refactor(performance): remove legacy perf configs

Signed-off-by: yaoyu-33 <yaoyu.094@gmail.com>

Author: yaoyu-33

scripts/performance/README.md

@@ -4,11 +4,14 @@
 
 - Scripts defined in `scripts/performance` are recipes optimized for performance. These scripts can launch pre-training experiments on Slurm based clusters.
 
-## Configuration files
+## Performance recipe configs
 
-There are configuration files- `workload_base_configs.py` for supported models in `scripts/performance/configs`.
+Performance-optimized recipes live in `src/megatron/bridge/perf_recipes`. The performance
+launcher resolves recipes from that package by model, task, GPU count, GPU type, precision,
+and config variant.
 
-- You can override the default configs using these files using command line arguments (recommended) or directly updating these files  
+- Prefer command-line overrides for one-off changes.
+- Add or update flat perf recipe functions in `src/megatron/bridge/perf_recipes` for reusable benchmark configs.
 
 ## Setup Instructions
 
@@ -255,7 +258,7 @@ Mounting cached files is not enough by itself. If `HF_HUB_OFFLINE` remains `0`,
 
 ##### Config variant arguments
 
-- `-cv/--config_variant`: Config variant to use (e.g., `"v1"`, `"v2"`). Defaults to `"v2"` (`"v1"` if `"v2"` doens't exist). Use `--list_config_variants` to see available options.
+- `-cv/--config_variant`: Config variant to use. Defaults to `"v2"`, which maps to the suffix-less canonical flat perf recipe. Named variants such as `"large_scale"` are supported when a matching flat recipe exists; removed legacy variants such as `"v1"` fail instead of silently selecting another config. Use `--list_config_variants` to see available options.
 - `--list_config_variants`: List available config variants for the specified model/task/gpu/dtype and interactively select one (with 15s timeout).
 
 ##### Testing arguments

scripts/performance/argument_parser.py

@@ -905,7 +905,10 @@ def parse_cli_args():
         "-cv",
         "--config_variant",
         type=str,
-        help="Config variant for workload base configs (used by setup_experiment.py only). Use --list_config_variants to see available options.",
+        help=(
+            "Flat perf recipe variant for setup_experiment.py. Defaults to v2, the suffix-less canonical recipe. "
+            "Named variants such as large_scale are supported when a matching recipe exists."
+        ),
         default="v2",
     )
     config_variant_args.add_argument(