/*
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* Copyright 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.server.wifi;
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import android.content.Context;
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import android.provider.Settings;
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import com.android.server.wifi.nano.WifiMetricsProto.WifiIsUnusableEvent;
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/**
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* Looks for Wifi data stalls
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*/
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public class WifiDataStall {
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// Default minimum number of txBadDelta to trigger data stall
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public static final int MIN_TX_BAD_DEFAULT = 1;
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// Default minimum number of txSuccessDelta to trigger data stall
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// when rxSuccessDelta is 0
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public static final int MIN_TX_SUCCESS_WITHOUT_RX_DEFAULT = 50;
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// Maximum time gap between two WifiLinkLayerStats to trigger a data stall
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public static final long MAX_MS_DELTA_FOR_DATA_STALL = 60 * 1000; // 1 minute
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private final Context mContext;
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private final FrameworkFacade mFacade;
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private final WifiMetrics mWifiMetrics;
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private int mMinTxBad;
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private int mMinTxSuccessWithoutRx;
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public WifiDataStall(Context context, FrameworkFacade facade, WifiMetrics wifiMetrics) {
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mContext = context;
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mFacade = facade;
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mWifiMetrics = wifiMetrics;
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loadSettings();
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}
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/**
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* Load setting values related to wifi data stall.
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*/
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public void loadSettings() {
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mMinTxBad = mFacade.getIntegerSetting(
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mContext, Settings.Global.WIFI_DATA_STALL_MIN_TX_BAD, MIN_TX_BAD_DEFAULT);
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mMinTxSuccessWithoutRx = mFacade.getIntegerSetting(
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mContext, Settings.Global.WIFI_DATA_STALL_MIN_TX_SUCCESS_WITHOUT_RX,
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MIN_TX_SUCCESS_WITHOUT_RX_DEFAULT);
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mWifiMetrics.setWifiDataStallMinTxBad(mMinTxBad);
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mWifiMetrics.setWifiDataStallMinRxWithoutTx(mMinTxSuccessWithoutRx);
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}
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/**
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* Checks for data stall by looking at tx/rx packet counts
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* @param oldStats second most recent WifiLinkLayerStats
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* @param newStats most recent WifiLinkLayerStats
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* @return trigger type of WifiIsUnusableEvent
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*/
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public int checkForDataStall(WifiLinkLayerStats oldStats, WifiLinkLayerStats newStats) {
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if (oldStats == null || newStats == null) {
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mWifiMetrics.resetWifiIsUnusableLinkLayerStats();
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return WifiIsUnusableEvent.TYPE_UNKNOWN;
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}
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long txSuccessDelta = (newStats.txmpdu_be + newStats.txmpdu_bk
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+ newStats.txmpdu_vi + newStats.txmpdu_vo)
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- (oldStats.txmpdu_be + oldStats.txmpdu_bk
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+ oldStats.txmpdu_vi + oldStats.txmpdu_vo);
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long txRetriesDelta = (newStats.retries_be + newStats.retries_bk
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+ newStats.retries_vi + newStats.retries_vo)
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- (oldStats.retries_be + oldStats.retries_bk
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+ oldStats.retries_vi + oldStats.retries_vo);
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long txBadDelta = (newStats.lostmpdu_be + newStats.lostmpdu_bk
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+ newStats.lostmpdu_vi + newStats.lostmpdu_vo)
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- (oldStats.lostmpdu_be + oldStats.lostmpdu_bk
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+ oldStats.lostmpdu_vi + oldStats.lostmpdu_vo);
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long rxSuccessDelta = (newStats.rxmpdu_be + newStats.rxmpdu_bk
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+ newStats.rxmpdu_vi + newStats.rxmpdu_vo)
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- (oldStats.rxmpdu_be + oldStats.rxmpdu_bk
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+ oldStats.rxmpdu_vi + oldStats.rxmpdu_vo);
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long timeMsDelta = newStats.timeStampInMs - oldStats.timeStampInMs;
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if (timeMsDelta < 0
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|| txSuccessDelta < 0
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|| txRetriesDelta < 0
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|| txBadDelta < 0
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|| rxSuccessDelta < 0) {
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// There was a reset in WifiLinkLayerStats
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mWifiMetrics.resetWifiIsUnusableLinkLayerStats();
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return WifiIsUnusableEvent.TYPE_UNKNOWN;
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}
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mWifiMetrics.updateWifiIsUnusableLinkLayerStats(txSuccessDelta, txRetriesDelta,
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txBadDelta, rxSuccessDelta, timeMsDelta);
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if (timeMsDelta < MAX_MS_DELTA_FOR_DATA_STALL) {
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// There is a data stall if there are too many tx failures
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// or if we are not receiving any packets despite many tx successes
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boolean dataStallBadTx = (txBadDelta >= mMinTxBad);
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boolean dataStallTxSuccessWithoutRx =
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(rxSuccessDelta == 0 && txSuccessDelta >= mMinTxSuccessWithoutRx);
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if (dataStallBadTx && dataStallTxSuccessWithoutRx) {
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mWifiMetrics.logWifiIsUnusableEvent(WifiIsUnusableEvent.TYPE_DATA_STALL_BOTH);
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return WifiIsUnusableEvent.TYPE_DATA_STALL_BOTH;
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} else if (dataStallBadTx) {
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mWifiMetrics.logWifiIsUnusableEvent(WifiIsUnusableEvent.TYPE_DATA_STALL_BAD_TX);
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return WifiIsUnusableEvent.TYPE_DATA_STALL_BAD_TX;
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} else if (dataStallTxSuccessWithoutRx) {
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mWifiMetrics.logWifiIsUnusableEvent(
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WifiIsUnusableEvent.TYPE_DATA_STALL_TX_WITHOUT_RX);
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return WifiIsUnusableEvent.TYPE_DATA_STALL_TX_WITHOUT_RX;
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}
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}
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return WifiIsUnusableEvent.TYPE_UNKNOWN;
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}
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}
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