  To cope with the massive growth of semantic data streams, several RDF Stream
Processing (RSP) engines have been implemented. The efficiency of their
throughput, latency and memory consumption can be evaluated using available
benchmarks such as LSBench and City- Bench. Nevertheless, these benchmarks lack
an in-depth performance evaluation as some measurement metrics have not been
considered. The main goal of this paper is to analyze the performance of two
popular RSP engines, namely C-SPARQL and CQELS, when varying a set of
performance metrics. More precisely, we evaluate the impact of stream rate,
number of streams and window size on execution time as well as on memory
consumption.
