From a131b99082625bde1db5d0c53f1ab6d058e1b7e8 Mon Sep 17 00:00:00 2001
From: martinsumner <martin.sumner@adaptip.co.uk>
Date: Thu, 22 Dec 2016 17:33:14 +0000
Subject: [PATCH] Randomising logging of PUT timings

---
 src/leveled_log.erl | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/src/leveled_log.erl b/src/leveled_log.erl
index 4943289..3d7cba3 100644
--- a/src/leveled_log.erl
+++ b/src/leveled_log.erl
@@ -335,15 +335,24 @@ log_timer(LogReference, Subs, StartTime) ->
 
 put_timing(_Actor, undefined, T0, T1) ->
     {1, {T0, T1}, {T0, T1}};
-put_timing(Actor, {?PUT_TIMING_LOGPOINT, {Total0, Total1}, {Max0, Max1}}, T0, T1) ->
-    LogRef =
-        case Actor of
-            bookie -> "B0012";
-            inker -> "I0019";
-            journal -> "CDB17"
-        end,
-    log(LogRef, [?PUT_TIMING_LOGPOINT, Total0, Total1, Max0, Max1]),
-    put_timing(Actor, undefined, T0, T1);
+put_timing(Actor, {?PUT_TIMING_LOGPOINT, {Total0, Total1}, {Max0, Max1}},
+                                                                    T0, T1) ->
+    RN = random:uniform(?HEAD_TIMING_LOGPOINT),
+    case RN > ?HEAD_TIMING_LOGPOINT div 2 of
+        true ->
+            % log at the timing point less than half the time
+            LogRef =
+                case Actor of
+                    bookie -> "B0012";
+                    inker -> "I0019";
+                    journal -> "CDB17"
+                end,
+            log(LogRef, [?PUT_TIMING_LOGPOINT, Total0, Total1, Max0, Max1]),
+            put_timing(Actor, undefined, T0, T1);
+        false ->
+            % Log some other random time
+            put_timing(Actor, {RN, {Total0, Total1}, {Max0, Max1}}, T0, T1)
+    end;
 put_timing(_Actor, {N, {Total0, Total1}, {Max0, Max1}}, T0, T1) ->
     {N + 1, {Total0 + T0, Total1 + T1}, {max(Max0, T0), max(Max1, T1)}}.