commit dea1ac5f79d7fe18283c15c9a08599284c36d5f7
author Alec Mouri <alecmouri@google.com> Wed Jun 23 18:12:18 2021 -0700
committer Alec Mouri <alecmouri@google.com> Mon Jun 28 16:33:26 2021 -0700
tree d474e7e82fa83c41da7636fde530eafd7bb9ac2c
parent 076276f7b8b5e0501a9f96e564d655020128dc31

Disable expensive rendering during static screen

Locking the GPU frequency to a high value causes a power regression, so
when there's no screen updates we should disable expensive rendering -
previously expensive rendering would always be enabled if the previous
frame required expensive rendering.

Bug: 188625644
Test: Swipe to recents and monitor gpu clock info
Change-Id: Ie41fa6286e851c0390295672b399ce29419ea90b

services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp

diff --git a/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp b/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
index 901e19a..1765caf 100644
--- a/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
+++ b/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
@@ -32,6 +32,7 @@
 #include "../SurfaceFlingerProperties.h"
 
 #include "PowerAdvisor.h"
+#include "SurfaceFlinger.h"
 
 namespace android {
 namespace Hwc2 {
@@ -61,14 +62,22 @@
 
 } // namespace
 
-PowerAdvisor::PowerAdvisor()
-      : mUseUpdateImminentTimer(getUpdateTimeout() > 0),
-        mUpdateImminentTimer(
+PowerAdvisor::PowerAdvisor(SurfaceFlinger& flinger)
+      : mFlinger(flinger),
+        mUseScreenUpdateTimer(getUpdateTimeout() > 0),
+        mScreenUpdateTimer(
                 "UpdateImminentTimer", OneShotTimer::Interval(getUpdateTimeout()),
                 /* resetCallback */ [this] { mSendUpdateImminent.store(false); },
-                /* timeoutCallback */ [this] { mSendUpdateImminent.store(true); }) {
-    if (mUseUpdateImminentTimer) {
-        mUpdateImminentTimer.start();
+                /* timeoutCallback */
+                [this] {
+                    mSendUpdateImminent.store(true);
+                    mFlinger.disableExpensiveRendering();
+                }) {}
+
+void PowerAdvisor::init() {
+    // Defer starting the screen update timer until SurfaceFlinger finishes construction.
+    if (mUseScreenUpdateTimer) {
+        mScreenUpdateTimer.start();
     }
 }
 
@@ -122,8 +131,8 @@
         }
     }
 
-    if (mUseUpdateImminentTimer) {
-        mUpdateImminentTimer.reset();
+    if (mUseScreenUpdateTimer) {
+        mScreenUpdateTimer.reset();
     }
 }
 

services/surfaceflinger/DisplayHardware/PowerAdvisor.h

diff --git a/services/surfaceflinger/DisplayHardware/PowerAdvisor.h b/services/surfaceflinger/DisplayHardware/PowerAdvisor.h
index 95eb0e2..f2d0766 100644
--- a/services/surfaceflinger/DisplayHardware/PowerAdvisor.h
+++ b/services/surfaceflinger/DisplayHardware/PowerAdvisor.h
@@ -25,14 +25,20 @@
 #include "DisplayIdentification.h"
 
 namespace android {
+
+class SurfaceFlinger;
+
 namespace Hwc2 {
 
 class PowerAdvisor {
 public:
     virtual ~PowerAdvisor();
 
+    // Initializes resources that cannot be initialized on construction
+    virtual void init() = 0;
     virtual void onBootFinished() = 0;
     virtual void setExpensiveRenderingExpected(DisplayId displayId, bool expected) = 0;
+    virtual bool isUsingExpensiveRendering() = 0;
     virtual void notifyDisplayUpdateImminent() = 0;
 };
 
@@ -50,11 +56,13 @@
         virtual bool notifyDisplayUpdateImminent() = 0;
     };
 
-    PowerAdvisor();
+    PowerAdvisor(SurfaceFlinger& flinger);
     ~PowerAdvisor() override;
 
+    void init() override;
     void onBootFinished() override;
     void setExpensiveRenderingExpected(DisplayId displayId, bool expected) override;
+    bool isUsingExpensiveRendering() override { return mNotifiedExpensiveRendering; }
     void notifyDisplayUpdateImminent() override;
 
 private:
@@ -67,9 +75,10 @@
     std::unordered_set<DisplayId> mExpensiveDisplays;
     bool mNotifiedExpensiveRendering = false;
 
-    const bool mUseUpdateImminentTimer;
+    SurfaceFlinger& mFlinger;
+    const bool mUseScreenUpdateTimer;
     std::atomic_bool mSendUpdateImminent = true;
-    scheduler::OneShotTimer mUpdateImminentTimer;
+    scheduler::OneShotTimer mScreenUpdateTimer;
 };
 
 } // namespace impl