From 2b2e637652902d2da1f9c97f47df4d2c2184aa42 Mon Sep 17 00:00:00 2001
From: Stefan Marr <git@stefan-marr.de>
Date: Mon, 18 Nov 2024 22:12:57 +0000
Subject: [PATCH] Add support for explicitly request a specific scaling
 governor

Signed-off-by: Stefan Marr <git@stefan-marr.de>
---
 rebench/denoise.py        | 32 +++++++++++++++++++++++++-------
 rebench/denoise_client.py |  5 ++++-
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/rebench/denoise.py b/rebench/denoise.py
index ec7f1347..57dbf6c3 100644
--- a/rebench/denoise.py
+++ b/rebench/denoise.py
@@ -186,6 +186,7 @@ def _reset_shielding() -> Union[str, bool]:
 # For intel_pstate systems, there's only powersave and performance
 SCALING_GOVERNOR_POWERSAVE = "powersave"
 SCALING_GOVERNOR_PERFORMANCE = "performance"
+DEFAULT_SCALING_GOVERNOR = SCALING_GOVERNOR_PERFORMANCE
 
 
 def _read_scaling_governor() -> Optional[str]:
@@ -201,10 +202,12 @@ def _read_scaling_governor() -> Optional[str]:
 
 
 def _set_scaling_governor(governor, num_cores) -> str:
-    assert governor in (SCALING_GOVERNOR_POWERSAVE, SCALING_GOVERNOR_PERFORMANCE), (
-        "The scaling governor is expected to be 'performance' or 'powersave', but was "
-        + governor
-    )
+    if governor not in (SCALING_GOVERNOR_POWERSAVE, SCALING_GOVERNOR_PERFORMANCE):
+        print(
+            "The scaling governor is expected to be 'performance' or 'powersave', but was "
+            + governor
+        )
+        sys.exit(EXIT_CODE_INVALID_SETTINGS)
 
     if not num_cores:
         return "failed: num-cores not set"
@@ -368,9 +371,8 @@ def _minimize_noise(args) -> dict:
         result["no_turbo"] = "succeeded" if r is True else r
 
     if args.use_scaling_governor:
-        result["scaling_governor"] = _set_scaling_governor(
-            SCALING_GOVERNOR_PERFORMANCE, num_cores
-        )
+        scaling_governor = args.scaling_governor or DEFAULT_SCALING_GOVERNOR
+        result["scaling_governor"] = _set_scaling_governor(scaling_governor, num_cores)
 
     if args.use_mini_perf_sampling:
         r = _configure_perf_sampling(args.for_profiling)
@@ -515,6 +517,14 @@ def _shell_options():
         dest="use_scaling_governor",
         help="Don't try setting scaling governor",
     )
+    parser.add_argument(
+        "-g",
+        "--governor",
+        action="store",
+        default=None,
+        dest="scaling_governor",
+        help=f"Scaling Governor to set. Default value is '{DEFAULT_SCALING_GOVERNOR}'.",
+    )
     parser.add_argument(
         "-P",
         "--without-min-perf-sampling",
@@ -564,6 +574,7 @@ def _shell_options():
 EXIT_CODE_NUM_CORES_UNSET = 2
 EXIT_CODE_NO_COMMAND_SELECTED = 3
 EXIT_CODE_EXEC_FAILED = 4
+EXIT_CODE_INVALID_SETTINGS = 5
 
 
 def _report_init(result: dict, args):
@@ -630,6 +641,13 @@ def main_func():
 
     paths.set_cset(args.cset_path)
 
+    if args.use_scaling_governor is False and args.scaling_governor is not None:
+        print(
+            "Error: Option -g|--governor can only be set "
+            "when --without-scaling-governor is not set."
+        )
+        return EXIT_CODE_INVALID_SETTINGS
+
     result = {}
 
     if args.command == "init":
diff --git a/rebench/denoise_client.py b/rebench/denoise_client.py
index ed02b2b5..50809ee3 100644
--- a/rebench/denoise_client.py
+++ b/rebench/denoise_client.py
@@ -6,7 +6,7 @@
 from typing import Optional, Tuple
 from cpuinfo import get_cpu_info
 
-from .denoise import paths
+from .denoise import paths, DEFAULT_SCALING_GOVERNOR
 from .model.denoise import Denoise
 from .output import output_as_str
 from .ui import escape_braces
@@ -120,6 +120,9 @@ def _add_denoise_options(cmd: list[str], requested: Denoise):
         options_to_disable += "S"
     if not requested.requested_scaling_governor:
         options_to_disable += "G"
+    elif requested.scaling_governor != DEFAULT_SCALING_GOVERNOR:
+        cmd.append("-g")
+        cmd.append(requested.scaling_governor)
     if not requested.requested_no_turbo:
         options_to_disable += "T"
     if not requested.requested_minimize_perf_sampling: