time sometimes goes backwards (...), do not penalize our QPS trackers

when this happens

diff --git a/pdns/dnsdist.hh b/pdns/dnsdist.hh
index 8f2e7a53798a253208eedc4449a7b3eafa97c2bc..2fe1f8db7fa284e2e7995cd501869924c09b9d95 100644 (file)
--- a/pdns/dnsdist.hh
+++ b/pdns/dnsdist.hh
@@ -423,7 +423,8 @@ public:
   {
     auto delta = d_prev.udiffAndSet();
 
-    d_tokens += 1.0 * rate * (delta/1000000.0);
+    if(delta > 0.0) // time, frequently, does go backwards..
+      d_tokens += 1.0 * rate * (delta/1000000.0);
 
     if(d_tokens > burst) {
       d_tokens = burst;