Stuck with CullingThreadPool

[nhy002]

The program got stuck when using CullingThreadPool, and going on with example code, I got the same problem after changing some code:

//FillrateTest.cpp line 424
for (int i = 0; i < numSizes; ++i)
{
	int size = sizes[i];
	//double t = BenchmarkTrianglesThreaded(verts[i], trisBtF[i], numTriangles[i], &ctp);
	//change triangle count to 100
	double t = BenchmarkTrianglesThreaded(verts[i], trisBtF[i], 100, &ctp);
	double GPixelsPerSecond = (double)numTriangles[i] * size*size / (2.0 * 1e9 * t);
	double MTrisPerSecond = (double)numTriangles[i] / (1e6 * t);
	printf("Tri: %3dx%3d - Time: %7.2f ms, MTris/s: %6.2f GPixels/s: %5.2f \n", size, size, t * 1000.0f, MTrisPerSecond, GPixelsPerSecond);
}

//CullingThreadpool.cpp line 187
void CullingThreadpool::RenderJobQueue::Reset()
{
	mWritePtr = 0;
	mBinningPtr = 0;

	for (unsigned int i = 0; i < mNumBins; ++i)
		mRenderPtrs[i] = 0;
	printf("checking...");  // just delay for a while using printf
	for (unsigned int i = 0; i < mMaxJobs; ++i)
	{
		mJobs[i].mBinningJobCompletedIdx = -1;
		mJobs[i].mBinningJobStartedIdx = -1;
	}
}

run FillrateTest

[lvvvmd]

same problem. stuck at flush, seem that Reset() work unexpectly where mWritePtr and mRenderPtrs are not reset at the same time.

[nhy002]

I‘ve solved the problem by changing the order of some code

//CullingThreadpool.cpp line 187
void CullingThreadpool::RenderJobQueue::Reset()
{
	mWritePtr = 0;
	mBinningPtr = 0;

	for (unsigned int i = 0; i < mNumBins; ++i)
		mRenderPtrs[i] = 0;

	for (unsigned int i = 0; i < mMaxJobs; ++i)
	{
		mJobs[i].mBinningJobCompletedIdx = -1;
		mJobs[i].mBinningJobStartedIdx = -1;
	}
}

//after fix
void CullingThreadpool::RenderJobQueue::Reset()
{
	mWritePtr = 0;
	mBinningPtr = 0;

	for (unsigned int i = 0; i < mMaxJobs; ++i)
	{
		mJobs[i].mBinningJobCompletedIdx = -1;
		mJobs[i].mBinningJobStartedIdx = -1;
	}
	
	//change the order
	for (unsigned int i = 0; i < mNumBins; ++i)
		mRenderPtrs[i] = 0;
}

There is another problem causing wrong culling result some object will be culled unexpected

//CullingThreadpool.cpp line 314
CullingThreadpool::CullingThreadpool(unsigned int numThreads, unsigned int binsW, unsigned int binsH, unsigned int maxJobs) :
	mNumThreads(numThreads),
	mMaxJobs(maxJobs),
	mBinsW(binsW),
	mBinsH(binsH),
	mKillThreads(false),
	mSuspendThreads(true),
	mNumSuspendedThreads(0),
	mModelToClipMatrices(maxJobs),
	mVertexLayouts(maxJobs),
	mMOC(nullptr)
{ ... }

//after fix
CullingThreadpool::CullingThreadpool(unsigned int numThreads, unsigned int binsW, unsigned int binsH, unsigned int maxJobs) :
	mNumThreads(numThreads),
	mMaxJobs(maxJobs),
	mBinsW(binsW),
	mBinsH(binsH),
	mKillThreads(false),
	mSuspendThreads(true),
	mNumSuspendedThreads(0),
	mModelToClipMatrices(maxJobs + 1),
	mVertexLayouts(maxJobs + 1),
	mMOC(nullptr)
{ ... }

finally，there are some threading problems can be found with turning on TSan on XCode I fixed these though they didn't cause perceptible problems

with fixing these problem, MOC with CullingThreadPool works fine in our engine

[lvvvmd]

Thanks a lot!