use achieved_rate in the report graph. (#232)

The current analyze plot is generated based on the expected rate. This
may undercover some setup mistake while doing the analysis. Changed to
`achieved_rate`

Author: zetxqx

inference_perf/analysis/analyze.py

@@ -115,9 +115,9 @@ def analyze_reports(report_dir: str) -> None:
                 report_data = json.load(f)
 
             # Get QPS from report file
-            qps = report_data.get("load_summary", {}).get("requested_rate")
+            qps = report_data.get("load_summary", {}).get("achieved_rate")
             if qps is None:
-                logger.warning(f"Could not find requested_rate in {stage_file.name}. Skipping.")
+                logger.warning(f"Could not find achieved_rate in {stage_file.name}. Skipping.")
                 continue
 
             success_data = report_data.get("successes", {})