Only use atomic operations when SWIFT_TASKS_WITHOUT_ATOMICS is not defined

src/gravity/MultiSoftening/gravity.h

@@ -78,7 +78,11 @@ __attribute__((always_inline)) INLINE static float gravity_get_softening(
 __attribute__((always_inline)) INLINE static void
 gravity_add_comoving_potential(struct gpart* restrict gp, float pot) {
 
+#ifdef SWIFT_TASKS_WITHOUT_ATOMICS
+  gp->potential += pot;
+#else
   atomic_add_f(&gp->potential, pot);
+#endif
 }
 
 /**

src/gravity/Potential/gravity.h

@@ -64,7 +64,11 @@ __attribute__((always_inline)) INLINE static float gravity_get_softening(
 __attribute__((always_inline)) INLINE static void
 gravity_add_comoving_potential(struct gpart* restrict gp, float pot) {
 
+#ifdef SWIFT_TASKS_WITHOUT_ATOMICS
+  gp->potential += pot;
+#else
   atomic_add_f(&gp->potential, pot);
+#endif
 }
 
 /**

src/gravity_cache.h

@@ -491,9 +491,15 @@ __attribute__((always_inline)) INLINE static void gravity_cache_write_back(
   /* Write stuff back to the particles */
   for (int i = 0; i < gcount; ++i) {
     if (active[i]) {
+#ifdef SWIFT_TASKS_WITHOUT_ATOMICS
+      gparts[i].a_grav[0] += a_x[i];
+      gparts[i].a_grav[1] += a_y[i];
+      gparts[i].a_grav[2] += a_z[i];
+#else
       atomic_add_f(&gparts[i].a_grav[0], a_x[i]);
       atomic_add_f(&gparts[i].a_grav[1], a_y[i]);
       atomic_add_f(&gparts[i].a_grav[2], a_z[i]);
+#endif
       gravity_add_comoving_potential(&gparts[i], pot[i]);
     }
   }

src/mesh_gravity.c

@@ -334,10 +334,16 @@ void mesh_to_gparts_CIC(struct gpart* gp, const double* pot, const int N,
   /* ---- */
 
   /* Store things back */
-  gravity_add_comoving_potential(gp, p);
+#ifdef SWIFT_TASKS_WITHOUT_ATOMICS
+  gp->a_grav[0] += fac * a[0];
+  gp->a_grav[1] += fac * a[1];
+  gp->a_grav[2] += fac * a[2];
+#else
   atomic_add_f(&gp->a_grav[0], fac * a[0]);
   atomic_add_f(&gp->a_grav[1], fac * a[1]);
   atomic_add_f(&gp->a_grav[2], fac * a[2]);
+#endif
+  gravity_add_comoving_potential(gp, p);
 #ifdef SWIFT_GRAVITY_FORCE_CHECKS
   gp->potential_PM = p;
   gp->a_grav_PM[0] = fac * a[0];

src/multipole.h

@@ -2589,9 +2589,15 @@ INLINE static void gravity_L2P(const struct grav_tensor *lb,
 #endif
 
   /* Update the particle */
+#ifdef SWIFT_TASKS_WITHOUT_ATOMICS
+  gp->a_grav[0] += a_grav[0];
+  gp->a_grav[1] += a_grav[1];
+  gp->a_grav[2] += a_grav[2];
+#else
   atomic_add_f(&gp->a_grav[0], a_grav[0]);
   atomic_add_f(&gp->a_grav[1], a_grav[1]);
   atomic_add_f(&gp->a_grav[2], a_grav[2]);
+#endif
   gravity_add_comoving_potential(gp, pot);
 
 #ifdef SWIFT_GRAVITY_FORCE_CHECKS

src/runner_doiact_grav.c

@@ -1359,6 +1359,7 @@ static INLINE void runner_dopair_grav_mm_symmetric(struct runner *r,
         cj->grav.ti_old_multipole, cj->nodeID, ci->nodeID, e->ti_current);
 #endif
 
+#ifndef SWIFT_TASKS_WITHOUT_ATOMICS
   /* Lock the multipoles
    * Note we impose a hierarchy to solve the dining philosopher problem */
   if (ci < cj) {
@@ -1368,15 +1369,18 @@ static INLINE void runner_dopair_grav_mm_symmetric(struct runner *r,
     lock_lock(&cj->grav.mlock);
     lock_lock(&ci->grav.mlock);
   }
+#endif
 
   /* Let's interact at this level */
   gravity_M2L_symmetric(&ci->grav.multipole->pot, &cj->grav.multipole->pot,
                         multi_i, multi_j, ci->grav.multipole->CoM,
                         cj->grav.multipole->CoM, props, periodic, dim, r_s_inv);
 
+#ifndef SWIFT_TASKS_WITHOUT_ATOMICS
   /* Unlock the multipoles */
   if (lock_unlock(&ci->grav.mlock) != 0) error("Failed to unlock multipole");
   if (lock_unlock(&cj->grav.mlock) != 0) error("Failed to unlock multipole");
+#endif
 
   TIMER_TOC(timer_dopair_grav_mm);
 }
@@ -1424,6 +1428,7 @@ static INLINE void runner_dopair_grav_mm_nonsym(struct runner *r,
         cj->grav.ti_old_multipole, cj->nodeID, ci->nodeID, e->ti_current);
 #endif
 
+#ifndef SWIFT_TASKS_WITHOUT_ATOMICS
   /* Lock the multipoles
    * Note we impose a hierarchy to solve the dining philosopher problem */
   if (ci < cj) {
@@ -1433,14 +1438,17 @@ static INLINE void runner_dopair_grav_mm_nonsym(struct runner *r,
     lock_lock(&cj->grav.mlock);
     lock_lock(&ci->grav.mlock);
   }
+#endif
 
   /* Let's interact at this level */
   gravity_M2L_nonsym(&ci->grav.multipole->pot, multi_j, ci->grav.multipole->CoM,
                      cj->grav.multipole->CoM, props, periodic, dim, r_s_inv);
 
+#ifndef SWIFT_TASKS_WITHOUT_ATOMICS
   /* Unlock the multipoles */
   if (lock_unlock(&ci->grav.mlock) != 0) error("Failed to unlock multipole");
   if (lock_unlock(&cj->grav.mlock) != 0) error("Failed to unlock multipole");
+#endif
 
   TIMER_TOC(timer_dopair_grav_mm);
 }

src/timestep_limiter_iact.h

@@ -87,8 +87,12 @@ __attribute__((always_inline)) INLINE static void runner_iact_nonsym_limiter(
   /* Wake up the neighbour? */
   if (pj->time_bin > pi->time_bin + time_bin_neighbour_max_delta_bin) {
 
-    /* Store the smallest time bin that woke up this particle */
+  /* Store the smallest time bin that woke up this particle */
+#ifdef SWIFT_TASKS_WITHOUT_ATOMICS
+    pj->limiter_data.wakeup = max(pj->limiter_data.wakeup, -pi->time_bin);
+#else
     atomic_max_c(&pj->limiter_data.wakeup, -pi->time_bin);
+#endif
   }
 }