Remove mjTIMER_ACCELERATION, add mjTIMER_ADVANCE.

- mjTIMER_ACCELERATION is not very useful, it's usually very tiny (0.5% for humanoid, 1% for 22humanoids). It basically times a single call to `mj_solveM`.

- Added `mjTIMER_ADVANCE` to time `mj_Euler` and `mj_implicit` (which can be significant).

- Moved `mj_transmission` to `mjTIMER_KINEMATICS` where it belongs (and used to be).

PiperOrigin-RevId: 565936880
Change-Id: I26b8a067133594e5500ca1c809beb3518b4a8d9c

doc/includes/references.h

@@ -61,8 +61,8 @@ typedef enum mjtTimer_ {     // internal timers
   mjTIMER_POSITION,          // fwdPosition
   mjTIMER_VELOCITY,          // fwdVelocity
   mjTIMER_ACTUATION,         // fwdActuation
-  mjTIMER_ACCELERATION,      // fwdAcceleration
   mjTIMER_CONSTRAINT,        // fwdConstraint
+  mjTIMER_ADVANCE,           // mj_Euler, mj_implicit
 
   // breakdown of fwdPosition
   mjTIMER_POS_KINEMATICS,    // kinematics, com, tendon, transmission

include/mujoco/mjdata.h

@@ -72,8 +72,8 @@ typedef enum mjtTimer_ {     // internal timers
   mjTIMER_POSITION,          // fwdPosition
   mjTIMER_VELOCITY,          // fwdVelocity
   mjTIMER_ACTUATION,         // fwdActuation
-  mjTIMER_ACCELERATION,      // fwdAcceleration
   mjTIMER_CONSTRAINT,        // fwdConstraint
+  mjTIMER_ADVANCE,           // mj_Euler, mj_implicit
 
   // breakdown of fwdPosition
   mjTIMER_POS_KINEMATICS,    // kinematics, com, tendon, transmission

introspect/enums.py

@@ -431,8 +431,8 @@ ENUMS: Mapping[str, EnumDecl] = dict([
              ('mjTIMER_POSITION', 3),
              ('mjTIMER_VELOCITY', 4),
              ('mjTIMER_ACTUATION', 5),
-             ('mjTIMER_ACCELERATION', 6),
-             ('mjTIMER_CONSTRAINT', 7),
+             ('mjTIMER_CONSTRAINT', 6),
+             ('mjTIMER_ADVANCE', 7),
              ('mjTIMER_POS_KINEMATICS', 8),
              ('mjTIMER_POS_INERTIA', 9),
              ('mjTIMER_POS_COLLISION', 10),

sample/testspeed.cc

@@ -239,7 +239,7 @@ int main(int argc, char** argv) {
 
         // save step time, add up timing of components
         if (i == 0) total = istep;
-        if (i >= mjTIMER_POSITION && i <= mjTIMER_CONSTRAINT) {
+        if (i >= mjTIMER_POSITION && i <= mjTIMER_ADVANCE) {
           components += istep;
         }
       }

src/engine/engine_forward.c

@@ -118,9 +118,12 @@ void mj_fwdPosition(const mjModel* m, mjData* d) {
   if (mjENABLED(mjENBL_ISLAND)) {
     mj_island(m, d);
   }
-  mj_transmission(m, d);
   TM_END(mjTIMER_POS_MAKE);
 
+  TM_RESTART;
+  mj_transmission(m, d);
+  TM_END(mjTIMER_POS_KINEMATICS);
+
   TM_RESTART;
   mj_projectConstraint(m, d);
   TM_END(mjTIMER_POS_PROJECT);
@@ -400,7 +403,6 @@ void mj_fwdActuation(const mjModel* m, mjData* d) {
 
 // add up all non-constraint forces, compute qacc_smooth
 void mj_fwdAcceleration(const mjModel* m, mjData* d) {
-  TM_START;
   mj_markStack(d);
   int nv = m->nv;
 
@@ -414,7 +416,6 @@ void mj_fwdAcceleration(const mjModel* m, mjData* d) {
   mj_solveM(m, d, d->qacc_smooth, d->qfrc_smooth, 1);
 
   mj_freeStack(d);
-  TM_END(mjTIMER_ACCELERATION);
 }
 
 
@@ -609,6 +610,7 @@ static void mj_advance(const mjModel* m, mjData* d,
 
 // Euler integrator, semi-implicit in velocity, possibly skipping factorisation
 void mj_EulerSkip(const mjModel* m, mjData* d, int skipfactor) {
+  TM_START;
   int nv = m->nv, nM = m->nM;
   mj_markStack(d);
   mjtNum* qfrc = mj_stackAllocNum(d, nv);
@@ -655,6 +657,8 @@ void mj_EulerSkip(const mjModel* m, mjData* d, int skipfactor) {
   mj_advance(m, d, d->act_dot, qacc, NULL);
 
   mj_freeStack(d);
+
+  TM_END(mjTIMER_ADVANCE);
 }
 
 
@@ -774,6 +778,7 @@ void mj_RungeKutta(const mjModel* m, mjData* d, int N) {
 
 // fully implicit in velocity, possibly skipping factorization
 void mj_implicitSkip(const mjModel* m, mjData* d, int skipfactor) {
+  TM_START;
   int nv = m->nv;
 
   mj_markStack(d);
@@ -832,6 +837,8 @@ void mj_implicitSkip(const mjModel* m, mjData* d, int skipfactor) {
   mj_advance(m, d, d->act_dot, qacc, NULL);
 
   mj_freeStack(d);
+
+  TM_END(mjTIMER_ADVANCE);
 }
 
 

src/engine/engine_support.c

@@ -82,8 +82,8 @@ const char* mjTIMERSTRING[mjNTIMER]= {
   "position",
   "velocity",
   "actuation",
-  "acceleration",
   "constraint",
+  "advance",
   "pos_kinematics",
   "pos_inertia",
   "pos_collision",

unity/Runtime/Bindings/MjBindings.cs

@@ -129,8 +129,8 @@ public enum mjtTimer : int{
   mjTIMER_POSITION = 3,
   mjTIMER_VELOCITY = 4,
   mjTIMER_ACTUATION = 5,
-  mjTIMER_ACCELERATION = 6,
-  mjTIMER_CONSTRAINT = 7,
+  mjTIMER_CONSTRAINT = 6,
+  mjTIMER_ADVANCE = 7,
   mjTIMER_POS_KINEMATICS = 8,
   mjTIMER_POS_INERTIA = 9,
   mjTIMER_POS_COLLISION = 10,