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Adds multithreading support for batch ray casts.

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To enable the feature, enable the BULLET2_MULTITHREADING option.

Increases the number of rays that can go in a batch request by storing
them in the shared memory stream instead of the shared memory command.
Adds the API b3RaycastBatchSetNumThreads to specify the number of
threads to use for the raycast batch, also adds the argument numThreads
to the pybullet function rayTestBatch.
Rays are distributed among the threads in a greedy fashion there's a shared
queue of work, once a thread finishes its task, it picks the next
available ray from the task. This works better than pre-distributing the
rays among threads, since there's a large variance in computation time per ray.

Some controversial changes:
- Added a pointer to PhysicsClient to the SharedMemoryCommand struct, this
was necessary to keep the C-API the same for b3RaycastBatchAddRay, while
adding the ray to the shared memory stream instead of the command
struct. I think this may be useful to simplify other APIs as well, that
take both a client handle and a command handle.
- Moved #define SHARED_MEMORY_MAX_STREAM_CHUNK_SIZE to
SharedMemoryPublic. This was necessary for the definition of
MAX_RAY_INTERSECTION_BATCH_SIZE.
This commit is contained in:
Tigran Gasparian
2018-06-15 16:47:04 +02:00
parent 997211650e
commit 08409cae9f
13 changed files with 213 additions and 75 deletions
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18
examples/SharedMemory/SharedMemoryCommands.h
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@@ -23,12 +23,6 @@
typedef unsigned long long int smUint64_t;
#endif
#ifdef __APPLE__
#define SHARED_MEMORY_MAX_STREAM_CHUNK_SIZE (512*1024)
#else
#define SHARED_MEMORY_MAX_STREAM_CHUNK_SIZE (8*1024*1024)
#endif
#define SHARED_MEMORY_SERVER_TEST_C
#define MAX_DEGREE_OF_FREEDOM 128
#define MAX_NUM_SENSORS 256
@@ -38,6 +32,7 @@
#define MAX_NUM_LINKS MAX_DEGREE_OF_FREEDOM
#define MAX_USER_DATA_KEY_LENGTH MAX_URDF_FILENAME_LENGTH
struct TmpFloat3
{
float m_x;
@@ -279,15 +274,19 @@ enum EnumRequestContactDataUpdateFlags
struct RequestRaycastIntersections
{
// The number of threads that Bullet may use to perform the ray casts.
// 0: Let Bullet decide
// 1: Use a single thread (i.e. no multi-threading)
// 2 or more: Number of threads to use.
int m_numThreads;
int m_numRays;
double m_rayFromPositions[MAX_RAY_INTERSECTION_BATCH_SIZE][3];
double m_rayToPositions[MAX_RAY_INTERSECTION_BATCH_SIZE][3];
// Actual ray data stored in m_bulletStreamDataServerToClientRefactor.
};
struct SendRaycastHits
{
int m_numRaycastHits;
b3RayHitInfo m_rayHits[MAX_RAY_INTERSECTION_BATCH_SIZE];
// Actual ray data stored in m_bulletStreamDataServerToClientRefactor.
};
struct RequestContactDataArgs
@@ -1010,6 +1009,7 @@ struct SharedMemoryCommand
int m_type;
smUint64_t m_timeStamp;
int m_sequenceNumber;
struct PhysicsClient *m_client;
//m_updateFlags is a bit fields to tell which parameters need updating
//for example m_updateFlags = SIM_PARAM_UPDATE_DELTA_TIME | SIM_PARAM_UPDATE_NUM_SOLVER_ITERATIONS;