feat: Add TTFT and ITL Interpolation to Profiling Script (#1159)

Co-authored-by: root <root@kkranen-dt.nvidia.com>

container/deps/requirements.txt

@@ -31,6 +31,7 @@ protobuf==5.27.3
 pydantic==2.7.1
 pyright
 PyYAML
+scikit-learn
 sentencepiece
 tensorboard==2.19.0
 tensorboardX==2.6.2.2

docs/guides/planner.md

@@ -86,6 +86,8 @@ The following information will be printed out in the terminal:
 2025-05-16 15:20:24 - __main__ - INFO - Suggested planner upper/lower bound for decode kv cache utilization: 0.20/0.10
 ```
 
+After finding the best TP size for prefill and decode, the script will then interpolate the TTFT with ISL and ITL with active KV cache and decode context length. This is to provide a more accurate estimation of the performance when ISL and OSL changes. The results will be saved to `<output_dir>/<decode/prefill>_tp<best_tp>_interploation`.
+
 ## Usage
 The planner is started automatically as part of Dynamo pipelines when running `dynamo serve`. You can configure the planner just as you would any other component in your pipeline either via YAML configuration or through CLI arguments.
 

examples/llm/utils/profile_sla.py

@@ -28,6 +28,8 @@ import matplotlib.pyplot as plt
 import numpy as np
 import requests
 import yaml
+from matplotlib import cm
+from scipy.interpolate import griddata
 
 DECODE_NUM_REQUESTS_RANGE = [
     1,
@@ -274,6 +276,29 @@ def get_port(config: dict) -> int:
         return config["Frontend"]["port"]
 
 
+def shutdown_deployment(dynamo_process):
+    os.killpg(os.getpgid(dynamo_process.pid), signal.SIGINT)
+    dynamo_process.communicate()
+
+    try:
+        current_pid = os.getpid()
+        ps_cmd = ["ps", "-ef"]
+        ps_output = subprocess.check_output(ps_cmd, text=True)
+        for line in ps_output.splitlines():
+            if "python" in line.lower():
+                parts = line.split()
+                if len(parts) >= 2:
+                    try:
+                        pid = int(parts[1])
+                        if pid != current_pid:  # Exclude current process
+                            os.kill(pid, signal.SIGKILL)
+                    except ValueError:
+                        continue
+    except Exception as e:
+        logger.error(f"Error killing Python processes: {e}")
+    time.sleep(5)
+
+
 def wait_for_server_ready(model_name: str, port: int, timeout: int = 300):
     logger.info("Waiting for the server to be ready...")
     endpoint_url = f"http://localhost:{port}/v1/chat/completions"
@@ -332,6 +357,79 @@ def get_gap_result(artifact_dir: str) -> dict:
         return json.load(f)
 
 
+def benchmark_prefill(isl, genai_perf_artifact_dir, model_name, port):
+    logger.info(f"Running genai-perf with isl {isl}")
+    genai_perf_cmd = get_prefill_genai_perf_cmd(
+        isl, genai_perf_artifact_dir, model=model_name, port=port
+    )
+    gap_process = subprocess.Popen(
+        genai_perf_cmd,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        text=True,
+    )
+    stdout, stderr = gap_process.communicate()
+    if gap_process.returncode == 0:
+        logger.info("Genai-perf profiling completed successfully")
+        logger.info(stdout)
+        gap_result = get_gap_result(genai_perf_artifact_dir)
+        return gap_result
+    else:
+        logger.error(f"Genai-perf failed with error code: {gap_process.returncode}")
+        logger.error(f"stderr: {stderr}")
+        return None
+
+
+def benchmark_decode(isl, osl, num_request, genai_perf_artifact_dir, model_name, port):
+    logger.info(f"Profiling decode with num_request {num_request}...")
+
+    # first warm-up the engine by pre-computing all prefill tokens
+    # we use the same random seed to make sure the prompt is the same
+    seed = random.randint(0, 1000000)
+    genai_perf_cmd = get_decode_genai_perf_cmd(
+        args.isl,
+        args.osl,
+        f"{genai_perf_artifact_dir}_warmup",
+        num_request,
+        seed=seed,
+        model=model_name,
+        port=port,
+    )
+    gap_process = subprocess.Popen(
+        genai_perf_cmd,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        text=True,
+    )
+    gap_process.communicate()
+    # then send out the real requests, hopefully, this will skip all prefill computation
+    genai_perf_cmd = get_decode_genai_perf_cmd(
+        args.isl,
+        args.osl,
+        genai_perf_artifact_dir,
+        num_request,
+        seed=seed,
+        model=model_name,
+        port=port,
+    )
+    gap_process = subprocess.Popen(
+        genai_perf_cmd,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        text=True,
+    )
+    stdout, stderr = gap_process.communicate()
+    if gap_process.returncode == 0:
+        logger.info("Genai-perf profiling completed successfully")
+        logger.info(stdout)
+        gap_result = get_gap_result(genai_perf_artifact_dir)
+        return gap_result
+    else:
+        logger.error(f"Genai-perf failed with error code: {gap_process.returncode}")
+        logger.error(f"stderr: {stderr}")
+        return None
+
+
 if __name__ == "__main__":
     parser = argparse.ArgumentParser()
     parser.add_argument(
@@ -355,6 +453,25 @@ if __name__ == "__main__":
     parser.add_argument(
         "--itl", type=int, default=5, help="target Inter Token Latency in ms"
     )
+    # below are arguments used for interpolating TTFT and ITL under different ISL/OSL
+    parser.add_argument(
+        "--max-context-length",
+        type=int,
+        default=16384,
+        help="maximum context length supported by the served model",
+    )
+    parser.add_argument(
+        "--prefill-interpolation-granularity",
+        type=int,
+        default=16,
+        help="how many samples to benchmark to interpolate TTFT under different ISL",
+    )
+    parser.add_argument(
+        "--decode-interpolation-granularity",
+        type=int,
+        default=6,
+        help="how many samples to benchmark to interpolate ITL under different active kv cache size and decode context length",
+    )
     args = parser.parse_args()
 
     with open(args.config, "r") as f:
@@ -379,12 +496,12 @@ if __name__ == "__main__":
     prefill_config = convert_config(config, "prefill")
     for tp_size in profile_tp_size:
         logger.info(f"Profiling prefill with TP size {tp_size}...")
+        prefill_config = set_config_tp_size(prefill_config, tp_size)
         logger.info(f"Dynamo config: {prefill_config}")
 
         work_dir = f"{args.output_dir}/prefill_tp{tp_size}"
         os.makedirs(work_dir, exist_ok=True)
 
-        prefill_config = set_config_tp_size(prefill_config, tp_size)
         prefill_config_fn = f"{work_dir}/config.yaml"
         dynamo_log_fn = f"{work_dir}/dynamo.log"
         with open(prefill_config_fn, "w") as f:
@@ -407,30 +524,17 @@ if __name__ == "__main__":
             break
 
         # run genai-perf
-        logger.info(f"Running genai-perf with isl {args.isl}")
         genai_perf_artifact_dir = f"{work_dir}/gap_isl{args.isl}"
-        genai_perf_cmd = get_prefill_genai_perf_cmd(
-            args.isl, genai_perf_artifact_dir, model=model_name, port=port
-        )
-        gap_process = subprocess.Popen(
-            genai_perf_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True
+        gap_result = benchmark_prefill(
+            args.isl, genai_perf_artifact_dir, model_name, port
         )
-        stdout, stderr = gap_process.communicate()
-        if gap_process.returncode == 0:
-            logger.info("Genai-perf profiling completed successfully")
-            logger.info(stdout)
-            gap_result = get_gap_result(genai_perf_artifact_dir)
+        if gap_result is not None:
             ttft = gap_result["time_to_first_token"]["avg"]
             prefill_tp_size.append(tp_size)
             prefill_ttft.append(ttft)
             prefill_thpt_per_gpu.append(args.isl / ttft / tp_size * 1000)
-        else:
-            logger.error(f"Genai-perf failed with error code: {gap_process.returncode}")
-            logger.error(f"stderr: {stderr}")
 
-        # Send SIGINT to the dynamo process to terminate it gracefully
-        os.killpg(os.getpgid(dynamo_process.pid), signal.SIGINT)
-        dynamo_process.communicate()
+        shutdown_deployment(dynamo_process)
 
     # Plot the results as a 2D scatter plot
     if prefill_tp_size and prefill_ttft and prefill_thpt_per_gpu:
@@ -471,12 +575,12 @@ if __name__ == "__main__":
     decode_config = convert_config(config, "decode")
     for tp_size in profile_tp_size:
         logger.info(f"Profiling decode with TP size {tp_size}...")
+        decode_config = set_config_tp_size(decode_config, tp_size)
         logger.info(f"Dynamo config: {decode_config}")
 
         work_dir = f"{args.output_dir}/decode_tp{tp_size}"
         os.makedirs(work_dir, exist_ok=True)
 
-        decode_config = set_config_tp_size(decode_config, tp_size)
         decode_config_fn = f"{work_dir}/config.yaml"
         dynamo_log_fn = f"{work_dir}/dynamo.log"
         with open(decode_config_fn, "w") as f:
@@ -510,50 +614,16 @@ if __name__ == "__main__":
         engine_decode_itl = []
         engine_decode_thpt_per_gpu = []
         for num_request in sweep_num_request:
-            logger.info(f"Profiling decode with num_request {num_request}...")
-
-            # first warm-up the engine by pre-computing all prefill tokens
-            # we use the same random seed to make sure the prompt is the same
-            seed = random.randint(0, 1000000)
-            genai_perf_artifact_dir = f"{work_dir}/gap_request{num_request}_isl{args.isl}_osl{args.osl}_n{num_request}_warmup"
-            genai_perf_cmd = get_decode_genai_perf_cmd(
-                args.isl,
-                args.osl,
-                genai_perf_artifact_dir,
-                num_request,
-                seed=seed,
-                model=model_name,
-                port=port,
-            )
-            gap_process = subprocess.Popen(
-                genai_perf_cmd,
-                stdout=subprocess.PIPE,
-                stderr=subprocess.PIPE,
-                text=True,
-            )
-            gap_process.communicate()
-            # then send out the real requests, hopefully, this will skip all prefill computation
             genai_perf_artifact_dir = f"{work_dir}/gap_request{num_request}_isl{args.isl}_osl{args.osl}_n{num_request}"
-            genai_perf_cmd = get_decode_genai_perf_cmd(
+            gap_result = benchmark_decode(
                 args.isl,
                 args.osl,
-                genai_perf_artifact_dir,
                 num_request,
-                seed=seed,
-                model=model_name,
-                port=port,
-            )
-            gap_process = subprocess.Popen(
-                genai_perf_cmd,
-                stdout=subprocess.PIPE,
-                stderr=subprocess.PIPE,
-                text=True,
+                genai_perf_artifact_dir,
+                model_name,
+                port,
             )
-            stdout, stderr = gap_process.communicate()
-            if gap_process.returncode == 0:
-                logger.info("Genai-perf profiling completed successfully")
-                logger.info(stdout)
-                gap_result = get_gap_result(genai_perf_artifact_dir)
+            if gap_result is not None:
                 itl = gap_result["inter_token_latency"]["avg"]
                 thpt_per_gpu = gap_result["output_token_throughput"]["avg"] / tp_size
                 engine_decode_itl.append(itl)
@@ -563,15 +633,8 @@ if __name__ == "__main__":
                 decode_thpt_per_gpu.append(thpt_per_gpu)
                 decode_concurrency.append(num_request)
                 decode_kv_cache_size.append(max_kv_tokens)
-            else:
-                logger.error(
-                    f"Genai-perf failed with error code: {gap_process.returncode}"
-                )
-                logger.error(f"stderr: {stderr}")
 
-        # Send SIGINT to the dynamo process to terminate it gracefully
-        os.killpg(os.getpgid(dynamo_process.pid), signal.SIGINT)
-        dynamo_process.communicate()
+        shutdown_deployment(dynamo_process)
 
         # Plot a line in the 2d plot
         plt.plot(engine_decode_itl, engine_decode_thpt_per_gpu, label=f"TP{tp_size}")
@@ -645,3 +708,243 @@ if __name__ == "__main__":
     logger.info(
         f"Suggested planner upper/lower bound for decode kv cache utilization: {min(1, selected_decode_kv_cache_utilization + 0.2):.2f}/{max(0.1, selected_decode_kv_cache_utilization - 0.2):.2f}"
     )
+
+    # interpolate ISL - TTFT with best prefill TP
+    best_prefill_tp = prefill_tp_size[selected_prefill_idx]
+    prefill_isl = []
+    prefill_ttft = []
+    prefill_thpt_per_gpu = []
+    logger.info(
+        f"Profiling prefill under best TP {best_prefill_tp} with different ISL..."
+    )
+    prefill_config = convert_config(config, "prefill")
+    prefill_config = set_config_tp_size(prefill_config, tp_size)
+    logger.info(f"Dynamo config: {prefill_config}")
+
+    work_dir = f"{args.output_dir}/prefill_tp{tp_size}_interpolation"
+    os.makedirs(work_dir, exist_ok=True)
+
+    prefill_config_fn = f"{work_dir}/config.yaml"
+    dynamo_log_fn = f"{work_dir}/dynamo.log"
+    with open(prefill_config_fn, "w") as f:
+        yaml.dump(prefill_config, f)
+
+    # Start the dynamo serve process
+    logger.info(f"Starting dynamo serve with TP size {tp_size}...")
+    dynamo_serve_cmd = get_dynamo_serve_cmd(prefill_config_fn)
+    with open(dynamo_log_fn, "w") as dynamo_log_f:
+        dynamo_process = subprocess.Popen(
+            dynamo_serve_cmd,
+            stdout=dynamo_log_f,
+            stderr=subprocess.STDOUT,
+            text=True,
+            preexec_fn=os.setsid,  # Use process group for clean termination
+        )
+
+    if not wait_for_server_ready(model_name, port):
+        logger.error(f"Server did not become ready, skip profiling tp={tp_size}")
+    else:
+        for isl in range(
+            100,
+            args.max_context_length,
+            (args.max_context_length - 100) // args.prefill_interpolation_granularity,
+        ):
+            # run genai-perf
+            genai_perf_artifact_dir = f"{work_dir}/gap_isl{isl}"
+            gap_result = benchmark_prefill(
+                isl, genai_perf_artifact_dir, model_name, port
+            )
+            if gap_result is not None:
+                ttft = gap_result["time_to_first_token"]["avg"]
+                prefill_isl.append(isl)
+                prefill_ttft.append(ttft)
+                prefill_thpt_per_gpu.append(isl / ttft / best_prefill_tp * 1000)
+
+    shutdown_deployment(dynamo_process)
+
+    # Interpolate prefill_ttft vs prefill_isl with quadratic function (y=ax^2+bx+c)
+    if len(prefill_isl) > 2:
+        logger.info("Interpolating prefill TTFT and throughput vs ISL...")
+
+        # Convert to numpy arrays for easier manipulation
+        prefill_isl_np = np.array(prefill_isl)
+        prefill_ttft_np = np.array(prefill_ttft)
+        prefill_thpt_per_gpu_np = np.array(prefill_thpt_per_gpu)
+
+        # Fit quadratic functions
+        ttft_coeffs = np.polyfit(prefill_isl_np, prefill_ttft_np, 2)
+        thpt_coeffs = np.polyfit(prefill_isl_np, prefill_thpt_per_gpu_np, 2)
+
+        # Create interpolation functions
+        ttft_poly = np.poly1d(ttft_coeffs)
+        thpt_poly = np.poly1d(thpt_coeffs)
+
+        # Generate points for smooth curves
+        x_interp = np.linspace(min(prefill_isl_np), max(prefill_isl_np), 100)
+        ttft_interp = ttft_poly(x_interp)
+        thpt_interp = thpt_poly(x_interp)
+
+        # Plot TTFT vs ISL
+        plt.figure(figsize=(10, 6))
+        plt.scatter(prefill_isl_np, prefill_ttft_np, s=100, label="Measured data")
+        plt.plot(
+            x_interp,
+            ttft_interp,
+            "r-",
+            label=f"Quadratic fit: {ttft_coeffs[0]:.2e}x² + {ttft_coeffs[1]:.2e}x + {ttft_coeffs[2]:.2e}",
+        )
+
+        plt.title("Prefill TTFT vs Input Sequence Length")
+        plt.xlabel("Input Sequence Length (tokens)")
+        plt.ylabel("Time to First Token (ms)")
+        plt.grid(True)
+        plt.legend()
+
+        ttft_plot_path = f"{work_dir}/prefill_ttft_interpolation.png"
+        plt.savefig(ttft_plot_path, dpi=300)
+        logger.info(f"TTFT interpolation plot saved to {ttft_plot_path}")
+        plt.close()
+
+        # Plot Throughput vs ISL
+        plt.figure(figsize=(10, 6))
+        plt.scatter(
+            prefill_isl_np, prefill_thpt_per_gpu_np, s=100, label="Measured data"
+        )
+        plt.plot(
+            x_interp,
+            thpt_interp,
+            "g-",
+            label=f"Quadratic fit: {thpt_coeffs[0]:.2e}x² + {thpt_coeffs[1]:.2e}x + {thpt_coeffs[2]:.2e}",
+        )
+
+        plt.title("Prefill Throughput vs Input Sequence Length")
+        plt.xlabel("Input Sequence Length (tokens)")
+        plt.ylabel("Prefill throughput per GPU (tokens/s/GPU)")
+        plt.grid(True)
+        plt.legend()
+
+        thpt_plot_path = f"{work_dir}/prefill_throughput_interpolation.png"
+        plt.savefig(thpt_plot_path, dpi=300)
+        logger.info(
+            f"Prefill throughput per GPU interpolation plot saved to {thpt_plot_path}"
+        )
+        plt.close()
+    else:
+        logger.warning(
+            "Not enough data points to perform interpolation (need at least 3 points)"
+        )
+
+    # interpolate ITL - Active_KV_Cache - Decode_Context_Length with best decode TP
+    x_kv_usage = []
+    y_context_length = []
+    z_itl = []
+    z_thpt_per_gpu = []
+    best_decode_tp = decode_tp_size[selected_decode_idx]
+    logger.info(f"Profiling decode with TP size {best_decode_tp}...")
+    decode_config = set_config_tp_size(decode_config, best_decode_tp)
+    logger.info(f"Dynamo config: {decode_config}")
+
+    work_dir = f"{args.output_dir}/decode_tp{best_decode_tp}_interpolation"
+    os.makedirs(work_dir, exist_ok=True)
+
+    decode_config_fn = f"{work_dir}/config.yaml"
+    dynamo_log_fn = f"{work_dir}/dynamo.log"
+    with open(decode_config_fn, "w") as f:
+        yaml.dump(decode_config, f)
+
+    # Start the dynamo serve process
+    logger.info(f"Starting dynamo serve with TP size {tp_size}...")
+    dynamo_serve_cmd = get_dynamo_serve_cmd(decode_config_fn)
+    with open(dynamo_log_fn, "w") as dynamo_log_f:
+        dynamo_process = subprocess.Popen(
+            dynamo_serve_cmd,
+            stdout=dynamo_log_f,
+            stderr=subprocess.STDOUT,
+            text=True,
+            preexec_fn=os.setsid,  # Use process group for clean termination
+        )
+
+    if not wait_for_server_ready(model_name, port):
+        logger.error(f"Server did not become ready, skip profiling tp={tp_size}")
+    else:
+        max_kv_tokens = get_kv_cache_size_from_dynamo_log(dynamo_log_fn)
+
+        osl = 500  # not too large to reduce ITL variance, not too small to have stable measurement
+        for isl in range(
+            100,
+            args.max_context_length - osl,
+            (args.max_context_length - osl) // args.decode_interpolation_granularity,
+        ):
+            max_concurrency = max_kv_tokens // (isl + osl)
+            sweep_num_request = list(
+                range(
+                    1,
+                    max_concurrency,
+                    max_concurrency // args.decode_interpolation_granularity,
+                )
+            )
+            for num_request in sweep_num_request:
+                genai_perf_artifact_dir = (
+                    f"{work_dir}/gap_isl{isl}_osl{osl}_n{num_request}"
+                )
+                gap_result = benchmark_decode(
+                    isl, osl, num_request, genai_perf_artifact_dir, model_name, port
+                )
+                if gap_result is not None:
+                    itl = gap_result["inter_token_latency"]["avg"]
+                    x_kv_usage.append((isl + osl / 2) * num_request / max_kv_tokens)
+                    y_context_length.append(isl + osl / 2)
+                    z_itl.append(itl)
+                    z_thpt_per_gpu.append(
+                        gap_result["output_token_throughput"]["avg"] / tp_size
+                    )
+
+        shutdown_deployment(dynamo_process)
+
+        # Save the data points to a .npz file
+        save_path = f"{work_dir}/decode_tp{tp_size}_data.npz"
+        np.savez(
+            save_path,
+            x_kv_usage=np.array(x_kv_usage),
+            y_context_length=np.array(y_context_length),
+            z_itl=np.array(z_itl),
+            z_thpt_per_gpu=np.array(z_thpt_per_gpu),
+        )
+        logger.info(f"Saved data points to {save_path}")
+
+        xi = np.linspace(min(x_kv_usage), max(x_kv_usage), 100)
+        yi = np.linspace(min(y_context_length), max(y_context_length), 100)
+        X, Y = np.meshgrid(xi, yi)
+        Z = griddata((x_kv_usage, y_context_length), z_itl, (X, Y), method="cubic")
+
+        fig = plt.figure(figsize=(12, 10))
+        ax = fig.add_subplot(111, projection="3d")  # type: ignore
+
+        # Create the surface plot with customizations
+        surf = ax.plot_surface(  # type: ignore
+            X,
+            Y,
+            Z,
+            cmap=cm.coolwarm,  # type: ignore
+            linewidth=0.2,
+            antialiased=True,
+            alpha=0.8,
+        )
+
+        # Add a color bar with custom settings
+        cbar = fig.colorbar(surf, ax=ax, shrink=0.5, aspect=5)
+        cbar.set_label("Z Value", fontsize=12)
+        cbar.ax.tick_params(labelsize=10)
+
+        # Add labels with custom font sizes
+        ax.set_xlabel("Active KV Percentage", fontsize=12)
+        ax.set_ylabel("Decode Context Length", fontsize=12)
+        ax.set_zlabel("ITL", fontsize=12)  # type: ignore
+
+        # Set viewing angle
+        ax.view_init(elev=30, azim=45)  # type: ignore
+        ax.grid(True)
+        ax.tick_params(axis="both", which="major", labelsize=10)
+
+        logger.info(f"Saving ITL surface plot to {work_dir}/decode_tp{tp_size}.png")
+        plt.savefig(f"{work_dir}/decode_tp{tp_size}.png", dpi=300, bbox_inches="tight")