SERVER-20167: use atomics for TimerStats

2 files changed, 6 insertions, 10 deletions

diff --git a/src/mongo/db/stats/timer_stats.cpp b/src/mongo/db/stats/timer_stats.cpp
index 1030d296eb4..1fc957cf8b6 100644
--- a/src/mongo/db/stats/timer_stats.cpp
+++ b/src/mongo/db/stats/timer_stats.cpp
@@ -48,9 +48,8 @@ int TimerHolder::recordMillis() {
 }
 
 void TimerStats::recordMillis(int millis) {
-    scoped_spinlock lk(_lock);
-    _num++;
-    _totalMillis += millis;
+    _num.fetchAndAdd(1);
+    _totalMillis.fetchAndAdd(millis);
 }
 
 int TimerStats::record(const Timer& timer) {
@@ -62,9 +61,8 @@ int TimerStats::record(const Timer& timer) {
 BSONObj TimerStats::getReport() const {
     long long n, t;
     {
-        scoped_spinlock lk(_lock);
-        n = _num;
-        t = _totalMillis;
+        n = _num.loadRelaxed();
+        t = _totalMillis.loadRelaxed();
     }
     BSONObjBuilder b(64);
     b.appendNumber("num", n);
diff --git a/src/mongo/db/stats/timer_stats.h b/src/mongo/db/stats/timer_stats.h
index cd444bee9aa..6873cab5afc 100644
--- a/src/mongo/db/stats/timer_stats.h
+++ b/src/mongo/db/stats/timer_stats.h
@@ -30,7 +30,6 @@
 #pragma once
 
 #include "mongo/db/jsobj.h"
-#include "mongo/util/concurrency/spin_lock.h"
 #include "mongo/util/timer.h"
 
 namespace mongo {
@@ -56,9 +55,8 @@ public:
     }
 
 private:
-    mutable SpinLock _lock;
-    long long _num = 0;
-    long long _totalMillis = 0;
+    AtomicUInt64 _num;
+    AtomicUInt64 _totalMillis;
 };
 
 /**