adding x-axis label
adding x-axis label

kubernetes/perf-tests,kubernetes/perf-tests,sjug/perf-tests,sjug/perf-tests,shyamjvs/perf-tests,shyamjvs/perf-tests,kubernetes/perf-tests,sjug/perf-tests,shyamjvs/perf-tests,shyamjvs/perf-tests,sjug/perf-tests,kubernetes/perf-tests,sjug/perf-tests,shyamjvs/perf-tests,kubernetes/perf-tests