e2e: reduce load pressure (#6939)

test/e2e/runner/load.go

@@ -105,13 +105,27 @@ func loadGenerate(ctx context.Context, chTx chan<- types.Tx, size int64) {
 		case chTx <- tx:
 			// sleep for a bit before sending the
 			// next transaction.
-			waitTime := (50 * time.Millisecond) + time.Duration(rand.Int63n(int64(time.Second))) // nolint: gosec
-			timer.Reset(waitTime)
+			timer.Reset(loadGenerateWaitTime(size))
 		}
 
 	}
 }
 
+func loadGenerateWaitTime(size int64) time.Duration {
+	const (
+		min = int64(100 * time.Millisecond)
+		max = int64(time.Second)
+	)
+
+	var (
+		baseJitter = rand.Int63n(max-min+1) + min // nolint: gosec
+		sizeFactor = size * int64(time.Millisecond)
+		sizeJitter = rand.Int63n(sizeFactor-min+1) + min // nolint: gosec
+	)
+
+	return time.Duration(baseJitter + sizeJitter)
+}
+
 // loadProcess processes transactions
 func loadProcess(ctx context.Context, testnet *e2e.Testnet, chTx <-chan types.Tx, chSuccess chan<- int) {
 	// Each worker gets its own client to each usable node, which