From df3d35eedbb1971afb2fddd3395f135ab5a776a7 Mon Sep 17 00:00:00 2001
From: Jonah Williams <jonahwilliams@google.com>
Date: Fri, 23 Aug 2024 11:11:25 -0700
Subject: [PATCH] [devicelan] opt android devices into fixed performance mode.
 (#154016)

See also: https://developer.android.com/games/optimize/adpf/fixed-performance-mode

Should keep benchmarks more stable so A/B comparisons are appropriate without accounting for CPU/GPU throttling.
---
 dev/devicelab/lib/framework/devices.dart | 8 ++++++++
 dev/devicelab/lib/tasks/perf_tests.dart  | 3 +++
 2 files changed, 11 insertions(+)

diff --git a/dev/devicelab/lib/framework/devices.dart b/dev/devicelab/lib/framework/devices.dart
index 6992765576..7a210bcc9b 100644
--- a/dev/devicelab/lib/framework/devices.dart
+++ b/dev/devicelab/lib/framework/devices.dart
@@ -128,6 +128,9 @@ abstract class Device {
   /// A unique device identifier.
   String get deviceId;
 
+  /// Switch the device into fixed/regular performance mode.
+  Future<void> toggleFixedPerformanceMode(bool enable) async {}
+
   /// Whether the device is awake.
   Future<bool> isAwake();
 
@@ -589,6 +592,11 @@ class AndroidDevice extends Device {
   String deviceInfo = '';
   int apiLevel = 0;
 
+  @override
+  Future<void> toggleFixedPerformanceMode(bool enable) async {
+    await shellExec('cmd', <String>['power', 'set-fixed-performance-mode-enabled', if (enable) 'true' else 'false']);
+  }
+
   /// Whether the device is awake.
   @override
   Future<bool> isAwake() async {
diff --git a/dev/devicelab/lib/tasks/perf_tests.dart b/dev/devicelab/lib/tasks/perf_tests.dart
index f8b7e07ff2..28f521587d 100644
--- a/dev/devicelab/lib/tasks/perf_tests.dart
+++ b/dev/devicelab/lib/tasks/perf_tests.dart
@@ -1311,6 +1311,8 @@ class PerfTest {
       late Device selectedDevice;
       selectedDevice = device ?? await devices.workingDevice;
       await selectedDevice.unlock();
+      await selectedDevice.toggleFixedPerformanceMode(true);
+
       final String deviceId = selectedDevice.deviceId;
       final String? localEngine = localEngineFromEnv;
       final String? localEngineHost = localEngineHostFromEnv;
@@ -1415,6 +1417,7 @@ class PerfTest {
       } finally {
         await resetManifest();
         await resetPlist();
+        await selectedDevice.toggleFixedPerformanceMode(false);
       }
 
       final Map<String, dynamic> data = json.decode(