[diffusion] feat: support comparing batch perf (#14738)

Co-authored-by: shuxiguo <shuxiguo@meituan.com>
Co-authored-by: Mick <mickjagger19@icloud.com>

python/sglang/multimodal_gen/benchmarks/compare_perf.py

@@ -1,5 +1,6 @@
 import argparse
 import json
+import os
 import re
 from datetime import datetime
 from typing import Any, Dict, List, Tuple
@@ -108,44 +109,40 @@ def _load_benchmark_file(file_path: str) -> Dict[str, Any]:
         return json.load(f)
 
 
-def compare_benchmarks(
+def _get_status_emoji_from_diff_percent(diff_pct):
-    baseline_path: str, new_path: str, output_format: str = "markdown"
-):
-    """
-    Compares two benchmark JSON files and prints a report.
-    """
-    try:
-        base_data = _load_benchmark_file(baseline_path)
-        new_data = _load_benchmark_file(new_path)
-    except Exception as e:
-        print(f"Error loading benchmark files: {e}")
-        return
-
-    base_e2e = base_data.get("total_duration_ms", 0)
-    new_e2e = new_data.get("total_duration_ms", 0)
-
-    diff_ms, diff_pct = calculate_diff(base_e2e, new_e2e)
-
     if diff_pct < -2.0:
-        status = "✅"
+        return "✅"
     elif diff_pct > 2.0:
-        status = "❌"
+        return "❌"
     else:
-        status = ""
+        return "⚪️"
 
-    # --- Stage Breakdown ---
+
-    base_durations, base_order, base_counts = consolidate_steps(
+def _print_single_comparison_report(
-        base_data.get("steps", [])
+    others_data, base_e2e, combined_order, base_durations, others_processed, base_counts
+):
+    new_data = others_data[0]
+    new_e2e = new_data.get("total_duration_ms", 0)
+    diff_ms, diff_pct = calculate_diff(base_e2e, new_e2e)
+    status = _get_status_emoji_from_diff_percent(diff_pct)
+
+    print("#### 1. High-level Summary")
+    print("| Metric | Baseline | New | Diff | Status |")
+    print("| :--- | :--- | :--- | :--- | :--- |")
+    print(
+        f"| **E2E Latency** | {base_e2e:.2f} ms | {new_e2e:.2f} ms | **{diff_ms:+.2f} ms ({diff_pct:+.1f}%)** | {status} |"
     )
-    new_durations, new_order, new_counts = consolidate_steps(new_data.get("steps", []))
+    print(
+        f"| **Throughput** | {1000 / base_e2e if base_e2e else 0:.2f} req/s | {1000 / new_e2e if new_e2e else 0:.2f} req/s | - | - |"
+    )
+    print("\n")
 
-    # Merge orders: Start with New order (execution order), append any missing from Base
+    print("#### 2. Stage Breakdown")
-    combined_order = list(new_order)
+    print("| Stage Name | Baseline (ms) | New (ms) | Diff (ms) | Diff (%) | Status |")
-    for name in base_order:
+    print("| :--- | :--- | :--- | :--- | :--- | :--- |")
-        if name not in combined_order:
+
-            combined_order.append(name)
+    new_durations, _, new_counts = others_processed[0]
 
-    stage_rows = []
     for stage in combined_order:
         b_val = base_durations.get(stage, 0.0)
         n_val = new_durations.get(stage, 0.0)
@@ -154,7 +151,6 @@ def compare_benchmarks(
 
         s_diff, s_pct = calculate_diff(b_val, n_val)
 
-        # Format count string if aggregated
         count_str = ""
         if stage == "Denoising Loop":
             count_str = (
@@ -163,54 +159,143 @@ def compare_benchmarks(
                 else f" ({b_count}->{n_count} steps)"
             )
 
-        # filter noise: show if diff is > 0.5ms OR if it's a major stage (like Denoising Loop)
+        status_emoji = get_perf_status_emoji(b_val, n_val)
-        # always show Denoising Loop or stages with significant duration/diff
+        print(
-        stage_rows.append((stage + count_str, b_val, n_val, s_diff, s_pct))
+            f"| {stage}{count_str} | {b_val:.2f} | {n_val:.2f} | {s_diff:+.2f} | {s_pct:+.1f}% | {status_emoji} |"
+        )
+
+
+def _print_multi_comparison_report(
+    base_e2e,
+    others_data,
+    other_labels,
+    combined_order,
+    base_durations,
+    others_processed,
+):
+    print("#### 1. High-level Summary")
+    header = "| Metric | Baseline | " + " | ".join(other_labels) + " |"
+    sep = "| :--- | :--- | " + " | ".join([":---"] * len(other_labels)) + " |"
+    print(header)
+    print(sep)
+
+    # E2E Row
+    row_e2e = f"| **E2E Latency** | {base_e2e:.2f} ms |"
+    for i, d in enumerate(others_data):
+        val = d.get("total_duration_ms", 0)
+        diff_ms, diff_pct = calculate_diff(base_e2e, val)
+
+        status = _get_status_emoji_from_diff_percent(diff_pct)
+
+        row_e2e += f" {val:.2f} ms ({diff_pct:+.1f}%) {status} |"
+    print(row_e2e)
+    print("\n")
+
+    print("#### 2. Stage Breakdown")
+    # Header: Stage | Baseline | Label1 | Label2 ...
+    header = "| Stage Name | Baseline | " + " | ".join(other_labels) + " |"
+    sep = "| :--- | :--- | " + " | ".join([":---"] * len(other_labels)) + " |"
+    print(header)
+    print(sep)
+
+    for stage in combined_order:
+        b_val = base_durations.get(stage, 0.0)
+        row_str = f"| {stage} | {b_val:.2f} |"
+
+        for i, (n_durations, _, n_counts) in enumerate(others_processed):
+            n_val = n_durations.get(stage, 0.0)
+            _, s_pct = calculate_diff(b_val, n_val)
+            status_emoji = get_perf_status_emoji(b_val, n_val)
+
+            row_str += f" {n_val:.2f} ({s_pct:+.1f}%) {status_emoji} |"
+        print(row_str)
+
+
+def compare_benchmarks(file_paths: List[str], output_format: str = "markdown"):
+    """
+    Compares benchmark JSON files and prints a report.
+    First file is baseline, others will be compared against it.
+    """
+    if len(file_paths) < 2:
+        print("Error: Need at least 2 files to compare.")
+        return
+
+    try:
+        data_list = [_load_benchmark_file(f) for f in file_paths]
+    except Exception as e:
+        print(f"Error loading benchmark files: {e}")
+        return
+
+    base_data = data_list[0]
+    others_data = data_list[1:]
+
+    # Use filenames as labels if multiple comparisons, else just "New"
+    other_labels = [os.path.basename(p) for p in file_paths[1:]]
+
+    base_e2e = base_data.get("total_duration_ms", 0)
+
+    base_durations, base_order, base_counts = consolidate_steps(
+        base_data.get("steps", [])
+    )
+
+    others_processed = []
+    for d in others_data:
+        dur, order, counts = consolidate_steps(d.get("steps", []))
+        others_processed.append((dur, order, counts))
+
+    combined_order = []
+    # Collect all unique stages maintaining order from newest to baseline
+    for _, order, _ in reversed(others_processed):
+        for name in order:
+            if name not in combined_order:
+                combined_order.append(name)
+    for name in base_order:
+        if name not in combined_order:
+            combined_order.append(name)
 
     if output_format == "markdown":
         print("### Performance Comparison Report\n")
 
-        # Summary Table
+        if len(others_data) == 1:
-        print("#### 1. High-level Summary")
+            _print_single_comparison_report(
-        print("| Metric | Baseline | New | Diff | Status |")
+                others_data,
-        print("| :--- | :--- | :--- | :--- | :--- |")
+                base_e2e,
-        print(
+                combined_order,
-            f"| **E2E Latency** | {base_e2e:.2f} ms | {new_e2e:.2f} ms | **{diff_ms:+.2f} ms ({diff_pct:+.1f}%)** | {status} |"
+                base_durations,
-        )
+                others_processed,
-        print(
+                base_counts,
-            f"| **Throughput** | {1000 / base_e2e if base_e2e else 0:.2f} req/s | {1000 / new_e2e if new_e2e else 0:.2f} req/s | - | - |"
+            )
-        )
+        else:
-        print("\n")
+            _print_multi_comparison_report(
-
+                base_e2e,
-        # Detailed Breakdown
+                others_data,
-        print("#### 2. Stage Breakdown")
+                other_labels,
-        print(
+                combined_order,
-            "| Stage Name | Baseline (ms) | New (ms) | Diff (ms) | Diff (%) | Status |"
+                base_durations,
-        )
+                others_processed,
-        print("| :--- | :--- | :--- | :--- | :--- | :--- |")
-        for name, b, n, d, p in stage_rows:
-            name_str = name
-            status_emoji = get_perf_status_emoji(b, n)
-            print(
-                f"| {name_str} | {b:.2f} | {n:.2f} | {d:+.2f} | {p:+.1f}% | {status_emoji} |"
             )
-        print("\n")
 
+        print("\n")
         # Metadata
         print("<details>")
         print("<summary>Metadata</summary>\n")
         print(f"- Baseline Commit: `{base_data.get('commit_hash', 'N/A')}`")
-        print(f"- New Commit: `{new_data.get('commit_hash', 'N/A')}`")
+        for i, d in enumerate(others_data):
+            label = "New" if len(others_data) == 1 else other_labels[i]
+            print(f"- {label} Commit: `{d.get('commit_hash', 'N/A')}`")
         print(f"- Timestamp: {datetime.now().isoformat()}")
         print("</details>")
 
 
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(
-        description="Compare two sglang-diffusion performance JSON files."
+        description="Compare sglang-diffusion performance JSON files."
+    )
+    parser.add_argument(
+        "files",
+        nargs="+",
+        help="List of JSON files. First is baseline, others are compared against it.",
     )
-    parser.add_argument("baseline", help="Path to the baseline JSON file")
-    parser.add_argument("new", help="Path to the new JSON file")
     args = parser.parse_args()
 
-    compare_benchmarks(args.baseline, args.new)
+    compare_benchmarks(args.files)

python/sglang/multimodal_gen/docs/contributing.md

@@ -39,7 +39,7 @@ For PRs that impact **latency**, **throughput**, or **memory usage**, you **shou
 
 3.  **Compare**: run the compare script, which will print a Markdown table to the console
     ```bash
-    $ python python/sglang/multimodal_gen/benchmarks/compare_perf.py baseline.json new.json
+    $ python python/sglang/multimodal_gen/benchmarks/compare_perf.py baseline.json new.json [new2.json ...]
     ### Performance Comparison Report
     ...
     ```