporter
commented
9 years ago [deleted comment]Try giving this simple example a go:
--- begin source code ---
/*!
\file simplerCUFFTdriver.cpp
\author Andrew Kerr <arkerr@gatech.edu>
\brief implements the simplerCUFFT application using the CUDA runtime API
*/
#include <stdio.h>
#include <stdlib.h>
#include <cufft.h>
#include <cuda_runtime.h>
/*!
computes the N-point DFT of signal X and stores in Y
*/
bool host_dft(cuComplex *Y, cuComplex *X, float scale, int N) {
const float Pi = 3.14159265358979f;
for (int n = 0; n < N; n++) {
cuComplex X_n = {0, 0};
for (int k = 0; k < N; k++) {
float w = -2.0f * Pi / (float)N * (float)n * (float)k;
cuComplex e = {(float)cos(w), (float)sin(w)};
cuComplex x_k = X[k];
X_n.x += e.x * x_k.x - e.y * x_k.y;
X_n.y += e.y * x_k.x + e.x * x_k.y;
}
X_n.x *= scale;
X_n.y *= scale;
Y[n] = X_n;
}
return true;
}
/*!
computes the N-point DFT of signal X and stores in Y using CUDA's FFT library
*/
bool cuda_dft(cuComplex *Y, cuComplex *X, float scale, int N) {
size_t bytes = (size_t)N * sizeof(cuComplex);
cuComplex *Y_gpu, *X_gpu;
cudaMalloc((void **)&Y_gpu, bytes);
cudaMalloc((void **)&X_gpu, bytes);
cudaMemcpy(Y_gpu, Y, bytes, cudaMemcpyHostToDevice);
cudaMemcpy(X_gpu, X, bytes, cudaMemcpyHostToDevice);
cufftHandle plan;
cufftPlan1d(&plan, N, CUFFT_C2C, 1);
cufftExecC2C(plan, X_gpu, Y_gpu, CUFFT_FORWARD);
cufftDestroy(plan);
cudaMemcpy(Y, Y_gpu, bytes, cudaMemcpyDeviceToHost);
cudaFree(Y_gpu);
cudaFree(X_gpu);
for (int n = 0; n < N; n++) {
Y[n].x *= scale;
Y[n].y *= scale;
}
return true;
}
int main(int argc, char *arg[]) {
int N = 32;
size_t bytes = (size_t)N * sizeof(cuComplex);
cuComplex *X, *Y_ref, *Y_exp;
X = (cuComplex *)malloc(bytes);
Y_ref = (cuComplex *)malloc(bytes);
Y_exp = (cuComplex *)malloc(bytes);
//
// initialize data
//
srand(2009);
for (int n = 0; n < N; n++) {
X[n].x = (float)(rand() % 1000) / 500.0f - 1.0f;
X[n].y = (float)((rand()+7) % 1000) / 500.0f - 1.0f;
Y_ref[n].x = 0;
Y_ref[n].y = 0;
Y_exp[n].x = 0;
Y_exp[n].y = 0;
}
//
// perform DFTs
//
host_dft(Y_ref, X, 1.0f, N);
cuda_dft(Y_exp, X, 1.0f, N);
//
// compare results
//
int errors = 0;
for (int n = 0; (errors < 10) && n < N; n++) {
cuComplex e = Y_ref[n], g = Y_exp[n];
cuComplex error = {e.x - g.x, e.y - g.y};
float mag_sq_error = error.x * error.x + error.y * error.y;
if (mag_sq_error >= 0.000001f) {
// error on element n
++errors;
printf("[n=%d]: expected (%f+%fi), got (%f+%fi)\n", n, e.x, e.y, g.x, g.y);
}
}
printf("DFT %s\n", (errors ? "FAILED" : "passed"));
//
// cleanup
//
free(X);
free(Y_ref);
free(Y_exp);
return 0;
}
--- end source code -----
To compile this example, make sure that ocelot is installed correctly:
normal@phenom:~/checkout/gpuocelot/tests/cuda2.2/tests/simplerCUFFT$
OcelotConfig -v
1.2.603
Compile the application, link against ocelot and cufft:
normal@phenom:~/checkout/gpuocelot/tests/cuda2.2/tests/simplerCUFFT$ g++
simplerCUFFT.cpp -o simplercufft -g -lcufft `OcelotConfig -l` -I
/usr/local/cuda/include/ -L /usr/local/cuda/lib64/
Run the application:
normal@phenom:~/checkout/gpuocelot/tests/cuda2.2/tests/simplerCUFFT$
./simplercufft
DFT passed
Verify that you are running on the emulator. Make sure that the debugger is
enabled in configure.ocelot and that the emulator is selected.
--- begin configure.ocelot ---
{
ocelot: "ocelot",
trace: {
memoryChecker: false,
raceDetector: {
enabled: false,
ignoreIrrelevantWrites: true
},
debugger: {
enabled: true,
kernelFilter: "",
alwaysAttach: true
}
},
cuda: {
implementation: CudaRuntime,
runtimeApiTrace: "trace/CudaAPI.trace"
},
executive: {
devices: [ emulated ],
optimizationLevel: none,
workerThreadLimit: 2
}
}
--- end configure.ocelot -----
Run the program again:
normal@phenom:~/checkout/gpuocelot/tests/cuda2.2/tests/simplerCUFFT$
./simplercufft
Step through the program using the emulator:
--- begin emulator output ---
normal@phenom:~/checkout/gpuocelot/tests/cuda2.2/tests/simplerCUFFT$
./simplercufft
(ocelot-dbg) Attaching debugger to kernel
'_Z20fftSmemRadix2_kernelP6float2S0_jf'
(ocelot-dbg) s
(0) - mov.u64 %r0, s_data
(ocelot-dbg) s
(1) - ld.param.f32 %r1,
[__cudaparm__Z20fftSmemRadix2_kernelP6float2S0_jf___val_paramphaseBase + 20]
(ocelot-dbg) s
(2) - ld.param.u32 %r2,
[__cudaparm__Z20fftSmemRadix2_kernelP6float2S0_jf_vectorSize + 16]
(ocelot-dbg) s
(3) - cvt.u64.u32 %r3, %tid.x
(ocelot-dbg) s
(4) - mov.s32 %r4, %tid.x
(ocelot-dbg) p a
(5) - mul.wide.u32 %r5, %r4, 8
(6) - cvt.u32.u64 %r6, %r3
(7) - mov.u32 %r7, %ctaid.x
(8) - mul.lo.u32 %r8, %r7, %r2
(9) - cvt.u64.u32 %r9, %r8
(10) - mul.wide.u32 %r10, %r8, 8
(11) - ld.param.u64 %r11,
[__cudaparm__Z20fftSmemRadix2_kernelP6float2S0_jf___val_paramd_Src + 8]
(12) - add.u64 %r12, %r11, %r10
(13) - cvt.u64.u32 %r13, %r6
(14) - mul.wide.u32 %r14, %r6, 8
(ocelot-dbg) p r
THREAD 0 THREAD 1 THREAD 2 THREAD 3 THREAD 4
R0 0 0 0 0
0
R1 be490fdb be490fdb be490fdb be490fdb
be490fdb
R2 20 20 20 20
20
R3 0 1 2 3
4
R4 0 1 2 3
4
R5 0 0 0 0
0
R6 0 0 0 0
0
R7 0 0 0 0
0
R8 0 0 0 0
0
R9 0 0 0 0
0
(ocelot-dbg)
--- end emulator output ----
Original comment by gregory....@gatech.edu on 19 Nov 2010 at 1:46
Original issue reported on code.google.com by
mcbromb...@gmail.comon 20 Oct 2010 at 10:53