From 7b18a62c0efbb7541abf1bc8d459bf6c3cf02775 Mon Sep 17 00:00:00 2001
From: Max Semenik <maxsem.wiki@gmail.com>
Date: Fri, 11 Mar 2016 13:11:43 -0800
Subject: [PATCH] Log slow diffs

Change-Id: Id17e116cd58d433bf6bb51c38096727a660135b9
---
 includes/diff/DifferenceEngine.php | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/includes/diff/DifferenceEngine.php b/includes/diff/DifferenceEngine.php
index a1a1bb0497..f2630d935d 100644
--- a/includes/diff/DifferenceEngine.php
+++ b/includes/diff/DifferenceEngine.php
@@ -846,8 +846,13 @@ class DifferenceEngine extends ContextSource {
 
 		$result = $this->textDiff( $otext, $ntext );
 
-		$time = microtime( true ) - $time;
-		$this->getStats()->timing( 'diff_time', $time * 1000 );
+		$time = intval( ( microtime( true ) - $time ) * 1000 );
+		$this->getStats()->timing( 'diff_time', $time );
+		// Log requests slower than 99th percentile
+		if ( $time > 100 && $this->mOldPage && $this->mNewPage ) {
+			wfDebugLog( 'diff',
+				"$time ms diff: {$this->mOldid} -> {$this->mNewid} {$this->mNewPage}" );
+		}
 
 		return $result;
 	}
-- 
2.20.1