Add trace replay documentation

Signed-off-by: Vincent Gimenes <vincent.gimenes@gmail.com>

Author: VincentG1234

docs/getting-started/benchmark.md

@@ -61,6 +61,7 @@ GuideLLM supports several benchmark profiles and strategies:
 - `constant`: Sends requests at a fixed rate per second
 - `poisson`: Sends requests following a Poisson distribution
 - `sweep`: Automatically determines optimal performance points (default)
+- `replay`: Replays requests from a trace file to reproduce real-world traffic patterns
 
 ### Data Options
 
@@ -76,6 +77,27 @@ For a complete list of options, run:
 guidellm benchmark run --help
 ```
 
+## Trace Replay Benchmarking
+
+For realistic load testing, replay traffic patterns from trace files. Trace files must be JSONL with `timestamp`, `input_length`, and `output_length` fields:
+
+```json
+{"timestamp": 0, "input_length": 256, "output_length": 128}
+{"timestamp": 0.5, "input_length": 512, "output_length": 64}
+```
+
+Run with the `replay` profile:
+
+```bash
+guidellm benchmark \
+  --target "http://localhost:8000" \
+  --data "path/to/trace.jsonl|trace_synthetic" \
+  --profile replay \
+  --rate 1.0
+```
+
+The `rate` parameter acts as a time scale: `1.0` for original speed, `2.0` for 2x faster, `0.5` for half speed.
+
 ## Working with Real Data
 
 While synthetic data is convenient for quick tests, you can benchmark with real-world data:

docs/guides/datasets.md

@@ -131,6 +131,11 @@ GuideLLM supports various file formats for datasets, including text, CSV, JSON,
   {"prompt": "Hello, how are you?", "output_tokens_count": 5, "additional_column": "foo", "additional_column2": "bar"}
   {"prompt": "What is your name?", "output_tokens_count": 3, "additional_column": "baz", "additional_column2": "qux"}
   ```
+- **Trace files (`.jsonl` with `trace_synthetic` type)**: Specialized JSONL files for replay benchmarking with `timestamp`, `input_length`, and `output_length` fields. Used with `--profile replay` to reproduce production traffic patterns. See [Trace Replay Benchmarking](../getting-started/benchmark.md#trace-replay-benchmarking).
+  ```json
+  {"timestamp": 0, "input_length": 256, "output_length": 128}
+  {"timestamp": 0.5, "input_length": 512, "output_length": 64}
+  ```
 - **JSON files (`.json`)**: Where the entire dataset is represented as a JSON array of objects nested under a specific key. To surface the correct key to use, a `--data-column-mapper` argument must be passed in of `"field": "NAME"` for where the array exists. The objects should include `prompt` or other common names for the prompt which will be used as the prompt column. Additional fields can be included based on the previously mentioned aliases for the `--data-column-mapper` argument.
   ```json
   {