[sysprof] memory: simplify memory recording source

[Christian Hergert <chergert src gnome org>]

commit 36d76402cf2fcf8a1f0f938f8595c62857e3b63b
Author: Christian Hergert <chergert redhat com>
Date:   Tue Oct 16 07:03:19 2018 -0700

    memory: simplify memory recording source
    
    There is certainly more we'll want to do here, but this gets some basics
    in place that will make it easier to render the graph when visualizing.

 lib/sources/sp-memory-source.c | 128 ++++++++++++++++-------------------------
 1 file changed, 51 insertions(+), 77 deletions(-)
---
diff --git a/lib/sources/sp-memory-source.c b/lib/sources/sp-memory-source.c
index 2da7f0c..52cfc3f 100644
--- a/lib/sources/sp-memory-source.c
+++ b/lib/sources/sp-memory-source.c
@@ -55,19 +55,24 @@ typedef struct
   GPid pid;
   int stat_fd;
 
-  /* Keep in this order, so we can address from total */
-  SpCaptureCounterValue mem_total;
-  SpCaptureCounterValue mem_avail;
-  SpCaptureCounterValue mem_free;
-
-  /* Keep in this order, so we can address from size */
-  SpCaptureCounterValue mem_size;
-  SpCaptureCounterValue mem_resident;
-  SpCaptureCounterValue mem_shared;
-  SpCaptureCounterValue mem_text;
-  SpCaptureCounterValue mem_data;
-
-  guint  counter_ids[5];
+  union {
+    struct {
+      SpCaptureCounterValue used;
+      gint64 total;
+      gint64 avail;
+      gint64 free;
+    } sys;
+    struct {
+      SpCaptureCounterValue used;
+      gint64 size;
+      gint64 resident;
+      gint64 shared;
+      gint64 text;
+      gint64 data;
+    } proc;
+  };
+
+  guint counter_ids[1];
 } MemStat;
 
 static void source_iface_init (SpSourceInterface *iface);
@@ -113,6 +118,7 @@ mem_stat_parse_statm (MemStat *st,
                       gchar   *buf)
 {
   g_assert (st != NULL);
+  g_assert (buf != NULL);
 
   sscanf (buf,
           "%"G_GINT64_FORMAT" "
@@ -121,11 +127,13 @@ mem_stat_parse_statm (MemStat *st,
           "%"G_GINT64_FORMAT" "
           "%*1c "
           "%"G_GINT64_FORMAT,
-          &st->mem_size.v64,
-          &st->mem_resident.v64,
-          &st->mem_shared.v64,
-          &st->mem_text.v64,
-          &st->mem_data.v64);
+          &st->proc.size,
+          &st->proc.resident,
+          &st->proc.shared,
+          &st->proc.text,
+          &st->proc.data);
+
+  st->proc.used.vdbl = st->proc.size - st->proc.shared - st->proc.text - st->proc.data;
 }
 
 static void
@@ -136,6 +144,7 @@ mem_stat_parse_meminfo (MemStat *st,
   gchar *save = NULL;
 
   g_assert (st != NULL);
+  g_assert (buf != NULL);
 
   for (;;)
     {
@@ -179,6 +188,9 @@ mem_stat_parse_meminfo (MemStat *st,
 
       *v64ptr = v64;
     }
+
+  /* Create pre-compiled value for used to simplify display */
+  st->sys.used.vdbl = (gdouble)st->sys.total - (gdouble)st->sys.avail;
 }
 
 static void
@@ -221,8 +233,8 @@ mem_stat_publish (MemStat         *st,
                                   -1,
                                   st->pid,
                                   st->counter_ids,
-                                  st->pid == -1 ? &st->mem_total : &st->mem_size,
-                                  st->pid == -1 ? 3 : 5);
+                                  st->pid == -1 ? &st->sys.used : &st->proc.used,
+                                  1);
 }
 
 /**
@@ -272,9 +284,9 @@ sp_memory_source_class_init (SpMemorySourceClass *klass)
 
 #define ADD_OFFSET(n,o) \
   g_hash_table_insert (keys, (gchar *)n, GUINT_TO_POINTER (o))
-  ADD_OFFSET ("MemTotal", G_STRUCT_OFFSET (MemStat, mem_total));
-  ADD_OFFSET ("MemFree", G_STRUCT_OFFSET (MemStat, mem_free));
-  ADD_OFFSET ("MemAvailable", G_STRUCT_OFFSET (MemStat, mem_avail));
+  ADD_OFFSET ("MemTotal", G_STRUCT_OFFSET (MemStat, sys.total));
+  ADD_OFFSET ("MemFree", G_STRUCT_OFFSET (MemStat, sys.free));
+  ADD_OFFSET ("MemAvailable", G_STRUCT_OFFSET (MemStat, sys.avail));
 #undef ADD_OFFSET
 }
 
@@ -328,81 +340,43 @@ sp_memory_source_prepare (SpSource *source)
 
       mem_stat_open (st);
 
-      for (guint j = 0; j < G_N_ELEMENTS (counters); j++)
-        g_strlcpy (counters[j].category, "Memory", sizeof counters[j].category);
-
       if (st->pid == -1)
         {
-          base = sp_capture_writer_request_counter (self->writer, 3);
-
-          g_strlcpy (counters[0].name, "Total", sizeof counters[0].name);
-          g_strlcpy (counters[1].name, "Available", sizeof counters[1].name);
-          g_strlcpy (counters[2].name, "Free",  sizeof counters[2].name);
+          base = sp_capture_writer_request_counter (self->writer, 1);
 
-          g_strlcpy (counters[0].description, "", sizeof counters[0].description);
-          g_strlcpy (counters[1].description, "", sizeof counters[1].description);
-          g_strlcpy (counters[2].description, "", sizeof counters[2].description);
+          g_strlcpy (counters[0].category, "Memory", sizeof counters[0].category);
+          g_strlcpy (counters[0].name, "Used", sizeof counters[0].name);
+          g_strlcpy (counters[0].description, "Memory used by system", sizeof counters[0].description);
 
           counters[0].id = st->counter_ids[0] = base;
-          counters[1].id = st->counter_ids[1] = base + 1;
-          counters[2].id = st->counter_ids[2] = base + 2;
-
-          counters[0].type = SP_CAPTURE_COUNTER_INT64;
-          counters[1].type = SP_CAPTURE_COUNTER_INT64;
-          counters[2].type = SP_CAPTURE_COUNTER_INT64;
-
-          counters[0].value.v64 = 0;
-          counters[1].value.v64 = 0;
-          counters[2].value.v64 = 0;
-
+          counters[0].type = SP_CAPTURE_COUNTER_DOUBLE;
+          counters[0].value.vdbl = 0;
 
           sp_capture_writer_define_counters (self->writer,
                                              SP_CAPTURE_CURRENT_TIME,
                                              -1,
                                              -1,
                                              counters,
-                                             3);
+                                             1);
         }
       else
         {
-          base = sp_capture_writer_request_counter (self->writer, 5);
-
-          g_strlcpy (counters[0].name, "Size", sizeof counters[0].name);
-          g_strlcpy (counters[1].name, "Resident", sizeof counters[1].name);
-          g_strlcpy (counters[2].name, "Shared",  sizeof counters[2].name);
-          g_strlcpy (counters[3].name, "Text",  sizeof counters[3].name);
-          g_strlcpy (counters[4].name, "Data",  sizeof counters[4].name);
+          base = sp_capture_writer_request_counter (self->writer, 1);
 
-          g_strlcpy (counters[0].description, "", sizeof counters[0].description);
-          g_strlcpy (counters[1].description, "", sizeof counters[1].description);
-          g_strlcpy (counters[2].description, "", sizeof counters[2].description);
-          g_strlcpy (counters[3].description, "", sizeof counters[3].description);
-          g_strlcpy (counters[4].description, "", sizeof counters[4].description);
+          g_strlcpy (counters[0].category, "Memory", sizeof counters[0].category);
+          g_strlcpy (counters[0].name, "Used", sizeof counters[0].name);
+          g_strlcpy (counters[0].description, "Memory used by process", sizeof counters[0].description);
 
           counters[0].id = st->counter_ids[0] = base;
-          counters[1].id = st->counter_ids[1] = base + 1;
-          counters[2].id = st->counter_ids[2] = base + 2;
-          counters[3].id = st->counter_ids[3] = base + 3;
-          counters[4].id = st->counter_ids[4] = base + 4;
-
-          counters[0].type = SP_CAPTURE_COUNTER_INT64;
-          counters[1].type = SP_CAPTURE_COUNTER_INT64;
-          counters[2].type = SP_CAPTURE_COUNTER_INT64;
-          counters[3].type = SP_CAPTURE_COUNTER_INT64;
-          counters[4].type = SP_CAPTURE_COUNTER_INT64;
-
-          counters[0].value.v64 = 0;
-          counters[1].value.v64 = 0;
-          counters[2].value.v64 = 0;
-          counters[3].value.v64 = 0;
-          counters[4].value.v64 = 0;
+          counters[0].type = SP_CAPTURE_COUNTER_DOUBLE;
+          counters[0].value.vdbl = 0;
 
           sp_capture_writer_define_counters (self->writer,
                                              SP_CAPTURE_CURRENT_TIME,
                                              -1,
                                              st->pid,
                                              counters,
-                                             5);
+                                             1);
         }
     }
 
@@ -437,9 +411,9 @@ sp_memory_source_start (SpSource *source)
 
   g_assert (SP_IS_MEMORY_SOURCE (self));
 
-  /* Poll 20x/sec for memory stats */
+  /* Poll 4x/sec for memory stats */
   self->timer_source = g_timeout_add_full (G_PRIORITY_HIGH,
-                                           1000 / 20,
+                                           1000 / 4,
                                            (GSourceFunc)sp_memory_source_timer_cb,
                                            self,
                                            NULL);