ProcessingEventsWhileBlocked is relevant only to the current thread

Former-commit-id: b400be68b7a45e73ea851c11dfee3fdcbacb4794

src/networking.cpp

@@ -40,7 +40,7 @@
 #include "aelocker.h"
 
 static void setProtocolError(const char *errstr, client *c);
-std::atomic<int> ProcessingEventsWhileBlocked {0}; /* See processEventsWhileBlocked(). */
+__thread int ProcessingEventsWhileBlocked = 0; /* See processEventsWhileBlocked(). */
 
 /* Return the size consumed from the allocator, for the specified SDS string,
  * including internal fragmentation. This function is used in order to compute

src/server.cpp

@@ -2471,7 +2471,7 @@ void whileBlockedCron() {
     latencyAddSampleIfNeeded("while-blocked-cron",latency);
 }
 
-extern std::atomic<int> ProcessingEventsWhileBlocked;
+extern __thread int ProcessingEventsWhileBlocked;
 
 /* This function gets called every time Redis is entering the
  * main loop of the event driven library, that is, before to sleep