Add support to create flame graph with JFR call stack sequence

README.md

@@ -98,6 +98,9 @@ $ ./jfr-flame-graph -h
       -rv, --show-return-value
         Show return value for methods in the stack
         Default: false
+      -rev, --reverse-call-stack
+        Reverse call stacks so that it can show JFR style graph(bottom-up)
+        Default: false
       -st, --start-timestamp
         Start timestamp in seconds for filtering
         Default: -9223372036854775808

src/main/java/com/github/chrishantha/jfr/flamegraph/output/JFRToFlameGraphWriter.java

@@ -93,6 +93,10 @@ public final class JFRToFlameGraphWriter {
             "--event"}, description = "Type of event used to generate the flamegraph", converter = EventType.EventTypeConverter.class)
     EventType eventType = EventType.METHOD_PROFILING_SAMPLE;
 
+    @Parameter(names = {"-rev",
+            "--reverse-call-stack"}, description = "Reverse call stacks so that it can show JFR style graph(bottom-up)")
+    boolean reverseCallStack;
+
     private static final String EVENT_VALUE_STACK = "(stackTrace)";
 
     private static final String PRINT_FORMAT = "%-16s: %s%n";
@@ -236,6 +240,13 @@ private Stack<String> getStack(IEvent event) {
                 stack.push(frameName);
             }
         }
+        if(reverseCallStack){
+            Stack<String> stack_rev = new Stack<>();
+            while(!stack.isEmpty()){
+                stack_rev.push(stack.pop());
+            }
+            stack = stack_rev;
+        }
         return stack;
     }
 

src/main/java/com/github/chrishantha/jfr/flamegraph/output/JsonOutputWriter.java

@@ -77,7 +77,7 @@ public StackFrame(String name) {
             this.name = name;
         }
 
-        public StackFrame addFrame(String frameName) {
+        public StackFrame addFrame(String frameName, long size) {
             if (children == null) {
                 children = new ArrayList<>();
             }
@@ -87,7 +87,7 @@ public StackFrame addFrame(String frameName) {
                 childrenMap.put(frameName, frame);
                 children.add(frame);
             }
-            frame.value++;
+            frame.value += size;
             return frame;
         }
     }
@@ -108,7 +108,7 @@ public void processEvent(long startTimestamp, long endTimestamp, long duration,
         }
 
         while (!stack.empty()) {
-            frame = frame.addFrame(stack.pop());
+            frame = frame.addFrame(stack.pop(), size);
         }
     }
 

src/test/java/com/github/chrishantha/jfr/flamegraph/output/ApplicationTest.java

@@ -85,4 +85,9 @@ public void testEventTypeOptionDefaultValue() throws Exception {
         assertEquals(EventType.METHOD_PROFILING_SAMPLE, jfrToFlameGraphWriter.eventType);
     }
 
+    public void testReverseCallStackValue() throws Exception {
+        String[] args = {"-f", "temp", "-rev"};
+        parseCommands(args);
+        assertTrue(jfrToFlameGraphWriter.reverseCallStack);
+    }
 }