[Bf-blender-cvs] [43ddf0e9a7f] master: Getting rid of OMP: first usage of new parallel BMesh items iteration instead.
Bastien Montagne
noreply at git.blender.org
Thu Nov 23 21:36:15 CET 2017
Commit: 43ddf0e9a7f0f9986ed24e05df0ce7eac5f944b6
Author: Bastien Montagne
Date: Thu Nov 23 21:21:32 2017 +0100
Branches: master
https://developer.blender.org/rB43ddf0e9a7f0f9986ed24e05df0ce7eac5f944b6
Getting rid of OMP: first usage of new parallel BMesh items iteration instead.
`BM_mesh_normals_update` was converted from OMP to new parallel iterator code,
basic test with heavily subdivided cube (24.5k faces) gives:
- old OMP code: average 10ms per run.
- new BLI_task code: average 6ms per run.
So new code seems to be easily 40% quicker, in addition to getting rid of OMP. ;)
Reviewers: sergey, campbellbarton
Differential Revision: https://developer.blender.org/D2930
===================================================================
M source/blender/bmesh/CMakeLists.txt
M source/blender/bmesh/intern/bmesh_mesh.c
===================================================================
diff --git a/source/blender/bmesh/CMakeLists.txt b/source/blender/bmesh/CMakeLists.txt
index ea24da86626..43e45eab98f 100644
--- a/source/blender/bmesh/CMakeLists.txt
+++ b/source/blender/bmesh/CMakeLists.txt
@@ -30,6 +30,7 @@ set(INC
../blentranslation
../makesdna
../../../intern/guardedalloc
+ ../../../intern/atomic
../../../intern/eigen
../../../extern/rangetree
)
diff --git a/source/blender/bmesh/intern/bmesh_mesh.c b/source/blender/bmesh/intern/bmesh_mesh.c
index 2ff670c770e..8407dc36040 100644
--- a/source/blender/bmesh/intern/bmesh_mesh.c
+++ b/source/blender/bmesh/intern/bmesh_mesh.c
@@ -35,6 +35,7 @@
#include "BLI_listbase.h"
#include "BLI_math.h"
#include "BLI_stack.h"
+#include "BLI_task.h"
#include "BLI_utildefines.h"
#include "BKE_cdderivedmesh.h"
@@ -42,6 +43,8 @@
#include "BKE_mesh.h"
#include "BKE_multires.h"
+#include "atomic_ops.h"
+
#include "intern/bmesh_private.h"
/* used as an extern, defined in bmesh.h */
@@ -318,146 +321,202 @@ void BM_mesh_free(BMesh *bm)
MEM_freeN(bm);
}
+
/**
* Helpers for #BM_mesh_normals_update and #BM_verts_calc_normal_vcos
*/
-static void bm_mesh_edges_calc_vectors(BMesh *bm, float (*edgevec)[3], const float (*vcos)[3])
+
+typedef struct BMEdgesCalcVectorsData {
+ /* Read-only data. */
+ const float (*vcos)[3];
+
+ /* Read-write data, but no need to protect it, no concurrency to fear here. */
+ float (*edgevec)[3];
+} BMEdgesCalcVectorsData;
+
+
+static void mesh_edges_calc_vectors_cb(void *userdata, MempoolIterData *mp_e)
{
- BMIter eiter;
- BMEdge *e;
- int index;
+ BMEdgesCalcVectorsData *data = userdata;
+ BMEdge *e = (BMEdge *)mp_e;
- if (vcos) {
- BM_mesh_elem_index_ensure(bm, BM_VERT);
+ if (e->l) {
+ const float *v1_co = data->vcos ? data->vcos[BM_elem_index_get(e->v1)] : e->v1->co;
+ const float *v2_co = data->vcos ? data->vcos[BM_elem_index_get(e->v2)] : e->v2->co;
+ sub_v3_v3v3(data->edgevec[BM_elem_index_get(e)], v2_co, v1_co);
+ normalize_v3(data->edgevec[BM_elem_index_get(e)]);
}
+ else {
+ /* the edge vector will not be needed when the edge has no radial */
+ }
+}
- BM_ITER_MESH_INDEX (e, &eiter, bm, BM_EDGES_OF_MESH, index) {
- BM_elem_index_set(e, index); /* set_inline */
+static void bm_mesh_edges_calc_vectors(BMesh *bm, float (*edgevec)[3], const float (*vcos)[3])
+{
+ BM_mesh_elem_index_ensure(bm, BM_EDGE | (vcos ? BM_VERT : 0));
- if (e->l) {
- const float *v1_co = vcos ? vcos[BM_elem_index_get(e->v1)] : e->v1->co;
- const float *v2_co = vcos ? vcos[BM_elem_index_get(e->v2)] : e->v2->co;
- sub_v3_v3v3(edgevec[index], v2_co, v1_co);
- normalize_v3(edgevec[index]);
- }
- else {
- /* the edge vector will not be needed when the edge has no radial */
+ BMEdgesCalcVectorsData data = {
+ .vcos = vcos,
+ .edgevec = edgevec
+ };
+
+ BM_iter_parallel(bm, BM_EDGES_OF_MESH, mesh_edges_calc_vectors_cb, &data, bm->totedge >= BM_OMP_LIMIT);
+}
+
+
+typedef struct BMVertsCalcNormalsData {
+ /* Read-only data. */
+ const float (*fnos)[3];
+ const float (*edgevec)[3];
+ const float (*vcos)[3];
+
+ /* Read-write data, protected by an atomic-based fake spinlock-like system... */
+ float (*vnos)[3];
+} BMVertsCalcNormalsData;
+
+static void mesh_verts_calc_normals_accum_cb(void *userdata, MempoolIterData *mp_f)
+{
+ BMVertsCalcNormalsData *data = userdata;
+ BMFace *f = (BMFace *)mp_f;
+
+ const float *f_no = data->fnos ? data->fnos[BM_elem_index_get(f)] : f->no;
+
+ BMLoop *l_first, *l_iter;
+ l_iter = l_first = BM_FACE_FIRST_LOOP(f);
+ do {
+ const float *e1diff, *e2diff;
+ float dotprod;
+ float fac;
+
+ /* calculate the dot product of the two edges that
+ * meet at the loop's vertex */
+ e1diff = data->edgevec[BM_elem_index_get(l_iter->prev->e)];
+ e2diff = data->edgevec[BM_elem_index_get(l_iter->e)];
+ dotprod = dot_v3v3(e1diff, e2diff);
+
+ /* edge vectors are calculated from e->v1 to e->v2, so
+ * adjust the dot product if one but not both loops
+ * actually runs from from e->v2 to e->v1 */
+ if ((l_iter->prev->e->v1 == l_iter->prev->v) ^ (l_iter->e->v1 == l_iter->v)) {
+ dotprod = -dotprod;
+ }
+
+ fac = saacos(-dotprod);
+
+ /* accumulate weighted face normal into the vertex's normal */
+ float *v_no = data->vnos ? data->vnos[BM_elem_index_get(l_iter->v)] : l_iter->v->no;
+
+ /* This block is a lockless threadsafe madd_v3_v3fl.
+ * It uses the first float of the vector as a sort of cheap spinlock,
+ * assuming FLT_MAX is a safe 'illegal' value that cannot be set here otherwise.
+ * It also assumes that collisions between threads are highly unlikely,
+ * else performances would be quite bad here. */
+ float virtual_lock = v_no[0];
+ while ((virtual_lock = atomic_cas_float(&v_no[0], virtual_lock, FLT_MAX)) == FLT_MAX) {
+ /* This loops until following conditions are met:
+ * - v_no[0] has same value as virtual_lock (i.e. it did not change since last try).
+ * - v_no_[0] was not FLT_MAX, i.e. it was not locked by another thread.
+ */
}
+ /* Now we own that normal value, and can change it.
+ * But first scalar of the vector must not be changed yet, it's our lock! */
+ virtual_lock += f_no[0] * fac;
+ v_no[1] += f_no[1] * fac;
+ v_no[2] += f_no[2] * fac;
+ /* Second atomic operation to 'release' our lock on that vector and set its first scalar value. */
+ virtual_lock = atomic_cas_float(&v_no[0], FLT_MAX, virtual_lock);
+ BLI_assert(virtual_lock == FLT_MAX);
+
+ } while ((l_iter = l_iter->next) != l_first);
+}
+
+static void mesh_verts_calc_normals_normalize_cb(void *userdata, MempoolIterData *mp_v)
+{
+ BMVertsCalcNormalsData *data = userdata;
+ BMVert *v = (BMVert *)mp_v;
+
+ float *v_no = data->vnos ? data->vnos[BM_elem_index_get(v)] : v->no;
+ if (UNLIKELY(normalize_v3(v_no) == 0.0f)) {
+ const float *v_co = data->vcos ? data->vcos[BM_elem_index_get(v)] : v->co;
+ normalize_v3_v3(v_no, v_co);
}
- bm->elem_index_dirty &= ~BM_EDGE;
}
static void bm_mesh_verts_calc_normals(
BMesh *bm, const float (*edgevec)[3], const float (*fnos)[3],
const float (*vcos)[3], float (*vnos)[3])
{
- BM_mesh_elem_index_ensure(bm, (vnos) ? (BM_EDGE | BM_VERT) : BM_EDGE);
+ BM_mesh_elem_index_ensure(bm, (BM_EDGE | BM_FACE) | ((vnos || vcos) ? BM_VERT : 0));
- /* add weighted face normals to vertices */
- {
- BMIter fiter;
- BMFace *f;
- int i;
-
- BM_ITER_MESH_INDEX (f, &fiter, bm, BM_FACES_OF_MESH, i) {
- BMLoop *l_first, *l_iter;
- const float *f_no = fnos ? fnos[i] : f->no;
-
- l_iter = l_first = BM_FACE_FIRST_LOOP(f);
- do {
- const float *e1diff, *e2diff;
- float dotprod;
- float fac;
- float *v_no = vnos ? vnos[BM_elem_index_get(l_iter->v)] : l_iter->v->no;
-
- /* calculate the dot product of the two edges that
- * meet at the loop's vertex */
- e1diff = edgevec[BM_elem_index_get(l_iter->prev->e)];
- e2diff = edgevec[BM_elem_index_get(l_iter->e)];
- dotprod = dot_v3v3(e1diff, e2diff);
-
- /* edge vectors are calculated from e->v1 to e->v2, so
- * adjust the dot product if one but not both loops
- * actually runs from from e->v2 to e->v1 */
- if ((l_iter->prev->e->v1 == l_iter->prev->v) ^ (l_iter->e->v1 == l_iter->v)) {
- dotprod = -dotprod;
- }
+ BMVertsCalcNormalsData data = {
+ .fnos = fnos,
+ .edgevec = edgevec,
+ .vcos = vcos,
+ .vnos = vnos
+ };
- fac = saacos(-dotprod);
+ BM_iter_parallel(bm, BM_FACES_OF_MESH, mesh_verts_calc_normals_accum_cb, &data, bm->totface >= BM_OMP_LIMIT);
- /* accumulate weighted face normal into the vertex's normal */
- madd_v3_v3fl(v_no, f_no, fac);
- } while ((l_iter = l_iter->next) != l_first);
- }
- }
+ /* normalize the accumulated vertex normals */
+ BM_iter_parallel(bm, BM_VERTS_OF_MESH, mesh_verts_calc_normals_normalize_cb, &data, bm->totvert >= BM_OMP_LIMIT);
+}
- /* normalize the accumulated vertex normals */
- {
- BMIter viter;
- BMVert *v;
- int i;
-
- BM_ITER_MESH_INDEX (v, &viter, bm, BM_VERTS_OF_MESH, i) {
- float *v_no = vnos ? vnos[i] : v->no;
- if (UNLIKELY(normalize_v3(v_no) == 0.0f)) {
- const float *v_co = vcos ? vcos[i] : v->co;
- normalize_v3_v3(v_no, v_co);
- }
- }
- }
+static void mesh_faces_calc_normals_cb(void *UNUSED(userdata), MempoolIterData *mp_f)
+{
+ BMFace *f = (BMFace *)mp_f;
+
+ BM_face_normal_update(f);
}
+
/**
* \brief BMesh Compute Normals
*
* Updates the normals of a mesh.
*/
+#include "PIL_time_utildefines.h"
void BM_mesh_normals_update(BMesh *bm)
{
float (*edgevec)[3] = MEM_mallocN(sizeof(*edgevec) * bm->totedge, __func__);
-#pragma omp parallel sections if (bm->totvert + bm->totedge + bm->totface >= BM_OMP_LIMIT)
- {
-#pragma omp section
- {
- /* calculate all face normals */
- BMIter fiter;
- BMFace *f;
- int i;
-
- BM_ITER_MESH_INDEX (f, &fiter, bm, BM_FACES_OF_MESH, i) {
- BM_elem_index_set(f, i); /* set_inline */
- BM_face_normal_update(f);
- }
- bm->elem_index_dirty &= ~BM_FACE;
- }
-#pragma omp section
- {
- /* Zero out vertex normals */
- BMIter viter;
- BMVert *v;
- int i;
-
- BM_ITER_MESH_INDEX (v, &viter, bm, BM_VERTS_OF_MESH, i) {
- BM_elem_index_set(v, i); /* set_inline */
- zero_v3(v->no);
- }
- bm->elem_index_dirty &= ~BM_VERT;
- }
-#pragma omp section
- {
- /* Compute normalized direction vectors for each edge.
- * Directions will be used for calculating the weights of the face normals on the vertex normals.
- */
- bm_mesh_edges_calc_vectors(bm, edgevec, NULL);
- }
+ TIMEIT_START_AVERAGED(bmesh_nors);
+
+ /* Parallel mempool iteration does not allow to generate indices inline anymore... */
+ BM_mesh_elem_index_ensure(bm, (BM_EDGE | BM_FACE));
+
+ /* calculate all face normals */
+ TIMEIT_START_AVERAGED(faces_nors);
+ BM_iter_parallel(bm, BM_FACES_OF_MESH, mesh_faces_calc_normals_cb, NULL, bm->totface >= BM_OMP_LIMIT);
+ TIMEIT_END_AVERAGED(faces_nors);
+
+ /* Zero out vertex normals */
+ BMIter viter;
+ BMVert *v;
+ int i;
+
+ TIMEIT_START_AVERAGED(verts_zero_nors);
+ BM_ITER_MESH_INDEX (v, &viter, bm, BM_VERTS_OF_MESH, i) {
+ BM_elem_index_set(v, i); /* set_inline */
+ zero_v3(v->no);
}
- /* end omp */
+ bm->elem_index_dirty &= ~BM_VERT;
+ TIMEIT_END_AVERAGED(verts_zero_no
@@ Diff output truncated at 10240 characters. @@
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