import jcuda.*;
import jcuda.driver.*;

import static jcuda.driver.JCudaDriver.*;

public class StreamAttributeExample {
    public static void main(String[] args) {
        JCudaDriver.setExceptionsEnabled(true);

        // Initialize CUDA
        cuInit(0);

        CUdevice device = new CUdevice();
        cuDeviceGet(device, 0);

        CUcontext context = new CUcontext();
        cuCtxCreate(context, 0, device);

        // Create stream
        CUstream stream = new CUstream();
        cuStreamCreate(stream, 0);

        // Allocate some device memory
        CUdeviceptr ptr = new CUdeviceptr();
        long size = 1024 * 1024; // 1 MB
        cuMemAlloc(ptr, size);

        // --- Access policy window setup ---
        CUaccessPolicyWindow window = new CUaccessPolicyWindow();
        window.base_ptr = ptr;
        window.num_bytes = size;
        window.hitRatio = 1.0f;
        window.hitProp = CUaccessProperty.CU_ACCESS_PROPERTY_PERSISTING;
        window.missProp = CUaccessProperty.CU_ACCESS_PROPERTY_STREAMING;

        // --- Attribute wrapper (IMPORTANT) ---
        CUstreamAttrValue attr = new CUstreamAttrValue();

        // Only set the field corresponding to the attribute!
        attr.accessPolicyWindow = window;

        // --- Apply attribute ---
        int result = cuStreamSetAttribute(
            stream,
            CUstreamAttrID.CU_STREAM_ATTRIBUTE_ACCESS_POLICY_WINDOW,
            attr
        );

        if (result != CUresult.CUDA_SUCCESS) {
            System.out.println("Error: " + CUresult.stringFor(result));
        }

        // Cleanup
        cuMemFree(ptr);
        cuStreamDestroy(stream);
        cuCtxDestroy(context);
    }
}

# A fatal error has been detected by the Java Runtime Environment: 
# SIGSEGV (0xb) at pc=0x00007c9a7e3af9db, pid=620345, tid=620352 
# JRE version: OpenJDK Runtime Environment (21.0.10+7) (build 21.0.10+7-Ubuntu-124.04) 
# Java VM: OpenJDK 64-Bit Server VM (21.0.10+7-Ubuntu-124.04, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64) 
# Problematic frame: # V [libjvm.so+0x9af9db] jni_GetLongField+0xab

FATAL ERROR in native method: Wrong field ID passed to JNI