Remove thread-synchronization from arrays, which was way too slow, and

only really needed for dmnsn_progress anyway.

5 files changed, 102 insertions, 146 deletions

diff --git a/libdimension/array.c b/libdimension/array.c
index 82588aa..a22b450 100644
--- a/libdimension/array.c
+++ b/libdimension/array.c
@@ -22,10 +22,6 @@
 #include <pthread.h>
 #include <string.h> /* For memcpy */
 
-/* The raw implementations, which don't do any thread synchronicity */
-static void dmnsn_array_get_impl(const dmnsn_array *array, size_t i, void *obj);
-static void dmnsn_array_set_impl(dmnsn_array *array, size_t i, const void *obj);
-
 /* Allocate a new array - guaranteed not to fail if it returns */
 dmnsn_array *
 dmnsn_new_array(size_t obj_size)
@@ -41,12 +37,6 @@ dmnsn_new_array(size_t obj_size)
     if (!array->ptr) {
       dmnsn_error(DMNSN_SEVERITY_HIGH, "Array allocation failed.");
     }
-
-    /* Allocate the read-write lock */
-    array->rwlock = malloc(sizeof(pthread_rwlock_t));
-    if (!array->rwlock || pthread_rwlock_init(array->rwlock, NULL) != 0) {
-      dmnsn_error(DMNSN_SEVERITY_HIGH, "Array rwlock allocation failed.");
-    }
   }
 
   return array;
@@ -55,98 +45,70 @@ dmnsn_new_array(size_t obj_size)
 /* Delete the array */
 void dmnsn_delete_array(dmnsn_array *array) {
   if (array) {
-    if (pthread_rwlock_destroy(array->rwlock) != 0) {
-      dmnsn_error(DMNSN_SEVERITY_LOW, "Leaking rwlock in array deallocation.");
-    }
-
-    free(array->rwlock);
     free(array->ptr);
     free(array);
   }
 }
 
-/* Push obj to the end of the array, atomically */
+/* Push obj to the end of the array */
 void
 dmnsn_array_push(dmnsn_array *array, const void *obj)
 {
-  dmnsn_array_wrlock(array);
-    dmnsn_array_set_impl(array, dmnsn_array_size_unlocked(array), obj);
-  dmnsn_array_unlock(array);
+  dmnsn_array_set(array, dmnsn_array_size(array), obj);
 }
 
-/* Pop obj from the end of the array, atomically */
+/* Pop obj from the end of the array */
 void
 dmnsn_array_pop(dmnsn_array *array, void *obj)
 {
-  size_t size;
-
-  dmnsn_array_wrlock(array);
-    size = dmnsn_array_size_unlocked(array);
-    dmnsn_array_get_impl(array, size - 1, obj);   /* Copy the object */
-    dmnsn_array_resize_unlocked(array, size - 1); /* Shrink the array */
-  dmnsn_array_unlock(array);
+  size_t size = dmnsn_array_size(array);
+  dmnsn_array_get(array, size - 1, obj); /* Copy the object */
+  dmnsn_array_resize(array, size - 1);   /* Shrink the array */
 }
 
 /* Get the i'th object, bailing out if i is out of range */
 void
 dmnsn_array_get(const dmnsn_array *array, size_t i, void *obj)
 {
-  dmnsn_array_rdlock(array);
-    dmnsn_array_get_impl(array, i, obj);
-  dmnsn_array_unlock(array);
+  if (i >= dmnsn_array_size(array)) {
+    /* Range check failed */
+    dmnsn_error(DMNSN_SEVERITY_HIGH, "Array index out of bounds.");
+  }
+  memcpy(obj, (char *)array->ptr + array->obj_size*i, array->obj_size);
 }
 
 /* Set the i'th object, expanding the array if necessary */
 void
 dmnsn_array_set(dmnsn_array *array, size_t i, const void *obj)
 {
-  dmnsn_array_wrlock(array);
-    dmnsn_array_set_impl(array, i, obj);
-  dmnsn_array_unlock(array);
-}
-
-/* Get the size of the array, atomically */
-size_t
-dmnsn_array_size(const dmnsn_array *array)
-{
-  size_t size;
-
-  dmnsn_array_rdlock(array);
-    size = dmnsn_array_size_unlocked(array);
-  dmnsn_array_unlock(array);
-
-  return size;
-}
-
-/* Set the size of the array, atomically */
-void
-dmnsn_array_resize(dmnsn_array *array, size_t length)
-{
-  dmnsn_array_wrlock(array);
-    dmnsn_array_resize_unlocked(array, length);
-  dmnsn_array_unlock(array);
+  if (i >= dmnsn_array_size(array)) {
+    /* Resize if i is out of range */
+    dmnsn_array_resize(array, i + 1);
+  }
+  memcpy((char *)array->ptr + array->obj_size*i, obj, array->obj_size);
 }
 
-/* Thread-unsafe range-checked element access */
+/* Element access */
 void *
 dmnsn_array_at(dmnsn_array *array, size_t i)
 {
-  if (i >= dmnsn_array_size_unlocked(array)) {
-    dmnsn_error(DMNSN_SEVERITY_HIGH, "Array index out of bounds.");
+  if (i >= dmnsn_array_size(array)) {
+    /* Resize if i is out of range */
+    dmnsn_array_resize(array, i + 1);
   }
   return (char *)array->ptr + array->obj_size*i;
 }
 
-/* Get the size non-atomically, for manual locking */
+/* Get the size of the array */
 size_t
-dmnsn_array_size_unlocked(const dmnsn_array *array)
+dmnsn_array_size(const dmnsn_array *array)
 {
   return array->length;
 }
 
-/* Set the size non-atomically, for manual locking */
+/* Set the size of the array, atomically */
 void
-dmnsn_array_resize_unlocked(dmnsn_array *array, size_t length)
+dmnsn_array_resize(dmnsn_array *array, size_t length)
 {
   if (length > array->capacity) {
     /* Resize if we don't have enough capacity */
@@ -159,60 +121,3 @@ dmnsn_array_resize_unlocked(dmnsn_array *array, size_t length)
 
   array->length = length;
 }
-
-/* Set a manual read-lock */
-void
-dmnsn_array_rdlock(const dmnsn_array *array)
-{
-  if (pthread_rwlock_rdlock(array->rwlock) != 0) {
-    /* Medium severity, because undefined behaviour is pretty likely if our
-       reads and writes aren't synced */
-    dmnsn_error(DMNSN_SEVERITY_MEDIUM,
-                "Couldn't acquire read-lock for array.");
-  }
-}
-
-/* Set a manual write-lock */
-void
-dmnsn_array_wrlock(dmnsn_array *array)
-{
-  if (pthread_rwlock_wrlock(array->rwlock) != 0) {
-    /* Medium severity, because undefined behaviour is pretty likely if our
-       reads and writes aren't synced */
-    dmnsn_error(DMNSN_SEVERITY_MEDIUM,
-                "Couldn't acquire write-lock for array.");
-  }
-}
-
-/* Unset a manual lock */
-void
-dmnsn_array_unlock(const dmnsn_array *array)
-{
-  if (pthread_rwlock_unlock(array->rwlock) != 0) {
-    /* Medium severity, because if the array is locked, we're likely to hang
-       the next time we try to read or write it */
-    dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't unlock array.");
-  }
-}
-
-/* Actual "get" implementation */
-static void
-dmnsn_array_get_impl(const dmnsn_array *array, size_t i, void *obj)
-{
-  if (i >= dmnsn_array_size_unlocked(array)) {
-    /* Range check failed */
-    dmnsn_error(DMNSN_SEVERITY_HIGH, "Array index out of bounds.");
-  }
-  memcpy(obj, array->ptr + array->obj_size*i, array->obj_size);
-}
-
-/* Actual "set" implementation */
-static void
-dmnsn_array_set_impl(dmnsn_array *array, size_t i, const void *obj)
-{
-  if (i >= dmnsn_array_size_unlocked(array)) {
-    /* Resize if i is out of range */
-    dmnsn_array_resize_unlocked(array, i + 1);
-  }
-  memcpy(array->ptr + array->obj_size*i, obj, array->obj_size);
-}
diff --git a/libdimension/dimension/array.h b/libdimension/dimension/array.h
index 1c8f601..5d5e50e 100644
--- a/libdimension/dimension/array.h
+++ b/libdimension/dimension/array.h
@@ -32,9 +32,6 @@
 typedef struct {
   void *ptr;
   size_t obj_size, length, capacity;
-
-  /* Synchronicity control (pointer so it's not const) */
-  pthread_rwlock_t *rwlock;
 } dmnsn_array;
 
 /* Array allocation never returns NULL - if dmnsn_new_array returns, it
@@ -42,24 +39,13 @@ typedef struct {
 dmnsn_array *dmnsn_new_array(size_t obj_size);
 void dmnsn_delete_array(dmnsn_array *array);
 
-/* Thread-safe atomic array access */
-
 void dmnsn_array_push(dmnsn_array *array, const void *obj);
 void dmnsn_array_pop(dmnsn_array *array, void *obj);
 void dmnsn_array_get(const dmnsn_array *array, size_t i, void *obj);
 void dmnsn_array_set(dmnsn_array *array, size_t i, const void *obj);
+void *dmnsn_array_at(dmnsn_array *array, size_t i);
 
 size_t dmnsn_array_size(const dmnsn_array *array);
 void   dmnsn_array_resize(dmnsn_array *array, size_t length);
 
-/* Non-atomic operations for manual locking */
-void *dmnsn_array_at(dmnsn_array *array, size_t i);
-size_t dmnsn_array_size_unlocked(const dmnsn_array *array);
-void dmnsn_array_resize_unlocked(dmnsn_array *array, size_t length);
-
-/* Manual locking */
-void dmnsn_array_rdlock(const dmnsn_array *array);
-void dmnsn_array_wrlock(dmnsn_array *array);
-void dmnsn_array_unlock(const dmnsn_array *array);
-
 #endif /* DIMENSION_ARRAY_H */
diff --git a/libdimension/dimension/progress.h b/libdimension/dimension/progress.h
index 7958ab9..57a38b6 100644
--- a/libdimension/dimension/progress.h
+++ b/libdimension/dimension/progress.h
@@ -44,6 +44,9 @@ typedef struct {
   /* The worker thread */
   pthread_t thread;
 
+  /* Read-write synchronization */
+  pthread_rwlock_t *rwlock;
+
   /* Condition variable for waiting for a particular amount of progress */
   pthread_cond_t  *cond;
   pthread_mutex_t *mutex;
diff --git a/libdimension/progress.c b/libdimension/progress.c
index f25af74..1f50e4c 100644
--- a/libdimension/progress.c
+++ b/libdimension/progress.c
@@ -22,6 +22,11 @@
 #include <pthread.h>
 #include <stdlib.h> /* For malloc */
 
+/* For thread synchronization */
+static void dmnsn_progress_rdlock(const dmnsn_progress *progress);
+static void dmnsn_progress_wrlock(dmnsn_progress *progress);
+static void dmnsn_progress_unlock(const dmnsn_progress *progress);
+
 /* Allocate a new dmnsn_progress*, returning NULL on failure */
 dmnsn_progress *
 dmnsn_new_progress()
@@ -32,10 +37,18 @@ dmnsn_new_progress()
     progress->elements = dmnsn_new_array(sizeof(dmnsn_progress_element));
     dmnsn_array_push(progress->elements, &element);
 
-    /* Allocate space for the condition variable and mutex */
+    /* Allocate space for the rwlock, condition variable, and mutex */
+
+    progress->rwlock = malloc(sizeof(pthread_rwlock_t));
+    if (!progress->rwlock) {
+      dmnsn_delete_array(progress->elements);
+      free(progress);
+      return NULL;
+    }
 
     progress->cond = malloc(sizeof(pthread_cond_t));
     if (!progress->cond) {
+      free(progress->rwlock);
       dmnsn_delete_array(progress->elements);
       free(progress);
       return NULL;
@@ -43,6 +56,16 @@ dmnsn_new_progress()
 
     progress->mutex = malloc(sizeof(pthread_mutex_t));
     if (!progress->mutex) {
+      free(progress->rwlock);
+      free(progress->cond);
+      dmnsn_delete_array(progress->elements);
+      free(progress);
+      return NULL;
+    }
+
+    if (pthread_rwlock_init(progress->rwlock, NULL) != 0) {
+      free(progress->rwlock);
+      free(progress->mutex);
       free(progress->cond);
       dmnsn_delete_array(progress->elements);
       free(progress);
@@ -50,6 +73,11 @@ dmnsn_new_progress()
     }
 
     if (pthread_cond_init(progress->cond, NULL) != 0) {
+      if (pthread_rwlock_destroy(progress->rwlock) != 0) {
+        dmnsn_error(DMNSN_SEVERITY_LOW,
+                    "Leaking rwlock in failed allocation.");
+      }
+      free(progress->rwlock);
       free(progress->mutex);
       free(progress->cond);
       dmnsn_delete_array(progress->elements);
@@ -57,10 +85,15 @@ dmnsn_new_progress()
       return NULL;
     }
     if (pthread_mutex_init(progress->mutex, NULL) != 0) {
+      if (pthread_rwlock_destroy(progress->rwlock) != 0) {
+        dmnsn_error(DMNSN_SEVERITY_LOW,
+                    "Leaking rwlock in failed allocation.");
+      }
       if (pthread_cond_destroy(progress->cond) != 0) {
         dmnsn_error(DMNSN_SEVERITY_LOW,
                     "Leaking condition variable in failed allocation.");
       }
+      free(progress->rwlock);
       free(progress->mutex);
       free(progress->cond);
       dmnsn_delete_array(progress->elements);
@@ -77,6 +110,9 @@ void
 dmnsn_delete_progress(dmnsn_progress *progress)
 {
   if (progress) {
+    if (pthread_rwlock_destroy(progress->rwlock) != 0) {
+      dmnsn_error(DMNSN_SEVERITY_LOW, "Leaking rwlock.");
+    }
     if (pthread_mutex_destroy(progress->mutex) != 0) {
       dmnsn_error(DMNSN_SEVERITY_LOW, "Leaking mutex.");
     }
@@ -124,14 +160,14 @@ dmnsn_get_progress(const dmnsn_progress *progress)
   double prog = 0.0;
   unsigned int i, size;
 
-  dmnsn_array_rdlock(progress->elements);
-    size = dmnsn_array_size_unlocked(progress->elements);
+  dmnsn_progress_rdlock(progress);
+    size = dmnsn_array_size(progress->elements);
     for (i = 0; i < size; ++i) {
       element = dmnsn_array_at(progress->elements, size - i - 1);
       prog += element->progress;
       prog /= element->total;
     }
-  dmnsn_array_unlock(progress->elements);
+  dmnsn_progress_unlock(progress);
 
   return prog;
 }
@@ -172,15 +208,15 @@ dmnsn_increment_progress(dmnsn_progress *progress)
   dmnsn_progress_element *element;
   size_t size;
 
-  dmnsn_array_wrlock(progress->elements);
-    size = dmnsn_array_size_unlocked(progress->elements);
+  dmnsn_progress_wrlock(progress);
+    size = dmnsn_array_size(progress->elements);
     element = dmnsn_array_at(progress->elements, size - 1);
     ++element->progress; /* Increment the last element */
 
     while (element->progress >= element->total && size > 1) {
       /* As long as the last element is complete, pop it */
       --size;
-      dmnsn_array_resize_unlocked(progress->elements, size);
+      dmnsn_array_resize(progress->elements, size);
       element = dmnsn_array_at(progress->elements, size - 1);
       ++element->progress; /* Increment the next element */
     }
@@ -188,7 +224,7 @@ dmnsn_increment_progress(dmnsn_progress *progress)
     if (pthread_cond_broadcast(progress->cond) != 0) {
       dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't signal condition variable.");
     }
-  dmnsn_array_unlock(progress->elements);
+  dmnsn_progress_unlock(progress);
 }
 
 /* Immediately set to 100% completion */
@@ -197,13 +233,39 @@ dmnsn_done_progress(dmnsn_progress *progress)
 {
   dmnsn_progress_element *element;
 
-  dmnsn_array_wrlock(progress->elements);
-    dmnsn_array_resize_unlocked(progress->elements, 1);
+  dmnsn_progress_wrlock(progress);
+    dmnsn_array_resize(progress->elements, 1);
     element = dmnsn_array_at(progress->elements, 0);
     element->progress = element->total;
 
     if (pthread_cond_broadcast(progress->cond) != 0) {
       dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't signal condition variable.");
     }
-  dmnsn_array_unlock(progress->elements);
+  dmnsn_progress_unlock(progress);
+}
+
+/* Thread synchronization */
+
+static void
+dmnsn_progress_rdlock(const dmnsn_progress *progress)
+{
+  if (pthread_rwlock_rdlock(progress->rwlock) != 0) {
+    dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't acquire read-lock.");
+  }
+}
+
+static void
+dmnsn_progress_wrlock(dmnsn_progress *progress)
+{
+  if (pthread_rwlock_wrlock(progress->rwlock) != 0) {
+    dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't acquire write-lock.");
+  }
+}
+
+static void
+dmnsn_progress_unlock(const dmnsn_progress *progress)
+{
+  if (pthread_rwlock_unlock(progress->rwlock) != 0) {
+    dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't unlock read-write lock.");
+  }
 }
diff --git a/libdimension/raytrace.c b/libdimension/raytrace.c
index d634747..4af0a75 100644
--- a/libdimension/raytrace.c
+++ b/libdimension/raytrace.c
@@ -101,7 +101,7 @@ dmnsn_raytrace_scene_multithread(dmnsn_raytrace_payload *payload)
   dmnsn_raytrace_payload *payloads;
   pthread_t *threads;
 
-  /* TODO: do this portably */
+  /* Find the number of processors/cores running (TODO: do this portably) */
   nthreads = sysconf(_SC_NPROCESSORS_ONLN);
   if (nthreads < 1) {
     nthreads = 1;