set minimum value for initial nextGen2 capacity; profile support

makefile

@@ -17,7 +17,7 @@ classpath = classpath
 test = test
 jscheme = /tmp/jscheme
 
-input = $(cls)/GC.class
+input = $(cls)/References.class
 
 cxx = g++
 cc = gcc
@@ -34,6 +34,8 @@ thread-lflags = -lpthread
 cflags = $(warnings) -fPIC -fno-rtti -fno-exceptions -fvisibility=hidden \
 	-I$(src) -I$(bld) $(thread-cflags) -D__STDC_LIMIT_MACROS
 
+lflags = $(thread-lflags) -ldl -lm
+
 ifeq ($(mode),debug)
 cflags += -O0 -g3
 endif
@@ -46,8 +48,10 @@ endif
 ifeq ($(mode),fast)
 cflags += -Os -DNDEBUG -DMONOLITHIC
 endif
-
+ifeq ($(mode),profile)
-lflags = $(thread-lflags) -ldl -lm
+cflags += -Os -pg -DNDEBUG -DMONOLITHIC
+lflags += -pg
+endif
 
 cpp-objects = $(foreach x,$(1),$(patsubst $(2)/%.cpp,$(bld)/%.o,$(x)))
 asm-objects = $(foreach x,$(1),$(patsubst $(2)/%.S,$(bld)/%.o,$(x)))
@@ -141,6 +145,10 @@ $(input): $(classpath-objects)
 run: $(executable) $(input)
 	LD_LIBRARY_PATH=$(bld) $(<) $(args)
 
+.PHONY: run-jscheme
+run-jscheme: $(executable) $(input)
+	LD_LIBRARY_PATH=$(bld) $(<) -cp $(cls):$(jscheme) jscheme/REPL
+
 .PHONY: debug
 debug: $(executable) $(input)
 	LD_LIBRARY_PATH=$(bld) gdb --args $(<) $(args)
@@ -159,6 +167,11 @@ vg-jscheme: $(executable) $(input)
 	LD_LIBRARY_PATH=$(bld) $(vg) $(<) -cp $(cls):$(jscheme) \
 		jscheme/REPL
 
+.PHONY: profile-jscheme
+profile-jscheme: $(executable) $(input)
+	echo '(+ 5 6)' | LD_LIBRARY_PATH=$(bld) $(<) -cp $(cls):$(jscheme) \
+		jscheme/REPL
+
 .PHONY: test
 test: $(executable) $(classpath-objects) $(test-classes)
 	LD_LIBRARY_PATH=$(bld) /bin/bash $(test)/test.sh \

src/heap.cpp

@@ -12,7 +12,10 @@ const unsigned TenureThreshold = 3;
 
 const unsigned Top = ~static_cast<unsigned>(0);
 
+const unsigned InitialGen2CapacityInBytes = 4 * 1024 * 1024;
+
 const bool Verbose = true;
+const bool Verbose2 = false;
 const bool Debug = false;
 
 class Context;
@@ -285,7 +288,6 @@ class Segment {
     map(map)
   {
     if (desired) {
-      assert(context, minimum > 0);
       assert(context, desired >= minimum);
 
       capacity_ = desired;
@@ -297,6 +299,9 @@ class Segment {
         if (data == 0) {
           if (capacity_ > minimum) {
             capacity_ = avg(minimum, capacity_);
+            if (capacity_ == 0) {
+              break;
+            }
           } else {
             abort(context);
           }
@@ -489,7 +494,7 @@ initNextGen1(Context* c, unsigned footprint)
 
   new (&(c->nextGen1)) Segment(c, &(c->nextAgeMap), desired, minimum);
 
-  if (Verbose) {
+  if (Verbose2) {
     fprintf(stderr, "init nextGen1 to %d bytes\n",
             c->nextGen1.capacity() * BytesPerWord);
   }
@@ -509,11 +514,12 @@ initNextGen2(Context* c)
     (&(c->nextGen2), 1, c->pageMap.scale * 1024, &(c->nextPageMap), true);
 
   unsigned minimum = c->gen2.position() + c->tenureFootprint + c->gen2padding;
-  unsigned desired = minimum * 2;
+  unsigned desired = max
+    (minimum * 2, InitialGen2CapacityInBytes / BytesPerWord);
 
   new (&(c->nextGen2)) Segment(c, &(c->nextHeapMap), desired, minimum);
 
-  if (Verbose) {
+  if (Verbose2) {
     fprintf(stderr, "init nextGen2 to %d bytes\n",
             c->nextGen2.capacity() * BytesPerWord);
   }
@@ -1051,12 +1057,15 @@ collect(Context* c, unsigned footprint)
     c->mode = Heap::MajorCollection;
   }
 
+  int64_t then;
   if (Verbose) {
     if (c->mode == Heap::MajorCollection) {
-      fprintf(stderr, "major collection\n");
+      fprintf(stderr, "major collection ");
     } else {
-      fprintf(stderr, "minor collection\n");
+      fprintf(stderr, "minor collection ");
     }
+
+    then = c->system->now();
   }
 
   initNextGen1(c, footprint);
@@ -1070,6 +1079,10 @@ collect(Context* c, unsigned footprint)
   if (c->mode == Heap::MajorCollection) {
     c->gen2.replaceWith(&(c->nextGen2));
   }
+
+  if (Verbose) {
+    fprintf(stderr, "- " LLD "ms\n", (c->system->now() - then));
+  }
 }
 
 class MyHeap: public Heap {