[counters] Introduce variance and units.

mono/utils/mono-counters.c

@@ -20,6 +20,18 @@ static MonoCounter *counters = NULL;
 static int valid_mask = 0;
 static int set_mask = 0;
 
+static int
+mono_counter_get_variance (MonoCounter *counter)
+{
+	return counter->type & MONO_COUNTER_VARIANCE_MASK;
+}
+
+static int
+mono_counter_get_unit (MonoCounter *counter)
+{
+	return counter->type & MONO_COUNTER_UNIT_MASK;
+}
+
 /**
  * mono_counters_enable:
  * @section_mask: a mask listing the sections that will be displayed
@@ -170,7 +182,7 @@ mono_counters_dump_section (int section, FILE *outfile)
 {
 	MonoCounter *counter = counters;
 	while (counter) {
-		if (counter->type & section)
+		if (counter->type & section && mono_counter_get_variance (counter) == MONO_COUNTER_MONOTONIC)
 			dump_counter (counter, outfile);
 		counter = counter->next;
 	}

mono/utils/mono-counters.h

@@ -5,6 +5,7 @@
 #include <mono/utils/mono-publib.h>
 
 enum {
+	/* Counter type, bits 0-7. */
 	MONO_COUNTER_INT,    /* 32 bit int */
 	MONO_COUNTER_UINT,    /* 32 bit uint */
 	MONO_COUNTER_WORD,   /* pointer-sized int */
@@ -16,7 +17,7 @@ enum {
 	MONO_COUNTER_TYPE_MASK = 0xf,
 	MONO_COUNTER_CALLBACK = 128, /* ORed with the other values */
 	MONO_COUNTER_SECTION_MASK = 0xffffff00,
-	/* sections */
+	/* Sections, bits 8-15  */
 	MONO_COUNTER_JIT      = 1 << 8,
 	MONO_COUNTER_GC       = 1 << 9,
 	MONO_COUNTER_METADATA = 1 << 10,
@@ -24,7 +25,24 @@ enum {
 	MONO_COUNTER_SECURITY = 1 << 12,
 	MONO_COUNTER_RUNTIME  = 1 << 13,
 	MONO_COUNTER_SYSTEM   = 1 << 14,
-	MONO_COUNTER_LAST_SECTION
+	MONO_COUNTER_LAST_SECTION,
+
+	/* Unit, bits 16-23 */
+	MONO_COUNTER_UNIT_SHIFT = 16,
+	MONO_COUNTER_UNIT_MASK = 0xFFu << MONO_COUNTER_UNIT_SHIFT,
+	MONO_COUNTER_RAW        = 0 << 16,  /* Raw value */
+	MONO_COUNTER_BYTES      = 1 << 16, /* Quantity of bytes. RSS, active heap, etc */
+	MONO_COUNTER_TIME       = 2 << 16,  /* Time interval in 100ns units. Minor pause, JIT compilation*/
+	MONO_COUNTER_EVENTS     = 3 << 16, /* Number of times the given event happens. Major collections, Compiled methods. */
+	MONO_COUNTER_ITEMS      = 4 << 16, /* Current number of things. Threads, queued jobs.*/
+	MONO_COUNTER_PERCENTAGE = 5 << 16, /* [0-1] Fraction Percentage of something. Load average. */
+
+	/* Monotonicity, bits 24-31 */
+	MONO_COUNTER_VARIANCE_SHIFT = 24,
+	MONO_COUNTER_VARIANCE_MASK = 0xFFu << MONO_COUNTER_VARIANCE_SHIFT,
+	MONO_COUNTER_MONOTONIC      = 0 << 24, /* This counter value always increase/decreases over time. Reported by --stat. */
+	MONO_COUNTER_CONSTANT       = 1 << 24, /* Fixed value. Used by configuration data. */
+	MONO_COUNTER_VARIABLE       = 2 << 24, /* This counter value can be anything on each sampling. Only interesting when sampling. */
 };
 
 MONO_API void mono_counters_enable (int section_mask);