X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;ds=inline;f=lib%2Fsorter%2Farray.c;h=43b02fabb9cad171b535c883117e30a94cf1ccb1;hb=6bd2ff95b10c8c409eb178684294f1d17d79265b;hp=2eae93edbbe09352ffdadafd8ad68efd13cd3c59;hpb=d02d92d8402023e96465e7f8edbabd70fe96df06;p=libucw.git

diff --git a/lib/sorter/array.c b/lib/sorter/array.c
index 2eae93ed..43b02fab 100644
--- a/lib/sorter/array.c
+++ b/lib/sorter/array.c
@@ -15,12 +15,15 @@
 #include <string.h>
 #include <alloca.h>
 
-#define ASORT_MIN_RADIX 5000		// FIXME: var?
 #define ASORT_MIN_SHIFT 2
 
+#define ASORT_TRACE(x...) ASORT_XTRACE(1, x)
+#define ASORT_XTRACE(level, x...) do { if (sorter_trace_array >= level) msg(L_DEBUG, x); } while(0)
+
 static void
 asort_radix(struct asort_context *ctx, void *array, void *buffer, uns num_elts, uns hash_bits, uns swapped_output)
 {
+  // swap_output == 0 if result should be returned in `array', otherwise in `buffer'
   uns buckets = (1 << ctx->radix_bits);
   uns shift = (hash_bits > ctx->radix_bits) ? (hash_bits - ctx->radix_bits) : 0;
   uns cnt[buckets];
@@ -29,7 +32,7 @@ asort_radix(struct asort_context *ctx, void *array, void *buffer, uns num_elts,
   static int reported[64];
   if (!reported[hash_bits]++)
 #endif
-  DBG(">>> n=%d h=%d s=%d sw=%d", num_elts, hash_bits, shift, swapped_output);
+  DBG(">>> n=%u h=%d s=%d sw=%d", num_elts, hash_bits, shift, swapped_output);
 
   bzero(cnt, sizeof(cnt));
   ctx->radix_count(array, num_elts, cnt, shift);
@@ -48,7 +51,7 @@ asort_radix(struct asort_context *ctx, void *array, void *buffer, uns num_elts,
   for (uns i=0; i<buckets; i++)
     {
       uns n = cnt[i] - pos;
-      if (n < ASORT_MIN_RADIX || shift < ASORT_MIN_SHIFT)
+      if (n < ctx->radix_threshold || shift < ASORT_MIN_SHIFT)
 	{
 	  ctx->quicksort(buffer, n);
 	  if (!swapped_output)
@@ -72,6 +75,15 @@ static uns asort_threads_use_count;
 static uns asort_threads_ready;
 static struct worker_pool asort_thread_pool;
 
+static uns
+rs_estimate_stack(void)
+{
+  // Stack space needed by the recursive radix-sorter
+  uns ctrsize = sizeof(uns) * (1 << CONFIG_UCW_RADIX_SORTER_BITS);
+  uns maxdepth = (64 / CONFIG_UCW_RADIX_SORTER_BITS) + 1;
+  return ctrsize * maxdepth;
+}
+
 void
 asort_start_threads(uns run)
 {
@@ -79,8 +91,11 @@ asort_start_threads(uns run)
   asort_threads_use_count++;
   if (run && !asort_threads_ready)
     {
-      SORT_XTRACE(2, "Initializing thread pool (%d threads)", sorter_threads);
+      // XXX: If somebody overrides the radix-sorter parameters to insane values,
+      // he also should override the stack size to insane values.
+      asort_thread_pool.stack_size = default_thread_stack_size + rs_estimate_stack();
       asort_thread_pool.num_threads = sorter_threads;
+      ASORT_TRACE("Initializing thread pool (%d threads, %dK stack)", sorter_threads, asort_thread_pool.stack_size >> 10);
       worker_pool_init(&asort_thread_pool);
       asort_threads_ready = 1;
     }
@@ -93,7 +108,7 @@ asort_stop_threads(void)
   ucwlib_lock();
   if (!--asort_threads_use_count && asort_threads_ready)
     {
-      SORT_XTRACE(2, "Shutting down thread pool");
+      ASORT_TRACE("Shutting down thread pool");
       worker_pool_cleanup(&asort_thread_pool);
       asort_threads_ready = 0;
     }
@@ -113,16 +128,17 @@ static void
 qs_handle_work(struct worker_thread *thr UNUSED, struct work *ww)
 {
   struct qs_work *w = (struct qs_work *) ww;
+  struct asort_context *ctx = w->ctx;
 
-  DBG("Thread %d: got %d elts", thr->id, w->num_elts);
-  if (w->num_elts * w->ctx->elt_size < sorter_thread_threshold)
+  DBG("Thread %d: got %u elts", thr->id, w->num_elts);
+  if (w->num_elts < ctx->thread_threshold)
     {
-      w->ctx->quicksort(w->array, w->num_elts);
+      ctx->quicksort(w->array, w->num_elts);
       w->left = w->right = LR_UNDEF;
     }
   else
-    w->ctx->quicksplit(w->array, w->num_elts, &w->left, &w->right);
-  DBG("Thread %d: returning l=%d r=%d", thr->id, w->left, w->right);
+    ctx->quicksplit(w->array, w->num_elts, &w->left, &w->right);
+  DBG("Thread %d: returning l=%u r=%u", thr->id, w->left, w->right);
 }
 
 static struct qs_work *
@@ -182,7 +198,7 @@ threaded_quicksort(struct asort_context *ctx)
 struct rs_work {
   struct work w;
   struct asort_context *ctx;
-  void *in, *out;
+  void *array, *buffer;		// Like asort_radix().
   uns num_elts;
   uns shift;
   uns swap_output;
@@ -194,8 +210,8 @@ rs_count(struct worker_thread *thr UNUSED, struct work *ww)
 {
   struct rs_work *w = (struct rs_work *) ww;
 
-  DBG("Thread %d: Counting %d items, shift=%d", thr->id, w->num_elts, w->shift);
-  w->ctx->radix_count(w->in, w->num_elts, w->cnt, w->shift);
+  DBG("Thread %d: Counting %u items, shift=%d", thr->id, w->num_elts, w->shift);
+  w->ctx->radix_count(w->array, w->num_elts, w->cnt, w->shift);
   DBG("Thread %d: Counting done", thr->id);
 }
 
@@ -204,8 +220,8 @@ rs_split(struct worker_thread *thr UNUSED, struct work *ww)
 {
   struct rs_work *w = (struct rs_work *) ww;
 
-  DBG("Thread %d: Splitting %d items, shift=%d", thr->id, w->num_elts, w->shift);
-  w->ctx->radix_split(w->in, w->out, w->num_elts, w->cnt, w->shift);
+  DBG("Thread %d: Splitting %u items, shift=%d", thr->id, w->num_elts, w->shift);
+  w->ctx->radix_split(w->array, w->buffer, w->num_elts, w->cnt, w->shift);
   DBG("Thread %d: Splitting done", thr->id);
 }
 
@@ -214,16 +230,30 @@ rs_finish(struct worker_thread *thr UNUSED, struct work *ww)
 {
   struct rs_work *w = (struct rs_work *) ww;
 
-  DBG("Thread %d: Finishing %d items, shift=%d", thr->id, w->num_elts, w->shift);
-  if (w->shift < ASORT_MIN_SHIFT || w->num_elts < ASORT_MIN_RADIX)
+  if (thr)
+    DBG("Thread %d: Finishing %u items, shift=%d", thr->id, w->num_elts, w->shift);
+  if (w->shift < ASORT_MIN_SHIFT || w->num_elts < w->ctx->radix_threshold)
     {
-      w->ctx->quicksort(w->out, w->num_elts);
-      if (!w->swap_output)
-	memcpy(w->in, w->out, w->num_elts * w->ctx->elt_size);
+      w->ctx->quicksort(w->array, w->num_elts);
+      if (w->swap_output)
+	memcpy(w->buffer, w->array, w->num_elts * w->ctx->elt_size);
     }
   else
-    asort_radix(w->ctx, w->out, w->in, w->num_elts, w->shift, !w->swap_output);
-  DBG("Thread %d: Finishing done", thr->id);
+    asort_radix(w->ctx, w->array, w->buffer, w->num_elts, w->shift, w->swap_output);
+  if (thr)
+    DBG("Thread %d: Finishing done", thr->id);
+}
+
+static void
+rs_wait_small(struct asort_context *ctx)
+{
+  struct rs_work *w;
+
+  while (w = (struct rs_work *) work_wait(ctx->rs_work_queue))
+    {
+      DBG("Reaping small chunk of %u items", w->num_elts);
+      ep_free(ctx->eltpool, w);
+    }
 }
 
 static void
@@ -233,7 +263,10 @@ rs_radix(struct asort_context *ctx, void *array, void *buffer, uns num_elts, uns
   uns shift = (hash_bits > ctx->radix_bits) ? (hash_bits - ctx->radix_bits) : 0;
   uns cnt[buckets];
   uns blksize = num_elts / sorter_threads;
-  DBG(">>> n=%d h=%d s=%d blk=%d sw=%d", num_elts, hash_bits, shift, blksize, swapped_output);
+  DBG(">>> n=%u h=%d s=%d blk=%u sw=%d", num_elts, hash_bits, shift, blksize, swapped_output);
+
+  // If there are any small chunks in progress, wait for them to finish
+  rs_wait_small(ctx);
 
   // Start parallel counting
   void *iptr = array;
@@ -243,13 +276,14 @@ rs_radix(struct asort_context *ctx, void *array, void *buffer, uns num_elts, uns
       w->w.priority = 0;
       w->w.go = rs_count;
       w->ctx = ctx;
-      w->in = iptr;
-      w->out = ctx->buffer;
+      w->array = iptr;
+      w->buffer = buffer;
       w->num_elts = blksize;
       if (i == sorter_threads-1)
 	w->num_elts += num_elts % sorter_threads;
       w->shift = shift;
       iptr += w->num_elts * ctx->elt_size;
+      bzero(w->cnt, sizeof(uns) * buckets);
       work_submit(ctx->rs_work_queue, &w->w);
     }
 
@@ -297,19 +331,30 @@ rs_radix(struct asort_context *ctx, void *array, void *buffer, uns num_elts, uns
   for (uns i=0; i<buckets; i++)
     {
       uns n = cnt[i] - pos;
-      if (n < sorter_thread_threshold)
+      if (!n)
+	continue;
+      if (n < ctx->thread_threshold || shift < ASORT_MIN_SHIFT)
 	{
 	  struct rs_work *w = ep_alloc(ctx->eltpool);
 	  w->w.priority = 0;
 	  w->w.go = rs_finish;
 	  w->ctx = ctx;
-	  w->in = array;
-	  w->out = buffer;
+	  w->array = buffer;
+	  w->buffer = array;
 	  w->num_elts = n;
 	  w->shift = shift;
-	  w->swap_output = swapped_output;
-	  clist_add_tail(&ctx->rs_bits, &w->w.n);
-	  DBG("Scheduling block %d+%d", pos, n);
+	  w->swap_output = !swapped_output;
+	  if (n < ctx->thread_chunk)
+	    {
+	      DBG("Sorting block %u+%u inline", pos, n);
+	      rs_finish(NULL, &w->w);
+	      ep_free(ctx->eltpool, w);
+	    }
+	  else
+	    {
+	      DBG("Scheduling block %u+%u", pos, n);
+	      work_submit(ctx->rs_work_queue, &w->w);
+	    }
 	}
       else
 	rs_radix(ctx, buffer, array, n, shift, !swapped_output);
@@ -320,7 +365,7 @@ rs_radix(struct asort_context *ctx, void *array, void *buffer, uns num_elts, uns
 }
 
 static void
-threaded_radixsort(struct asort_context *ctx)
+threaded_radixsort(struct asort_context *ctx, uns swap)
 {
   struct work_queue q;
 
@@ -334,23 +379,18 @@ threaded_radixsort(struct asort_context *ctx)
   for (uns i=0; i<sorter_threads; i++)
     ctx->rs_works[i] = big_alloc(sizeof(struct rs_work) + sizeof(uns) * (1 << ctx->radix_bits));
 
-  // Prepare work structures for all remaining small bits which will be sorted later.
-  clist_init(&ctx->rs_bits);
+  // Prepare a pool for all remaining small bits which will be sorted on background.
   ctx->eltpool = ep_new(sizeof(struct rs_work), 1000);
 
   // Do the big splitting
-  // FIXME: Set the swap bit carefully.
-  rs_radix(ctx, ctx->array, ctx->buffer, ctx->num_elts, ctx->hash_bits, 0);
+  rs_radix(ctx, ctx->array, ctx->buffer, ctx->num_elts, ctx->hash_bits, swap);
   for (uns i=0; i<sorter_threads; i++)
     big_free(ctx->rs_works[i], sizeof(struct rs_work) + sizeof(uns) * (1 << ctx->radix_bits));
 
   // Finish the small blocks
-  struct rs_work *w, *tmp;
-  CLIST_WALK_DELSAFE(w, ctx->rs_bits, tmp)
-    work_submit(&q, &w->w);
-  while (work_wait(&q))
-    ;
+  rs_wait_small(ctx);
 
+  ASSERT(!ctx->eltpool->num_allocated);
   ep_delete(ctx->eltpool);
   work_queue_cleanup(&q);
   asort_stop_threads();
@@ -363,15 +403,38 @@ void asort_stop_threads(void) { }
 
 #endif
 
+static uns
+predict_swap(struct asort_context *ctx)
+{
+  uns bits = ctx->radix_bits;
+  uns elts = ctx->num_elts;
+  uns swap = 0;
+
+  while (elts >= ctx->radix_threshold && bits >= ASORT_MIN_SHIFT)
+    {
+      DBG("Predicting pass: %u elts, %d bits", elts, bits);
+      swap = !swap;
+      elts >>= ctx->radix_bits;
+      bits = MAX(bits, ctx->radix_bits) - ctx->radix_bits;
+    }
+  return swap;
+}
+
 void
 asort_run(struct asort_context *ctx)
 {
-  SORT_XTRACE(10, "Array-sorting %d items per %d bytes, hash_bits=%d", ctx->num_elts, ctx->elt_size, ctx->hash_bits);
+  ctx->thread_threshold = MIN(sorter_thread_threshold / ctx->elt_size, ~0U);
+  ctx->thread_chunk = MIN(sorter_thread_chunk / ctx->elt_size, ~0U);
+  ctx->radix_threshold = MIN(sorter_radix_threshold / ctx->elt_size, ~0U);
+
+  ASORT_TRACE("Array-sorting %u items per %u bytes, hash_bits=%d", ctx->num_elts, ctx->elt_size, ctx->hash_bits);
+  ASORT_XTRACE(2, "Limits: thread_threshold=%u, thread_chunk=%u, radix_threshold=%u",
+    	ctx->thread_threshold, ctx->thread_chunk, ctx->radix_threshold);
   uns allow_threads UNUSED = (sorter_threads > 1 &&
-			      ctx->num_elts * ctx->elt_size >= sorter_thread_threshold &&
+			      ctx->num_elts >= ctx->thread_threshold &&
 			      !(sorter_debug & SORT_DEBUG_ASORT_NO_THREADS));
 
-  if (ctx->num_elts < ASORT_MIN_RADIX ||
+  if (ctx->num_elts < ctx->radix_threshold ||
       ctx->hash_bits <= ASORT_MIN_SHIFT ||
       !ctx->radix_split ||
       (sorter_debug & SORT_DEBUG_ASORT_NO_RADIX))
@@ -379,28 +442,35 @@ asort_run(struct asort_context *ctx)
 #ifdef CONFIG_UCW_THREADS
       if (allow_threads)
 	{
-	  SORT_XTRACE(12, "Decided to use parallel quicksort");
+	  ASORT_XTRACE(2, "Decided to use parallel quicksort");
 	  threaded_quicksort(ctx);
-	  return;
 	}
+      else
 #endif
-      SORT_XTRACE(12, "Decided to use sequential quicksort");
-      ctx->quicksort(ctx->array, ctx->num_elts);
+	{
+	  ASORT_XTRACE(2, "Decided to use sequential quicksort");
+	  ctx->quicksort(ctx->array, ctx->num_elts);
+	}
     }
   else
     {
+      uns swap = predict_swap(ctx);
 #ifdef CONFIG_UCW_THREADS
       if (allow_threads)
 	{
-	  SORT_XTRACE(12, "Decided to use parallel radix-sort");
-	  threaded_radixsort(ctx);
+	  ASORT_XTRACE(2, "Decided to use parallel radix-sort (swap=%d)", swap);
+	  threaded_radixsort(ctx, swap);
 	  return;
 	}
+      else
 #endif
-      SORT_XTRACE(12, "Decided to use sequential radix-sort");
-      // FIXME: select dest buffer
-      asort_radix(ctx, ctx->array, ctx->buffer, ctx->num_elts, ctx->hash_bits, 0);
+	{
+	  ASORT_XTRACE(2, "Decided to use sequential radix-sort (swap=%d)", swap);
+	  asort_radix(ctx, ctx->array, ctx->buffer, ctx->num_elts, ctx->hash_bits, swap);
+	}
+      if (swap)
+	ctx->array = ctx->buffer;
     }
 
-  SORT_XTRACE(11, "Array-sort finished");
+  ASORT_XTRACE(2, "Array-sort finished");
 }