CUDA内核在CudaDeviceSynchronize之前未启动
我和CUDA有点问题。请看附件中的图片。内核在0.395秒的标记点启动。然后是一些绿色的彩画。最后,调用cudaDeviceSynchronize。在CpuWork之前启动的内核不会在同步调用之前启动。理想情况下,它应该与CPU工作并行运行CUDA内核在CudaDeviceSynchronize之前未启动,cuda,Cuda,我和CUDA有点问题。请看附件中的图片。内核在0.395秒的标记点启动。然后是一些绿色的彩画。最后,调用cudaDeviceSynchronize。在CpuWork之前启动的内核不会在同步调用之前启动。理想情况下,它应该与CPU工作并行运行 void KdTreeGpu::traceRaysOnGpuAsync(int firstRayIndex, int numRays, int rank, int buffer) { int per_block = 128; int num_
void KdTreeGpu::traceRaysOnGpuAsync(int firstRayIndex, int numRays, int rank, int buffer)
{
int per_block = 128;
int num_blocks = numRays/per_block + (numRays%per_block==0?0:1);
Ray* rays = &this->deviceRayPtr[firstRayIndex];
int* outputHitPanelIds = &this->deviceHitPanelIdPtr[firstRayIndex];
kdTreeTraversal<<<num_blocks, per_block, 0>>>(sceneBoundingBox, rays, deviceNodesPtr, deviceTrianglesListPtr,
firstRayIndex, numRays, rank, rootNodeIndex,
deviceTHitPtr, outputHitPanelIds, deviceReflectionPtr);
CUDA_VALIDATE(cudaMemcpyAsync(resultHitDistances[buffer], deviceTHitPtr, numRays*sizeof(double), cudaMemcpyDeviceToHost));
CUDA_VALIDATE(cudaMemcpyAsync(resultHitPanelIds[buffer], outputHitPanelIds, numRays*sizeof(int), cudaMemcpyDeviceToHost));
CUDA_VALIDATE(cudaMemcpyAsync(resultReflections[buffer], deviceReflectionPtr, numRays*sizeof(Vector3), cudaMemcpyDeviceToHost));
}
希望能解决这个问题。已经尝试了很多事情,包括不在默认流中运行。当我添加cudaHostAlloc时,我意识到异步方法返回到了CPU。但是当内核在稍后的deviceSynchronize调用之前没有启动时,这没有帮助
resultThitInstances[2]
包含两个分配的内存区域,因此当CPU读取0时,GPU应将结果放入1
谢谢
编辑:这是调用traceRaysAsync的代码
int numIterations = ceil(float(this->numPrimaryRays) / MAX_RAYS_PER_ITERATION);
int numRaysPrevious = min(MAX_RAYS_PER_ITERATION, this->numPrimaryRays);
nvtxRangePushA("traceRaysOnGpuAsync First");
traceRaysOnGpuAsync(0, numRaysPrevious, rank, 0);
nvtxRangePop();
for(int iteration = 0; iteration < numIterations; iteration++)
{
int rayFrom = (iteration+1)*MAX_RAYS_PER_ITERATION;
int rayTo = min((iteration+2)*MAX_RAYS_PER_ITERATION, this->numPrimaryRays) - 1;
int numRaysIteration = rayTo-rayFrom+1;
// Wait for results to finish and get them
waitForGpu();
// Trace the next iteration asynchronously. This will have data prepared for next iteration
if(numRaysIteration > 0)
{
int nextBuffer = (iteration+1) % 2;
nvtxRangePushA("traceRaysOnGpuAsync Interior");
traceRaysOnGpuAsync(rayFrom, numRaysIteration, rank, nextBuffer);
nvtxRangePop();
}
nvtxRangePushA("CpuWork");
// Store results for current iteration
int rayOffset = iteration*MAX_RAYS_PER_ITERATION;
int buffer = iteration % 2;
for(int i = 0; i < numRaysPrevious; i++)
{
if(this->activeRays[rayOffset+i] && resultHitPanelIds[buffer][i] >= 0)
{
this->activeRays[rayOffset+i] = false;
const TrianglePanelPair & t = this->getTriangle(resultHitPanelIds[buffer][i]);
double hitT = resultHitDistances[buffer][i];
Vector3 reflectedDirection = resultReflections[buffer][i];
Result res = Result(rays[rayOffset+i], hitT, t.panel);
results[rank].push_back(res);
t.panel->incrementIntensity(1.0);
if (t.panel->getParent().absorbtion < 1)
{
numberOfRaysGenerated++;
Ray reflected (res.endPoint() + 0.00001*reflectedDirection, reflectedDirection);
this->newRays[rayOffset+i] = reflected;
this->activeRays[rayOffset+i] = true;
numNewRays++;
}
}
}
numRaysPrevious = numRaysIteration;
nvtxRangePop();
}
int numIterations=ceil(浮动(此->numprimaryrayes)/MAX_RAYS每迭代一次);
int numRaysPrevious=min(每次迭代的最大光线数,此->numPrimaryRays);
nvtxRangePushA(“traceRaysOnGpuAsync优先”);
traceraysongpuanc(0,numRaysPrevious,rank,0);
nvtxRangePop();
for(int iteration=0;iterationnumPrimaryRays)-1;
int numraysiration=光线到光线自+1;
//等待结果完成并获取它们
waitpu();
//异步跟踪下一次迭代。这将为下一次迭代准备数据
如果(数值迭代>0)
{
int nextBuffer=(迭代+1)%2;
nvtxRangePushA(“traceRaysOnGpuAsync内饰”);
traceraysongpuanc(rayFrom、numRaysIteration、rank、nextBuffer);
nvtxRangePop();
}
nvtxRangePushA(“CpuWork”);
//存储当前迭代的结果
int raydoffset=迭代*每次迭代的最大光线数;
int buffer=迭代%2;
对于(int i=0;iactiveRays[raydoffset+i]&&resulthtpanelds[buffer][i]>=0)
{
此->activeRays[rayOffset+i]=false;
const TrianglePanelPair&t=this->getTriangle(resultThitPanelids[buffer][i]);
double hitT=结果状态[缓冲区][i];
Vector3 reflectedDirection=resultReflections[buffer][i];
结果res=结果(光线[光线偏移量+i],hitT,t面板);
结果[排名]。推回(res);
t、 面板->递增强度(1.0);
如果(t.panel->getParent().absorbtion<1)
{
生成的光线数++;
光线反射(res.endPoint()+0.00001*反射方向,反射方向);
这->新光线[rayOffset+i]=反射;
此->activeRays[rayOffset+i]=true;
numNewRays++;
}
}
}
numRaysPrevious=numRaysIteration;
nvtxRangePop();
}
这是WDDM驱动程序模型的Windows上的预期行为,驱动程序试图通过尝试批处理内核启动来减轻内核启动开销。尝试在内核调用之后直接插入cudaStreamQuery(0)
,以在批处理已满之前触发内核的提前启动。在KdTreeGpu::traceRaysOnGpuAsync调用之后没有显示代码,但这可能很有用,例如,可以查看在何处以及为什么使用cudaDeviceSynchronize()调用?我认为您是在调用KdTreeGpu::traceraysongpuancy之后立即发出devicesync,但这将消除重叠。这是您希望重叠的区域,假设第二个绿色的CpuWork条不依赖于kdTreeTraversal的结果,那么您希望在内核函数调用后立即移动或消除该devicesync。在devicesync之前重新考虑一些CpuWork。我添加了更多的代码,这些代码已经清除了一些计时器,因此应该更容易理解。这两个缓冲区应该使CPU独立于内核启动。为了避免与WDM驱动程序模型的性能问题,考虑切换到TCC驱动程序。一个内核之后和两个MeMeCon之后的一个操作。在内核之后只有一个内存,memcpy被延迟到syncrhonize。现在,它是在适当的平行。谢谢
int numIterations = ceil(float(this->numPrimaryRays) / MAX_RAYS_PER_ITERATION);
int numRaysPrevious = min(MAX_RAYS_PER_ITERATION, this->numPrimaryRays);
nvtxRangePushA("traceRaysOnGpuAsync First");
traceRaysOnGpuAsync(0, numRaysPrevious, rank, 0);
nvtxRangePop();
for(int iteration = 0; iteration < numIterations; iteration++)
{
int rayFrom = (iteration+1)*MAX_RAYS_PER_ITERATION;
int rayTo = min((iteration+2)*MAX_RAYS_PER_ITERATION, this->numPrimaryRays) - 1;
int numRaysIteration = rayTo-rayFrom+1;
// Wait for results to finish and get them
waitForGpu();
// Trace the next iteration asynchronously. This will have data prepared for next iteration
if(numRaysIteration > 0)
{
int nextBuffer = (iteration+1) % 2;
nvtxRangePushA("traceRaysOnGpuAsync Interior");
traceRaysOnGpuAsync(rayFrom, numRaysIteration, rank, nextBuffer);
nvtxRangePop();
}
nvtxRangePushA("CpuWork");
// Store results for current iteration
int rayOffset = iteration*MAX_RAYS_PER_ITERATION;
int buffer = iteration % 2;
for(int i = 0; i < numRaysPrevious; i++)
{
if(this->activeRays[rayOffset+i] && resultHitPanelIds[buffer][i] >= 0)
{
this->activeRays[rayOffset+i] = false;
const TrianglePanelPair & t = this->getTriangle(resultHitPanelIds[buffer][i]);
double hitT = resultHitDistances[buffer][i];
Vector3 reflectedDirection = resultReflections[buffer][i];
Result res = Result(rays[rayOffset+i], hitT, t.panel);
results[rank].push_back(res);
t.panel->incrementIntensity(1.0);
if (t.panel->getParent().absorbtion < 1)
{
numberOfRaysGenerated++;
Ray reflected (res.endPoint() + 0.00001*reflectedDirection, reflectedDirection);
this->newRays[rayOffset+i] = reflected;
this->activeRays[rayOffset+i] = true;
numNewRays++;
}
}
}
numRaysPrevious = numRaysIteration;
nvtxRangePop();
}