cuda-samples/Samples/3_CUDA_Features/graphConditionalNodes/graphConditionalNodes.cu
2024-04-10 19:44:42 +00:00

357 lines
13 KiB
Plaintext

/* Copyright (c) 2023, NVIDIA CORPORATION. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of NVIDIA CORPORATION nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* This file demonstrates the usage of conditional graph nodes with
* a series of *simple* example graphs.
*
* For more information on conditional nodes, see the programming guide:
*
* https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#conditional-graph-nodes
*
*/
// System includes
#include <cassert>
#include <cstdio>
// CUDA runtime
#include <cuda_runtime.h>
// helper functions and utilities to work with CUDA
#include <helper_cuda.h>
#include <helper_functions.h>
/*
* Create a graph containing two nodes.
* The first node, A, is a kernel and the second node, B, is a conditional IF node.
* The kernel sets the condition variable to true if a device memory location
* contains an odd number. Otherwise the condition variable is set to false.
* There is a single kernel, C, within the conditional body which prints a message.
*
* A -> B [ C ]
*
*/
__global__ void ifGraphKernelA(char *dPtr, cudaGraphConditionalHandle handle)
{
// In this example, condition is set if *dPtr is odd
unsigned int value = *dPtr & 0x01;
cudaGraphSetConditional(handle, value);
printf("GPU: Handle set to %d\n", value);
}
// This kernel will only be executed if the condition is true
__global__ void ifGraphKernelC(void)
{
printf("GPU: Hello from the GPU!\n");
}
// Setup and launch the graph
void simpleIfGraph(void)
{
cudaGraph_t graph;
cudaGraphExec_t graphExec;
cudaGraphNode_t node;
void *kernelArgs[2];
// Allocate a byte of device memory to use as input
char *dPtr;
checkCudaErrors(cudaMalloc((void**)&dPtr, 1));
printf("simpleIfGraph: Building graph...\n");
cudaGraphCreate(&graph, 0);
// Create conditional handle.
cudaGraphConditionalHandle handle;
cudaGraphConditionalHandleCreate(&handle, graph);
// Use a kernel upstream of the conditional to set the handle value
cudaGraphNodeParams params = { cudaGraphNodeTypeKernel };
params.kernel.func = (void *)ifGraphKernelA;
params.kernel.gridDim.x = params.kernel.gridDim.y = params.kernel.gridDim.z = 1;
params.kernel.blockDim.x = params.kernel.blockDim.y = params.kernel.blockDim.z = 1;
params.kernel.kernelParams = kernelArgs;
kernelArgs[0] = &dPtr;
kernelArgs[1] = &handle;
checkCudaErrors(cudaGraphAddNode(&node, graph, NULL, 0, &params));
cudaGraphNodeParams cParams = { cudaGraphNodeTypeConditional };
cParams.conditional.handle = handle;
cParams.conditional.type = cudaGraphCondTypeIf;
cParams.conditional.size = 1;
checkCudaErrors(cudaGraphAddNode(&node, graph, &node, 1, &cParams));
cudaGraph_t bodyGraph = cParams.conditional.phGraph_out[0];
// Populate the body of the conditional node
cudaGraphNode_t bodyNode;
params.kernel.func = (void *)ifGraphKernelC;
params.kernel.kernelParams = nullptr;
checkCudaErrors(cudaGraphAddNode(&bodyNode, bodyGraph, NULL, 0, &params));
checkCudaErrors(cudaGraphInstantiate(&graphExec, graph, NULL, NULL, 0));
// Initialize device memory and launch the graph
checkCudaErrors(cudaMemset(dPtr, 0, 1)); // Set dPtr to 0
printf("Host: Launching graph with conditional value set to false\n");
checkCudaErrors(cudaGraphLaunch(graphExec, 0));
checkCudaErrors(cudaDeviceSynchronize());
// Initialize device memory and launch the graph
checkCudaErrors(cudaMemset(dPtr, 1, 1)); // Set dPtr to 1
printf("Host: Launching graph with conditional value set to true\n");
checkCudaErrors(cudaGraphLaunch(graphExec, 0));
checkCudaErrors(cudaDeviceSynchronize());
// Cleanup
checkCudaErrors(cudaGraphExecDestroy(graphExec));
checkCudaErrors(cudaGraphDestroy(graph));
checkCudaErrors(cudaFree(dPtr));
printf("simpleIfGraph: Complete\n\n");
}
/*
* Create a graph containing a single conditional while node.
* The default value of the conditional variable is set to true, so this
* effectively becomes a do-while loop as the conditional body will always
* execute at least once. The body of the conditional contains 3 kernel nodes:
* A [ B -> C -> D ]
* Nodes B and C are just dummy nodes for demonstrative purposes. Node D
* will decrement a device memory location and set the condition value to false
* when the value reaches zero, terminating the loop.
* In this example, stream capture is used to populate the conditional body.
*/
// This kernel will only be executed if the condition is true
__global__ void doWhileEmptyKernel(void)
{
printf("GPU: doWhileEmptyKernel()\n");
return;
}
__global__ void doWhileLoopKernel(char *dPtr, cudaGraphConditionalHandle handle)
{
if (--(*dPtr) == 0) {
cudaGraphSetConditional(handle, 0);
}
printf("GPU: counter = %d\n", *dPtr);
}
void simpleDoWhileGraph(void)
{
cudaGraph_t graph;
cudaGraphExec_t graphExec;
cudaGraphNode_t node;
// Allocate a byte of device memory to use as input
char *dPtr;
checkCudaErrors(cudaMalloc((void**)&dPtr, 1));
printf("simpleDoWhileGraph: Building graph...\n");
checkCudaErrors(cudaGraphCreate(&graph, 0));
cudaGraphConditionalHandle handle;
checkCudaErrors(cudaGraphConditionalHandleCreate(&handle, graph, 1, cudaGraphCondAssignDefault));
cudaGraphNodeParams cParams = { cudaGraphNodeTypeConditional };
cParams.conditional.handle = handle;
cParams.conditional.type = cudaGraphCondTypeWhile;
cParams.conditional.size = 1;
checkCudaErrors(cudaGraphAddNode(&node, graph, NULL, 0, &cParams));
cudaGraph_t bodyGraph = cParams.conditional.phGraph_out[0];
cudaStream_t captureStream;
checkCudaErrors(cudaStreamCreate(&captureStream));
checkCudaErrors(cudaStreamBeginCaptureToGraph(captureStream, bodyGraph, nullptr, nullptr, 0, cudaStreamCaptureModeRelaxed));
doWhileEmptyKernel<<<1, 1, 0, captureStream>>>();
doWhileEmptyKernel<<<1, 1, 0, captureStream>>>();
doWhileLoopKernel<<<1, 1, 0, captureStream>>>(dPtr, handle);
checkCudaErrors(cudaStreamEndCapture(captureStream, nullptr));
checkCudaErrors(cudaStreamDestroy(captureStream));
checkCudaErrors(cudaGraphInstantiate(&graphExec, graph, NULL, NULL, 0));
// Initialize device memory and launch the graph
checkCudaErrors(cudaMemset(dPtr, 10, 1)); // Set dPtr to 10
printf("Host: Launching graph with loop counter set to 10\n");
checkCudaErrors(cudaGraphLaunch(graphExec, 0));
checkCudaErrors(cudaDeviceSynchronize());
// Cleanup
checkCudaErrors(cudaGraphExecDestroy(graphExec));
checkCudaErrors(cudaGraphDestroy(graph));
checkCudaErrors(cudaFree(dPtr));
printf("simpleDoWhileGraph: Complete\n\n");
}
/*
* Create a graph containing a conditional while loop using stream capture.
* This demonstrates how to insert a conditional node into a stream which is
* being captured. The graph consists of a kernel node followed by a conditional
* while node which contains a single kernel node:
*
* A -> B [ C ]
*
* The same kernel will be used for both nodes A and C. This kernel will test
* a device memory location and set the condition when the location is non-zero.
* We must run the kernel before the loop as well as inside the loop in order
* to behave like a while loop. We need to evaluate the device memory location
* before the conditional node is evaluated in order to set the condition variable
* properly. Because we're using a kernel upstream of the conditional node,
* there is no need to use the handle default value to initialize the conditional
* value.
*/
__global__ void capturedWhileKernel(char *dPtr, cudaGraphConditionalHandle handle)
{
printf("GPU: counter = %d\n", *dPtr);
if (*dPtr) {
(*dPtr)--;
}
cudaGraphSetConditional(handle, *dPtr);
}
__global__ void capturedWhileEmptyKernel(void)
{
printf("GPU: capturedWhileEmptyKernel()\n");
return;
}
void capturedWhileGraph(void)
{
cudaGraph_t graph;
cudaGraphExec_t graphExec;
cudaStreamCaptureStatus status;
const cudaGraphNode_t *dependencies;
size_t numDependencies;
// Allocate a byte of device memory to use as input
char *dPtr;
checkCudaErrors(cudaMalloc((void**)&dPtr, 1));
printf("capturedWhileGraph: Building graph...\n");
cudaStream_t captureStream;
checkCudaErrors(cudaStreamCreate(&captureStream));
checkCudaErrors(cudaStreamBeginCapture(captureStream, cudaStreamCaptureModeRelaxed));
// Obtain the handle of the graph
checkCudaErrors(cudaStreamGetCaptureInfo(captureStream, &status, NULL, &graph, &dependencies, &numDependencies));
// Create the conditional handle
cudaGraphConditionalHandle handle;
checkCudaErrors(cudaGraphConditionalHandleCreate(&handle, graph));
// Insert kernel node A
capturedWhileKernel<<<1, 1, 0, captureStream>>>(dPtr, handle);
// Obtain the handle for node A
checkCudaErrors(cudaStreamGetCaptureInfo(captureStream, &status, NULL, &graph, &dependencies, &numDependencies));
// Insert conditional node B
cudaGraphNode_t node;
cudaGraphNodeParams cParams = { cudaGraphNodeTypeConditional };
cParams.conditional.handle = handle;
cParams.conditional.type = cudaGraphCondTypeWhile;
cParams.conditional.size = 1;
checkCudaErrors(cudaGraphAddNode(&node, graph, dependencies, numDependencies, &cParams));
cudaGraph_t bodyGraph = cParams.conditional.phGraph_out[0];
// Update stream capture dependencies to account for the node we manually added
checkCudaErrors(cudaStreamUpdateCaptureDependencies(captureStream, &node, 1, cudaStreamSetCaptureDependencies));
// Insert kernel node D
capturedWhileEmptyKernel<<<1, 1, 0, captureStream>>>();
checkCudaErrors(cudaStreamEndCapture(captureStream, &graph));
checkCudaErrors(cudaStreamDestroy(captureStream));
// Populate conditional body graph using stream capture
cudaStream_t bodyStream;
checkCudaErrors(cudaStreamCreate(&bodyStream));
checkCudaErrors(cudaStreamBeginCaptureToGraph(bodyStream, bodyGraph, nullptr, nullptr, 0, cudaStreamCaptureModeRelaxed));
// Insert kernel node C
capturedWhileKernel<<<1, 1, 0, bodyStream>>>(dPtr, handle);
checkCudaErrors(cudaStreamEndCapture(bodyStream, nullptr));
checkCudaErrors(cudaStreamDestroy(bodyStream));
checkCudaErrors(cudaGraphInstantiate(&graphExec, graph, NULL, NULL, 0));
// Initialize device memory and launch the graph
// Device memory is zero, so the conditional node will not execute
checkCudaErrors(cudaMemset(dPtr, 0, 1)); // Set dPtr to 0
printf("Host: Launching graph with loop counter set to 0\n");
checkCudaErrors(cudaGraphLaunch(graphExec, 0));
checkCudaErrors(cudaDeviceSynchronize());
// Initialize device memory and launch the graph
checkCudaErrors(cudaMemset(dPtr, 10, 1)); // Set dPtr to 10
printf("Host: Launching graph with loop counter set to 10\n");
checkCudaErrors(cudaGraphLaunch(graphExec, 0));
checkCudaErrors(cudaDeviceSynchronize());
// Cleanup
checkCudaErrors(cudaGraphExecDestroy(graphExec));
checkCudaErrors(cudaGraphDestroy(graph));
checkCudaErrors(cudaFree(dPtr));
printf("capturedWhileGraph: Complete\n\n");
}
int main(int argc, char **argv) {
int device = findCudaDevice(argc, (const char **)argv);
int driverVersion = 0;
cudaDriverGetVersion(&driverVersion);
printf("Driver version is: %d.%d\n", driverVersion / 1000,
(driverVersion % 100) / 10);
if (driverVersion < 12030) {
printf("Waiving execution as driver does not support Graph Conditional Nodes\n");
exit(EXIT_WAIVED);
}
simpleIfGraph();
simpleDoWhileGraph();
capturedWhileGraph();
return 0;
}