Implement PressureStallInformation extraction logic. (5602d31f) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/stats/pull/psi/OWNERS

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		jackrichardson@google.com
		dbrotikovskaya@google.com
		ivokay@google.com
		gagapov@google.com
		yigitfiliz@google.com
		rswang@google.com
		evaleriano@google.com
		igorstepanov@google.com
		iyou@google.com

services/core/java/com/android/server/stats/pull/psi/PsiData.java

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		/*
		* Copyright (C) 2024 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package com.android.server.stats.pull.psi;

		/**
		* Wraps PSI (Pressure Stall Information) corresponding to a system resource. See more details about
		* PSI, see https://docs.kernel.org/accounting/psi.html#psi-pressure-stall-information.
		*/
		public class PsiData {
		public enum ResourceType {
		CPU,
		MEMORY,
		IO
		}

		static class AppsStallInfo {

		/** Past 10s average % of wasted CPU cycles when apps tasks are stalled on mResourceType.*/
		private final float mAvg10SecPercentage;

		/** Past 60s average % of wasted CPU cycles when apps tasks are stalled on mResourceType.*/
		private final float mAvg60SecPercentage;

		/** Past 300s average % of wasted CPU cycles when apps tasks are stalled on mResourceType.*/
		private final float mAvg300SecPercentage;

		/** Total number of microseconds that apps tasks are stalled on mResourceType.*/
		private final long mTotalUsec;

		AppsStallInfo(
		float avg10SecPercentage, float avg60SecPercentage,
		float avg300SecPercentage, long totalUsec) {
		mAvg10SecPercentage = avg10SecPercentage;
		mAvg60SecPercentage = avg60SecPercentage;
		mAvg300SecPercentage = avg300SecPercentage;
		mTotalUsec = totalUsec;
		}
		}

		/** The system resource type of this {@code PsiData}. */
		private final ResourceType mResourceType;

		/** Info on some tasks are stalled on mResourceType. */
		private final AppsStallInfo mSomeAppsStallInfo;

		/**
		* Info on all non-idle tasks are stalled on mResourceType. For the CPU ResourceType,
		* all fields will always be 0 as it's undefined.
		*/
		private final AppsStallInfo mFullAppsStallInfo;

		PsiData(
		ResourceType resourceType,
		AppsStallInfo someAppsStallInfo,
		AppsStallInfo fullAppsStallInfo) {
		mResourceType = resourceType;
		mSomeAppsStallInfo = someAppsStallInfo;
		mFullAppsStallInfo = fullAppsStallInfo;
		}

		public ResourceType getResourceType() {
		return mResourceType;
		}

		public float getSomeAvg10SecPercentage() {
		return mSomeAppsStallInfo.mAvg10SecPercentage; }

		public float getSomeAvg60SecPercentage() {
		return mSomeAppsStallInfo.mAvg60SecPercentage; }

		public float getSomeAvg300SecPercentage() {
		return mSomeAppsStallInfo.mAvg300SecPercentage; }

		public long getSomeTotalUsec() {
		return mSomeAppsStallInfo.mTotalUsec;
		}

		public float getFullAvg10SecPercentage() {
		return mFullAppsStallInfo.mAvg10SecPercentage;
		}

		public float getFullAvg60SecPercentage() {
		return mFullAppsStallInfo.mAvg60SecPercentage;
		}

		public float getFullAvg300SecPercentage() {
		return mFullAppsStallInfo.mAvg300SecPercentage; }

		public long getFullTotalUsec() {
		return mFullAppsStallInfo.mTotalUsec;
		}
		}

services/core/java/com/android/server/stats/pull/psi/PsiExtractor.java

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		/*
		* Copyright (C) 2024 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package com.android.server.stats.pull.psi;

		import static java.util.stream.Collectors.joining;

		import android.annotation.Nullable;
		import android.util.Log;

		import java.io.BufferedReader;
		import java.io.FileInputStream;
		import java.io.IOException;
		import java.io.InputStreamReader;
		import java.text.MessageFormat;
		import java.util.regex.Matcher;
		import java.util.regex.Pattern;

		public class PsiExtractor {
		private static final String TAG = "PsiExtractor";

		// Paths for PSI files are guarded by SELinux policy. PCS needs to be explicitly
		// allowlisted to access these files.
		private static final String PSI_MEMORY_PATH = "/proc/pressure/memory";
		private static final String PSI_IO_PATH = "/proc/pressure/io";
		private static final String PSI_CPU_PATH = "/proc/pressure/cpu";

		// The patterns matching a line of PSI output such as
		// "some avg10=0.12 avg60=0.34 avg300=0.56 total=123456" or
		// "full avg10=0.12 avg60=0.34 avg300=0.56 total=123456" to extract the stalling percentage
		// values for "some" and "full" line of PSI output respectively.
		private static final String PSI_PATTERN_TEMPLATE =
		".{0} avg10=(\\d+.\\d+) avg60=(\\d+.\\d+) avg300=(\\d+.\\d+) total=(\\d+).";
		private static final String SOME = "some";
		private static final String FULL = "full";
		private final PsiReader mPsiReader;

		public PsiExtractor() {
		mPsiReader = new PsiReader();
		}
		public PsiExtractor(PsiReader psiReader) {
		mPsiReader = psiReader;
		}

		/**
		* Parses /pressure/proc/{resourceType} kernel file to extract the Pressure Stall Information
		* (PSI), more information: can be found at https://docs.kernel.org/accounting/psi.html.
		*
		* @param resourceType (Memory/CPU/IO) to get the PSI for.
		*/
		@Nullable
		public PsiData getPsiData(PsiData.ResourceType resourceType) {
		String psiFileData;
		if (resourceType == PsiData.ResourceType.MEMORY) {
		psiFileData = mPsiReader.read(PSI_MEMORY_PATH);
		} else if (resourceType == PsiData.ResourceType.IO) {
		psiFileData = mPsiReader.read(PSI_IO_PATH);
		} else if (resourceType == PsiData.ResourceType.CPU) {
		psiFileData = mPsiReader.read(PSI_CPU_PATH);
		} else {
		Log.w(TAG, "PsiExtractor failure: cannot read kernel source file, returning null");
		return null;
		}
		return parsePsiData(psiFileData, resourceType);
		}

		@Nullable
		private static PsiData.AppsStallInfo parsePsiString(
		String psiFileData, String appType, PsiData.ResourceType resourceType) {
		// There is an extra case of file content: the CPU full is undefined and isn't reported for
		// earlier versions. It should be always propagated as 0, but for the current logic purposes
		// we will report atom only if at least one value (some/full) is presented. Thus, hardcoding
		// the "full" line as 0 only when the "some" line is presented.
		if (appType == FULL && resourceType == PsiData.ResourceType.CPU) {
		if (psiFileData.contains(SOME) && !psiFileData.contains(FULL)) {
		return new PsiData.AppsStallInfo((float) 0.0, (float) 0.0, (float) 0.0, 0);
		}
		}

		Pattern psiStringPattern = Pattern.compile(
		MessageFormat.format(PSI_PATTERN_TEMPLATE, appType));
		Matcher psiLineMatcher = psiStringPattern.matcher(psiFileData);

		// Parsing the line starts with "some" in the expected output.
		// The line for "some" should always be present in PSI output. The output must be somehow
		// malformed if the line cannot be matched.
		if (!psiLineMatcher.find()) {
		Log.w(TAG,
		"Returning null: the line \"" + appType + "\" is not in expected pattern.");
		return null;
		}
		try {
		return new PsiData.AppsStallInfo(
		Float.parseFloat(psiLineMatcher.group(1)),
		Float.parseFloat(psiLineMatcher.group(2)),
		Float.parseFloat(psiLineMatcher.group(3)),
		Long.parseLong(psiLineMatcher.group(4)));
		} catch (NumberFormatException e) {
		Log.w(TAG,
		"Returning null: some value in line \"" + appType
		+ "\" cannot be parsed as numeric.");
		return null;
		}
		}

		@Nullable
		private static PsiData parsePsiData(
		String psiFileData, PsiData.ResourceType resourceType) {
		PsiData.AppsStallInfo someAppsStallInfo = parsePsiString(psiFileData, SOME, resourceType);
		PsiData.AppsStallInfo fullAppsStallInfo = parsePsiString(psiFileData, FULL, resourceType);

		if (someAppsStallInfo == null && fullAppsStallInfo == null) {
		Log.w(TAG, "Returning empty PSI: some or full line are failed to parse");
		return null;
		} else if (someAppsStallInfo == null) {
		Log.d(TAG, "Replacing some info with empty PSI record for the resource type "
		+ resourceType);
		someAppsStallInfo = new PsiData.AppsStallInfo(
		(float) -1.0, (float) -1.0, (float) -1.0, -1);
		} else if (fullAppsStallInfo == null) {
		Log.d(TAG, "Replacing full info with empty PSI record for the resource type "
		+ resourceType);
		fullAppsStallInfo = new PsiData.AppsStallInfo(
		(float) -1.0, (float) -1.0, (float) -1.0, -1);
		}
		return new PsiData(resourceType, someAppsStallInfo, fullAppsStallInfo);
		}

		/** Dependency class */
		public static class PsiReader {
		/**
		* Reads file from provided path and returns its content if the file found, null otherwise.
		*
		* @param filePath file path to read.
		*/
		@Nullable
		public String read(String filePath) {
		try (BufferedReader br =
		new BufferedReader(new InputStreamReader(
		new FileInputStream(filePath)))) {
		return br.lines().collect(joining(System.lineSeparator()));
		} catch (IOException e) {
		Log.w(TAG, "Cannot read file " + filePath);
		return null;
		}
		}
		}
		}

services/tests/servicestests/src/com/android/server/stats/pull/psi/OWNERS

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		include /services/core/java/com/android/server/stats/pull/psi/OWNERS

services/tests/servicestests/src/com/android/server/stats/pull/psi/PsiExtractorTest.java

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