Bad perfomance

[whiplash]

Hello!

I have a question about better perfomance of Bullet. My simple scene (i use Ogre):
1) static plane - btStaticPlaneShape;
2) one static building (consist is five inner rooms) - btTriangleMesh -> btBvhTriangleMeshShape;
3) one dynamic (moving manually "character") object - btMultiSphereShape (one element).

If i moving dynamic character near outer wall of room - i have 120 fps. But if i moving character to room (near inner wall of room) - fps down to 20-30 fps. Why? Building have not many polygons - 400/500.

Whether there is other path of increase in perfomance, except approximating to a box/sphere/...?

[Dirk Gregorius]

You can use Bullet's internal profiler to dump all samples. Maybe just dump at the two scenarios and post the results here. I am sure Erwin can help you to isolate the bottleneck.

[whiplash]

Profiler log:

Code: Select all

Profiling: Root (total running time: 351.813 ms) ---
0 -- stepSimulation (99.99 %) :: 351.768 ms / frame (1 calls)
Unaccounted: (0.013 %) :: 0.045 ms
...----------------------------------
...Profiling: stepSimulation (total running time: 351.768 ms) ---
...0 -- synchronizeMotionStates (0.06 %) :: 0.196 ms / frame (10 calls)
...1 -- internalSingleStepSimulation (99.93 %) :: 351.516 ms / frame (10 calls)
...Unaccounted: (0.016 %) :: 0.056 ms
......----------------------------------
......Profiling: internalSingleStepSimulation (total running time: 351.516 ms) ---
......0 -- updateActivationState (0.01 %) :: 0.034 ms / frame (10 calls)
......1 -- updateActions (0.01 %) :: 0.018 ms / frame (10 calls)
......2 -- integrateTransforms (0.09 %) :: 0.333 ms / frame (10 calls)
......3 -- solveConstraints (3.71 %) :: 13.058 ms / frame (10 calls)
......4 -- calculateSimulationIslands (0.03 %) :: 0.121 ms / frame (10 calls)
......5 -- performDiscreteCollisionDetection (95.86 %) :: 336.951 ms / frame (10 calls)
......6 -- predictUnconstraintMotion (0.23 %) :: 0.802 ms / frame (10 calls)
......Unaccounted: (0.057 %) :: 0.199 ms
.........----------------------------------
.........Profiling: solveConstraints (total running time: 13.058 ms) ---
.........0 -- solveGroup (91.41 %) :: 11.936 ms / frame (10 calls)
.........1 -- processIslands (5.02 %) :: 0.656 ms / frame (10 calls)
.........2 -- islandUnionFindAndQuickSort (1.24 %) :: 0.162 ms / frame (10 calls)
.........Unaccounted: (2.328 %) :: 0.304 ms
............----------------------------------
............Profiling: solveGroup (total running time: 11.936 ms) ---
............0 -- solveGroupCacheFriendlyIterations (50.43 %) :: 6.019 ms / frame (10 calls)
............1 -- solveGroupCacheFriendlySetup (48.40 %) :: 5.777 ms / frame (10 calls)
............Unaccounted: (1.173 %) :: 0.140 ms
.........----------------------------------
.........Profiling: performDiscreteCollisionDetection (total running time: 336.951 ms) ---
.........0 -- dispatchAllCollisionPairs (99.88 %) :: 336.539 ms / frame (10 calls)
.........1 -- calculateOverlappingPairs (0.01 %) :: 0.029 ms / frame (10 calls)
.........2 -- updateAabbs (0.09 %) :: 0.296 ms / frame (10 calls)
.........Unaccounted: (0.026 %) :: 0.087 ms

[Dirk Gregorius]

Are you using a release build?

[whiplash]

No, i using debug build. But release build not better:

Code: Select all

Profiling: Root (total running time: 347.264 ms) ---
0 -- stepSimulation (99.99 %) :: 347.217 ms / frame (1 calls)
Unaccounted: (0.014 %) :: 0.047 ms
...----------------------------------
...Profiling: stepSimulation (total running time: 347.217 ms) ---
...0 -- synchronizeMotionStates (0.06 %) :: 0.200 ms / frame (10 calls)
...1 -- internalSingleStepSimulation (99.93 %) :: 346.966 ms / frame (10 calls)
...Unaccounted: (0.015 %) :: 0.051 ms
......----------------------------------
......Profiling: internalSingleStepSimulation (total running time: 346.966 ms) ---
......0 -- updateActivationState (0.01 %) :: 0.034 ms / frame (10 calls)
......1 -- updateActions (0.00 %) :: 0.017 ms / frame (10 calls)
......2 -- integrateTransforms (0.11 %) :: 0.369 ms / frame (10 calls)
......3 -- solveConstraints (3.49 %) :: 12.124 ms / frame (10 calls)
......4 -- calculateSimulationIslands (0.03 %) :: 0.119 ms / frame (10 calls)
......5 -- performDiscreteCollisionDetection (96.25 %) :: 333.941 ms / frame (10 calls)
......6 -- predictUnconstraintMotion (0.05 %) :: 0.167 ms / frame (10 calls)
......Unaccounted: (0.056 %) :: 0.195 ms
.........----------------------------------
.........Profiling: solveConstraints (total running time: 12.124 ms) ---
.........0 -- solveGroup (90.45 %) :: 10.966 ms / frame (10 calls)
.........1 -- processIslands (5.94 %) :: 0.720 ms / frame (10 calls)
.........2 -- islandUnionFindAndQuickSort (1.34 %) :: 0.162 ms / frame (10 calls)
.........Unaccounted: (2.276 %) :: 0.276 ms
............----------------------------------
............Profiling: solveGroup (total running time: 10.966 ms) ---
............0 -- solveGroupCacheFriendlyIterations (46.25 %) :: 5.072 ms / frame (10 calls)
............1 -- solveGroupCacheFriendlySetup (52.54 %) :: 5.762 ms / frame (10 calls)
............Unaccounted: (1.204 %) :: 0.132 ms
.........----------------------------------
.........Profiling: performDiscreteCollisionDetection (total running time: 333.941 ms) ---
.........0 -- dispatchAllCollisionPairs (99.89 %) :: 333.572 ms / frame (10 calls)
.........1 -- calculateOverlappingPairs (0.01 %) :: 0.026 ms / frame (10 calls)
.........2 -- updateAabbs (0.08 %) :: 0.259 ms / frame (10 calls)
.........Unaccounted: (0.025 %) :: 0.084 ms

[Dirk Gregorius]

You should not profile debug builds!

This doesn't make sense! Are you sure you are linking the release build of Bullet. It is not enough to simply change the build type in your application.

HTH,
-Dirk

[whiplash]

I use preprocessor's commands:

Code: Select all

#ifdef _DEBUG
	#pragma comment(lib, "bulletdynamics_d.lib")
	#pragma comment(lib, "bulletcollision_d.lib")
	#pragma comment(lib, "linearmath_d.lib")
#else
	#pragma comment(lib, "bulletdynamics.lib")
	#pragma comment(lib, "bulletcollision.lib")
	#pragma comment(lib, "linearmath.lib")
#endif

(*.lib in catalogs "...\lib\Debug" and "...\lib\Release")

My link aren't correct?