From 2e94c606b83cd17ab449ee666cb16dae68268669 Mon Sep 17 00:00:00 2001
From: Sam Hocevar <sam@hocevar.net>
Date: Mon, 7 Dec 2009 01:05:31 +0000
Subject: [PATCH] Increase profiling timers' sliding mean accuracy.

---
 caca/caca_internals.h |  5 +++--
 caca/caca_prof.h      | 16 ++++++++--------
 caca/prof.c           | 12 ++----------
 3 files changed, 13 insertions(+), 20 deletions(-)

diff --git a/caca/caca_internals.h b/caca/caca_internals.h
index 03a154a..a4952db 100644
--- a/caca/caca_internals.h
+++ b/caca/caca_internals.h
@@ -24,7 +24,7 @@ typedef struct caca_privevent caca_privevent_t;
 typedef struct caca_figfont caca_figfont_t;
 
 #if !defined(_DOXYGEN_SKIP_ME)
-#   define STAT_VALUES 20
+#   define STAT_VALUES 32
 #   define EVENTBUF_LEN 10
 #   define MAX_DIRTY_COUNT 8
 #endif
@@ -148,8 +148,9 @@ struct caca_timer
 /* Statistic structure for profiling */
 struct caca_stat
 {
+    int itable[STAT_VALUES];
+    int64_t imean;
     char *name;
-    int imean, itable[STAT_VALUES];
 };
 
 /* Private event structure */
diff --git a/caca/caca_prof.h b/caca/caca_prof.h
index 5129997..f75b87c 100644
--- a/caca/caca_prof.h
+++ b/caca/caca_prof.h
@@ -21,15 +21,15 @@
 #if defined PROF && !defined __KERNEL__
 #   define PROFILING_VARS
 
-#   define STAT_IADD(s, n) \
+#   define STAT_IADD(_s, _n) \
       do \
       { \
-        struct caca_stat *ss = s; \
-        int ii, nn = n; \
-        for (ii = STAT_VALUES - 1; ii > 0; ii--) \
-            ss->itable[ii] = ss->itable[ii - 1]; \
-        ss->itable[0] = nn; \
-        ss->imean = ((int64_t)ss->imean * 15 + nn) / 16; \
+        struct caca_stat *s = _s; \
+        int i, n = _n; \
+        for (i = STAT_VALUES - 1; i > 0; i--) \
+            s->itable[i] = s->itable[i - 1]; \
+        s->itable[0] = n; \
+        s->imean = (s->imean * 63 + (int64_t)n * 64 + 32) / 64; \
       } \
       while(0)
 
@@ -38,7 +38,7 @@
 
 #else
 #   define PROFILING_VARS
-#   define STAT_IADD(s) do { } while(0)
+#   define STAT_IADD(_s, _n) do { } while(0)
 #   define START_PROF(obj, fn) do { } while(0)
 #   define STOP_PROF(obj, fn) do { } while(0)
 #endif
diff --git a/caca/prof.c b/caca/prof.c
index 1471573..1b12607 100644
--- a/caca/prof.c
+++ b/caca/prof.c
@@ -45,18 +45,10 @@ void _caca_dump_stats(void)
          for (j = 0; j < STAT_VALUES; j++)
              total += stats[i]->itable[j];
 
-         fprintf(stderr, " %s: last %i mean %i sliding mean %i\n",
+         fprintf(stderr, " %s: last %i sliding mean %i smoothed mean %i\n",
                  stats[i]->name, stats[i]->itable[0],
                  (int)((total + STAT_VALUES / 2) / STAT_VALUES),
-                 stats[i]->imean);
-/*fprintf(stderr, "%i %i %i %i %i %i %i %i %i %i %i %i %i %i %i %i %i %i %i %i\n",
-stats[i]->itable[0], stats[i]->itable[1], stats[i]->itable[2],
-stats[i]->itable[3], stats[i]->itable[4], stats[i]->itable[5],
-stats[i]->itable[6], stats[i]->itable[7], stats[i]->itable[8],
-stats[i]->itable[9], stats[i]->itable[10], stats[i]->itable[11],
-stats[i]->itable[12], stats[i]->itable[13], stats[i]->itable[14],
-stats[i]->itable[15], stats[i]->itable[16], stats[i]->itable[17],
-stats[i]->itable[18], stats[i]->itable[19]);*/
+                 (int)(stats[i]->imean / 64));
     }
 
     fprintf(stderr, "** %i counters dumped **\n", nstats);