Sync HIP documentation 2025-10-20 (#1258)

* Add examples to tools folder
* Correct P2P memory access section
* Sync poriting guide
* Add HIP Graph tutorial
* Add hint about using amdgpu-dkms for IPC API
* Add a few more env variables

projects/hip/docs/tools/example_codes/block_reduction.cu

@@ -0,0 +1,110 @@
+// MIT License
+//
+// Copyright (c) 2025 Advanced Micro Devices, Inc. All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+// [sphinx-start]
+#include <cuda_runtime.h>
+
+#include <iostream>
+#include <vector>
+
+__global__ void block_reduction(const float* input, float* output, int num_elements)
+{
+    extern __shared__ float s_data[];
+
+    int tid = threadIdx.x;
+    int global_id = blockDim.x * blockIdx.x + tid;
+
+    if (global_id < num_elements)
+    {
+        s_data[tid] = input[global_id];
+    }
+    else
+    {
+        s_data[tid] = 0.0f;
+    }
+    __syncthreads();
+
+    for (int stride = blockDim.x / 2; stride > 0; stride >>= 1)
+    {
+        if (tid < stride)
+        {
+            s_data[tid] += s_data[tid + stride];
+        }
+        __syncthreads();
+    }
+
+    if (tid == 0)
+    {
+        output[blockIdx.x] = s_data[0];
+    }
+}
+
+int main()
+{
+    int threads = 256;
+    const int num_elements = 50000;
+
+    std::vector<float> h_a(num_elements);
+    std::vector<float> h_b((num_elements + threads - 1) / threads);
+
+    for (int i = 0; i < num_elements; ++i)
+    {
+        h_a[i] = rand() / static_cast<float>(RAND_MAX);
+    }
+
+    float *d_a, *d_b;
+    cudaMalloc(&d_a, h_a.size() * sizeof(float));
+    cudaMalloc(&d_b, h_b.size() * sizeof(float));
+
+    cudaStream_t stream;
+    cudaStreamCreateWithFlags(&stream, cudaStreamNonBlocking);
+
+    cudaEvent_t start_event, stop_event;
+    cudaEventCreate(&start_event);
+    cudaEventCreate(&stop_event);
+
+    cudaMemcpyAsync(d_a, h_a.data(), h_a.size() * sizeof(float), cudaMemcpyHostToDevice, stream);
+
+    cudaEventRecord(start_event, stream);
+
+    int blocks = (num_elements + threads - 1) / threads;
+    block_reduction<<<blocks, threads, threads * sizeof(float), stream>>>(d_a, d_b, num_elements);
+
+    cudaMemcpyAsync(h_b.data(), d_b, h_b.size() * sizeof(float), cudaMemcpyDeviceToHost, stream);
+
+    cudaEventRecord(stop_event, stream);
+    cudaEventSynchronize(stop_event);
+
+    float milliseconds = 0.f;
+    cudaEventElapsedTime(&milliseconds, start_event, stop_event);
+    std::cout << "Kernel execution time: " << milliseconds << " ms\n";
+
+    cudaFree(d_a);
+    cudaFree(d_b);
+
+    cudaEventDestroy(start_event);
+    cudaEventDestroy(stop_event);
+    cudaStreamDestroy(stream);
+
+    return 0;
+}
+// [sphinx-end]