* Increased the maximum profiling caller stack depth significantly.

* Extended the profiling API by an option to record a variable number of
  samples per tick. The stack depth is used as a maximum.
* Added new option "-f" to the "profile" tool. When specified it
  increments the hit counts of all symbols in the full available caller
  stack. I.e. the resulting hit counts will approximate the total time
  spent in each function or any function directly or indirectly called
  by it. Thus "_start" and "main" will usually get 100% and leaf
  functions only what time has actually been spent in them.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27699 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/os/kernel/debugger.h

@@ -367,6 +367,9 @@ typedef struct {
 	area_id				sample_area;	// area into which the sample will be
 										// written
 	int32				stack_depth;	// number of return address per hit
+	bool				variable_stack_depth;
+										// variable number of samples per hit;
+										// cf. debug_profiler_update
 } debug_nub_start_profiler;
 
 typedef struct {
@@ -549,18 +552,22 @@ typedef struct {
 
 typedef struct {
 	debug_origin		origin;
-	int32				image_event;		// number of the last image event;
-											// all samples were recorded after
-											// this event and before the next
-											// one
-	int32				stack_depth;		// number of return addresses per
-											// tick
-	int32				sample_count;		// number of samples in the buffer
-	int32				dropped_ticks;		// number of ticks that had been
-											// dropped, since the buffer was
-											// full
-	bool				stopped;			// if true, the thread is no longer
-											// being profiled
+	int32				image_event;	// number of the last image event; all
+										// samples were recorded after this
+										// event and before the next one
+	int32				stack_depth;	// number of return addresses per tick
+	int32				sample_count;	// number of samples in the buffer
+	int32				dropped_ticks;	// number of ticks that had been
+										// dropped, since the buffer was full
+	bool				variable_stack_depth;
+										// the number of samples per hit is
+										// variable, i.e. the format for the
+										// samples of a hit in the buffer is
+										//   <n> <sample 1> ... <sample n>
+										// instead of
+										//   <sample 1> ... <sample stack_depth>
+	bool				stopped;		// if true, the thread is no longer
+										// being profiled
 } debug_profiler_update;
 
 // B_DEBUGGER_MESSAGE_HANDED_OVER

headers/private/kernel/user_debugger.h

@@ -16,7 +16,7 @@
 
 // limits
 #define B_DEBUG_MIN_PROFILE_INTERVAL			10			/* in us */
-#define B_DEBUG_STACK_TRACE_DEPTH				20
+#define B_DEBUG_STACK_TRACE_DEPTH				128
 #define	B_DEBUG_PROFILE_BUFFER_FLUSH_THRESHOLD	70			/* in % */
 
 
@@ -96,6 +96,8 @@ struct thread_debug_info {
 		int32			image_event;
 			// number of the image event when the first sample was written into
 			// the buffer
+		bool			variable_stack_depth;
+			// record a variable number of samples per hit
 		bool			buffer_full;
 			// indicates that the sample buffer is full
 		union {