OptiX CUDA Interop With 3080

Attempting to use UPLOAD_WITH_CUDA,BUFFER_COPY_ON_DIRTY OR BUFFER_COPY_ON_DIRTY with the seed buffer in 3080 yields a hard CUDA crash on 2nd event launch, even with dumpseed.

Success in 3080 with okop-/tests/dirtyBufferTest made me get rid of UPLOAD_WITH_CUDA,BUFFER_COPY_ON_DIRTY.

Initially however the stuck at zero issue remained

FIX

The below commit succeeds to fix issue.

• https://bitbucket.org/simoncblyth/opticks/commits/7387baedddb53897a4d710b0a59b78157efec6de

Initially it looked like the use of a prelaunch between gensteps upload and seeding was the reason for success, but subsequently it is operational without that... so there is some other cause.

Examining the commit the other significant change is to not try to download the OPTIX_INPUT_ONLY seed buffer. And remove the BUFFER_COPY_ON_DIRTY from seed buffer. Potentially those messed things up ?

Reference

open /Developer/OptiX_380/doc/OptiX_Programming_Guide_3.8.0.pdf

Overview of seeding interop

Seeding OpSeeder::seedPhotonsFromGenstepsImp is done via Thrust, dumping seed buffer shows is as expected on all events, but it is only seen by OptiX on the first:

254 #ifdef WITH_SEED_BUFFER
255     tox.dump<unsigned int>("OpSeeder::seedPhotonsFromGenstepsImp tox.dump", 1*1, 0, num_photons ); // stride, begin, end
256 #endif

Try skipping the seed buffer zero ahead, makes no difference.

So problem is Thrust to OptiX handover.

052 void OpSeeder::seedPhotonsFromGensteps()
 53 {
 54     LOG(info)<<"OpSeeder::seedPhotonsFromGensteps" ;
 55     if( m_ocontext->isInterop() )
 56     {
 57 #ifdef WITH_SEED_BUFFER
 58         seedComputeSeedsFromInteropGensteps();
 59 #else
 60         seedPhotonsFromGenstepsViaOpenGL();
 61 #endif
 62     }
 63     else if ( m_ocontext->isCompute() )
 64     {
 65         seedPhotonsFromGenstepsViaOptiX();
 66     }
 67     if(m_hub->hasOpt("onlyseed")) exit(EXIT_SUCCESS);
 68 }




022 CBufSlice OBufBase::slice( unsigned int stride, unsigned int begin, unsigned int end )
 23 {
 24    return CBufSlice( getDevicePtr(), getSize(), getNumBytes(), stride, begin, end == 0u ? getNumAtoms() : end);
 25 }
 26
 27 CBufSpec OBufBase::bufspec()
 28 {
 29    return CBufSpec( getDevicePtr(), getSize(), getNumBytes()) ;
 30 }

/// CBufSpec is just a holder for dev_ptr together with size and numBytes


175 void* OBufBase::getDevicePtr()
176 {
177     //printf("OBufBase::getDevicePtr %s \n", ( m_name ? m_name : "-") ) ;
178     //return (void*) m_buffer->getDevicePointer(m_device);
179
180     CUdeviceptr cu_ptr = (CUdeviceptr)m_buffer->getDevicePointer(m_device) ;
181     return (void*)cu_ptr ;
182 }





141 void OpSeeder::seedPhotonsFromGenstepsViaOptiX()
142 {
143     OK_PROFILE("_OpSeeder::seedPhotonsFromGenstepsViaOptiX");
144
145     OBuf* genstep = m_oevt->getGenstepBuf() ;
146     CBufSpec s_gs = genstep->bufspec();     /// just a holder for dev_ptr, size, num_bytes
147
148 #ifdef WITH_SEED_BUFFER
149     LOG(info) << "OpSeeder::seedPhotonsFromGenstepsViaOptiX : SEEDING TO SEED BUF  " ;
150     OBuf* seed = m_oevt->getSeedBuf() ;
151     CBufSpec s_se = seed->bufspec();  //  optix::Buffer::getDevicePointer happens here
152     seedPhotonsFromGenstepsImp(s_gs, s_se);
153     //s_gs.Summary("OpSeeder::seedPhotonsFromGenstepsViaOptiX (CBufSpec)s_gs");
154     //s_se.Summary("OpSeeder::seedPhotonsFromGenstepsViaOptiX (CBufSpec)s_se");
155 #else
156     LOG(info) << "OpSeeder::seedPhotonsFromGenstepsViaOptiX : seeding to photon buf  " ;
157     OBuf* photon = m_oevt->getPhotonBuf() ;
158     CBufSpec s_ox = photon->bufspec();
159     seedPhotonsFromGenstepsImp(s_gs, s_ox);
160 #endif
161
162     //genstep->Summary("OpSeeder::seedPhotonsFromGenstepsViaOptiX (OBuf)genstep");
163     //s_gs.Summary("OpSeeder::seedPhotonsFromGenstepsViaOptiX (CBufSpec)s_gs");
164
165     //photon->Summary("OpSeeder::seedPhotonsFromGenstepsViaOptiX (OBuf)photon ");
166     //s_ox.Summary("OpSeeder::seedPhotonsFromGenstepsViaOptiX (CBufSpec)s_ox");
167
168
169
170     TIMER("seedPhotonsFromGenstepsViaOptiX");
171     OK_PROFILE("OpSeeder::seedPhotonsFromGenstepsViaOptiX");
172
173 }





208 void OpSeeder::seedPhotonsFromGenstepsImp(const CBufSpec& s_gs, const CBufSpec& s_ox)
209 {
210     //s_gs.Summary("OpSeeder::seedPhotonsFromGenstepsImp (CBufSpec)s_gs");
211     //s_ox.Summary("OpSeeder::seedPhotonsFromGenstepsImp (CBufSpec)s_ox");
212
213     TBuf tgs("tgs", s_gs );
214     TBuf tox("tox", s_ox );

19 TBuf::TBuf(const char* name, CBufSpec spec ) :
20         m_name(strdup(name)),
21         m_spec(spec)
22 {
23 }
24
25 CBufSlice TBuf::slice( unsigned int stride, unsigned int begin, unsigned int end ) const
26 {
27     if(end == 0u) end = m_spec.size ;
28     return CBufSlice(m_spec.dev_ptr, m_spec.size, m_spec.num_bytes, stride, begin, end);
29 }
..
36 void* TBuf::getDevicePtr() const
37 {
38     return m_spec.dev_ptr ;
39 }