[Benchmark] Use `sns.relplot` for plotting (#35027)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

vllm/benchmarks/sweep/plot.py

@@ -346,27 +346,11 @@ def _plot_fig(
         else "(All)"
     )
 
-    g = sns.FacetGrid(df, row="row_group", col="col_group", height=fig_height)
-
-    if row_by and col_by:
-        g.set_titles("{row_name}\n{col_name}")
-    elif row_by:
-        g.set_titles("{row_name}")
-    elif col_by:
-        g.set_titles("{col_name}")
-    else:
-        g.set_titles("")
-
-    if scale_x:
-        g.set(xscale=scale_x)
-    if scale_y:
-        g.set(yscale=scale_y)
-
     if len(curve_by) <= 3:
         hue, style, size, *_ = (*curve_by, None, None, None)
 
-        g.map_dataframe(
-            sns.lineplot,
+        g = sns.relplot(
+            df,
             x=var_x,
             y=var_y,
             hue=hue,
@@ -374,9 +358,11 @@ def _plot_fig(
             size=size,
             markers=True,
             errorbar="sd" if error_bars else None,
+            kind="line",
+            row="row_group",
+            col="col_group",
+            height=fig_height,
         )
-
-        g.add_legend(title=hue)
     else:
         df["curve_group"] = (
             pd.concat(
@@ -387,16 +373,32 @@ def _plot_fig(
             else "(All)"
         )
 
-        g.map_dataframe(
-            sns.lineplot,
+        g = sns.relplot(
+            df,
             x=var_x,
             y=var_y,
             hue="curve_group",
             markers=True,
             errorbar="sd" if error_bars else None,
+            kind="line",
+            row="row_group",
+            col="col_group",
+            height=fig_height,
         )
 
-        g.add_legend()
+    if row_by and col_by:
+        g.set_titles("{row_name}\n{col_name}")
+    elif row_by:
+        g.set_titles("{row_name}")
+    elif col_by:
+        g.set_titles("{col_name}")
+    else:
+        g.set_titles("")
+
+    if scale_x:
+        g.set(xscale=scale_x)
+    if scale_y:
+        g.set(yscale=scale_y)
 
     g.savefig(fig_path, dpi=fig_dpi)
     plt.close(g.figure)