From b3b5a766bb0d35ceb0f10cefc15047bce1fd64cc Mon Sep 17 00:00:00 2001 From: Wessam Hassanein Date: Thu, 9 Mar 2023 01:56:04 +0000 Subject: Improve Transition GC initiation by improving the Frameworks triggering signal Transition GC should be initiated when the app status transitions into the cached state from a non-cached state. Test: Local testing Bug: 272381448 Change-Id: I483a3ddaa11ed037d32c5481999fd996e2e2629a --- core/java/android/app/ActivityThread.java | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/core/java/android/app/ActivityThread.java b/core/java/android/app/ActivityThread.java index e709a1ac2d36..30a2303a5e41 100644 --- a/core/java/android/app/ActivityThread.java +++ b/core/java/android/app/ActivityThread.java @@ -3434,8 +3434,13 @@ public final class ActivityThread extends ClientTransactionHandler if (mLastProcessState == processState) { return; } + // Do not issue a transitional GC if we are transitioning between 2 cached states. + // Only update if the state flips between cached and uncached or vice versa + if (ActivityManager.isProcStateCached(mLastProcessState) + != ActivityManager.isProcStateCached(processState)) { + updateVmProcessState(processState); + } mLastProcessState = processState; - updateVmProcessState(processState); if (localLOGV) { Slog.i(TAG, "******************* PROCESS STATE CHANGED TO: " + processState + (fromIpc ? " (from ipc" : "")); @@ -3444,12 +3449,16 @@ public final class ActivityThread extends ClientTransactionHandler } /** Update VM state based on ActivityManager.PROCESS_STATE_* constants. */ + // Currently ART VM only uses state updates for Transitional GC, and thus + // this function initiates a Transitional GC for transitions into Cached apps states. private void updateVmProcessState(int processState) { - // TODO: Tune this since things like gmail sync are important background but not jank - // perceptible. - final int state = processState <= ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND - ? VM_PROCESS_STATE_JANK_PERCEPTIBLE - : VM_PROCESS_STATE_JANK_IMPERCEPTIBLE; + // Only a transition into Cached state should result in a Transitional GC request + // to the ART runtime. Update VM state to JANK_IMPERCEPTIBLE in that case. + // Note that there are 4 possible cached states currently, all of which are + // JANK_IMPERCEPTIBLE from GC point of view. + final int state = ActivityManager.isProcStateCached(processState) + ? VM_PROCESS_STATE_JANK_IMPERCEPTIBLE + : VM_PROCESS_STATE_JANK_PERCEPTIBLE; VMRuntime.getRuntime().updateProcessState(state); } -- cgit v1.2.3-59-g8ed1b