diff --git a/scripts/base/frameworks/input/readers/benchmark.bro b/scripts/base/frameworks/input/readers/benchmark.bro
index c6a6e88fca..0f3553b117 100644
--- a/scripts/base/frameworks/input/readers/benchmark.bro
+++ b/scripts/base/frameworks/input/readers/benchmark.bro
@@ -11,4 +11,7 @@ export {
 
 	## spreading where usleep = 1000000 / autospread * num_lines
 	const autospread = 0.0 &redef;
+
+	## addition factor for each heartbeat
+	const addfactor = 0 &redef;
 }
diff --git a/src/input.bif b/src/input.bif
index 059a7ec8bf..798759ab66 100644
--- a/src/input.bif
+++ b/src/input.bif
@@ -50,3 +50,4 @@ module InputBenchmark;
 const factor: double;
 const spread: count;
 const autospread: double;
+const addfactor: count;
diff --git a/src/input/readers/Benchmark.cc b/src/input/readers/Benchmark.cc
index d8de8c2538..a17c8a7ff6 100644
--- a/src/input/readers/Benchmark.cc
+++ b/src/input/readers/Benchmark.cc
@@ -24,6 +24,7 @@ Benchmark::Benchmark(ReaderFrontend *frontend) : ReaderBackend(frontend)
 	multiplication_factor = double(BifConst::InputBenchmark::factor);	
 	autospread = double(BifConst::InputBenchmark::autospread);	
 	spread = int(BifConst::InputBenchmark::spread);
+	add = int(BifConst::InputBenchmark::addfactor);
 	autospread_time = 0;
 
 }
@@ -213,6 +214,7 @@ bool Benchmark::DoHeartbeat(double network_time, double current_time)
 {
 	ReaderBackend::DoHeartbeat(network_time, current_time);
 	num_lines = (int) ( (double) num_lines*multiplication_factor);
+	num_lines += add;
 
 	switch ( mode ) {
 		case MANUAL:
@@ -230,6 +232,17 @@ bool Benchmark::DoHeartbeat(double network_time, double current_time)
 
 				SendEvent("lines_changed", 2, v);
 			}
+
+			if ( add != 0 ) {
+				// we have to document at what time we changed the factor to what value.
+				Value** v = new Value*[2];
+				v[0] = new Value(TYPE_COUNT, true);
+				v[0]->val.uint_val = num_lines;
+				v[1] = new Value(TYPE_TIME, true);
+				v[1]->val.double_val = CurrTime();
+
+				SendEvent("lines_changed", 2, v);
+			}
 			
 			if ( autospread != 0.0 ) {
 				autospread_time = (int) ( (double) 1000000 / (autospread * (double) num_lines) );
diff --git a/src/input/readers/Benchmark.h b/src/input/readers/Benchmark.h
index f0bd0c752d..182adcd1af 100644
--- a/src/input/readers/Benchmark.h
+++ b/src/input/readers/Benchmark.h
@@ -42,6 +42,7 @@ private:
 	int spread;
 	double autospread;
 	int autospread_time;
+	int add;
 
 	string RandomString(const int len);