[Core] Implement disagg prefill by StatelessProcessGroup (#10502)

This PR provides initial support for single-node disaggregated prefill in 1P1D scenario.
Signed-off-by: KuntaiDu <kuntai@uchicago.edu>
Co-authored-by: ApostaC <yihua98@uchicago.edu>
Co-authored-by: YaoJiayi <120040070@link.cuhk.edu.cn>

benchmarks/disagg_benchmarks/visualize_benchmark_results.py

@@ -0,0 +1,46 @@
+import json
+
+import matplotlib.pyplot as plt
+import pandas as pd
+
+if __name__ == "__main__":
+
+    data = []
+    for name in ['disagg_prefill', 'chunked_prefill']:
+        for qps in [2, 4, 6, 8]:
+            with open(f"results/{name}-qps-{qps}.json") as f:
+                x = json.load(f)
+                x['name'] = name
+                x['qps'] = qps
+                data.append(x)
+
+    df = pd.DataFrame.from_dict(data)
+    dis_df = df[df['name'] == 'disagg_prefill']
+    chu_df = df[df['name'] == 'chunked_prefill']
+
+    plt.style.use('bmh')
+    plt.rcParams['font.size'] = 20
+
+    for key in [
+            'mean_ttft_ms', 'median_ttft_ms', 'p99_ttft_ms', 'mean_itl_ms',
+            'median_itl_ms', 'p99_itl_ms'
+    ]:
+
+        fig, ax = plt.subplots(figsize=(11, 7))
+        plt.plot(dis_df['qps'],
+                 dis_df[key],
+                 label='disagg_prefill',
+                 marker='o',
+                 linewidth=4)
+        plt.plot(chu_df['qps'],
+                 chu_df[key],
+                 label='chunked_prefill',
+                 marker='o',
+                 linewidth=4)
+        ax.legend()
+
+        ax.set_xlabel('QPS')
+        ax.set_ylabel(key)
+        ax.set_ylim(bottom=0)
+        fig.savefig(f'results/{key}.png')
+        plt.close(fig)