Merge branch 'egil/binary-gc' into ccase/r13b04_dev

* egil/binary-gc:
  Add documentation for binary heap size settings.
  Add tracing capabilities for binary virtual heap
  Add min heap size start options to beam and erl
  Improve binary garbage collection

OTP-8370  The default settings for garbage collection of binaries has been
          adjusted to be less aggressive than in R13B03. It is now also
          possible configure the settings for binary GC. See the
          documentation for spawn_opt/2-5, erlang:system_info/1,
          erlang:system_flag/2, process_flag/2-3, erlang:trace/3, and the
          documenation for erl for the new command line options +hms and
          +hmbs.

1 files changed, 34 insertions, 12 deletions

diff --git a/erts/emulator/beam/erl_gc.c b/erts/emulator/beam/erl_gc.c
index 363f956b58..e9bf37a173 100644
--- a/erts/emulator/beam/erl_gc.c
+++ b/erts/emulator/beam/erl_gc.c
@@ -2031,23 +2031,45 @@ shrink_new_heap(Process *p, Uint new_sz, Eterm *objv, int nobj)
 }
 
 static Uint
-next_vheap_size(Uint vheap, Uint vheap_sz) {
-    if (vheap < H_MIN_SIZE) {
-    	return H_MIN_SIZE;
-    }
+do_next_vheap_size(Uint vheap, Uint vheap_sz) {
+
+    /*                grow
+     *
+     * vheap_sz ======================
+     *
+     * vheap 75% +    grow
+     *          ----------------------
+     *
+     * vheap 25 - 75% same
+     *          ----------------------
+     *
+     * vheap ~ - 25% shrink
+     *
+     *          ----------------------
+     */
 
-    /* grow */
-    if (vheap > vheap_sz) {
-    	return erts_next_heap_size(2*vheap, 0);
+    if (vheap > (Uint) (vheap_sz*3/4)) {
+
+	while(vheap > (Uint) (vheap_sz*3/4)) {
+	    vheap_sz = vheap_sz*2;
+	}
+
+	return erts_next_heap_size(vheap_sz, 0);
     }
-    /* shrink */
-    if ( vheap < vheap_sz/2) {
-	return (Uint)vheap_sz*3/4;
+
+    if (vheap < (Uint) (vheap_sz/4)) {
+	return erts_next_heap_size((Uint) (vheap_sz / 2), 0);
     }
 
     return vheap_sz;
+
 }
 
+static Uint
+next_vheap_size(Process* p, Uint vheap, Uint vheap_sz) {
+    vheap_sz = do_next_vheap_size(vheap, vheap_sz);
+    return vheap_sz < p->min_vheap_size ? p->min_vheap_size : vheap_sz;
+}
 
 static void
 sweep_proc_externals(Process *p, int fullsweep)
@@ -2250,8 +2272,8 @@ sweep_proc_bins(Process *p, int fullsweep)
         FLAGS(p) |= F_NEED_FULLSWEEP;
     }
 
-    BIN_VHEAP_SZ(p) = next_vheap_size(bin_vheap, BIN_VHEAP_SZ(p));
-    BIN_OLD_VHEAP_SZ(p) = next_vheap_size(BIN_OLD_VHEAP(p), BIN_OLD_VHEAP_SZ(p));
+    BIN_VHEAP_SZ(p) = next_vheap_size(p, bin_vheap, BIN_VHEAP_SZ(p));
+    BIN_OLD_VHEAP_SZ(p) = next_vheap_size(p, BIN_OLD_VHEAP(p), BIN_OLD_VHEAP_SZ(p));
     MSO(p).overhead = bin_vheap;
 
     /*