f6e2296953
logd suffers performance degradation when multiple blocking
readers connect to it. Each time when the writer thread log
new entries, all of the readers are notified regardless of
which log id they are watching.
In this case, only give notification to the readers who are
actually watching new entries' log id. This decreases logd
CPU consumption by skipping unnecessary LogBuffer::flushTo
loops.
Test: liblog-unit-tests, logd-unit-tests & CtsLiblogTestCases
logcat-unit-tests
Test: manual:
1.'logcat –b all' at constant heavy logging load level
2.simultaneously 'logcat –b crash' in another session,
a healthy crash buffer usually keep empty
3.logd CPU consumption doesn't increase after step 2
Change-Id: I4ffc045c9feb7a0998f7e47ae2173f8f6aa28e8a
104 lines
3.4 KiB
C++
Executable file
104 lines
3.4 KiB
C++
Executable file
/*
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* Copyright (C) 2012-2014 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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#include <stdlib.h>
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#include <private/android_filesystem_config.h>
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#include "FlushCommand.h"
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#include "LogBuffer.h"
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#include "LogBufferElement.h"
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#include "LogCommand.h"
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#include "LogReader.h"
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#include "LogTimes.h"
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#include "LogUtils.h"
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// runSocketCommand is called once for every open client on the
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// log reader socket. Here we manage and associated the reader
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// client tracking and log region locks LastLogTimes list of
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// LogTimeEntrys, and spawn a transitory per-client thread to
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// work at filing data to the socket.
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//
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// global LogTimeEntry::wrlock() is used to protect access,
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// reference counts are used to ensure that individual
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// LogTimeEntry lifetime is managed when not protected.
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void FlushCommand::runSocketCommand(SocketClient* client) {
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LogTimeEntry* entry = NULL;
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LastLogTimes& times = mReader.logbuf().mTimes;
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LogTimeEntry::wrlock();
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LastLogTimes::iterator it = times.begin();
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while (it != times.end()) {
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entry = (*it);
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if (entry->mClient == client) {
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if (!entry->isWatchingMultiple(mLogMask)) {
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LogTimeEntry::unlock();
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return;
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}
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if (entry->mTimeout.tv_sec || entry->mTimeout.tv_nsec) {
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if (mReader.logbuf().isMonotonic()) {
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LogTimeEntry::unlock();
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return;
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}
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// If the user changes the time in a gross manner that
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// invalidates the timeout, fall through and trigger.
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log_time now(CLOCK_REALTIME);
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if (((entry->mEnd + entry->mTimeout) > now) &&
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(now > entry->mEnd)) {
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LogTimeEntry::unlock();
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return;
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}
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}
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entry->triggerReader_Locked();
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if (entry->runningReader_Locked()) {
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LogTimeEntry::unlock();
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return;
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}
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entry->incRef_Locked();
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break;
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}
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it++;
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}
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if (it == times.end()) {
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// Create LogTimeEntry in notifyNewLog() ?
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if (mTail == (unsigned long)-1) {
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LogTimeEntry::unlock();
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return;
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}
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entry = new LogTimeEntry(mReader, client, mNonBlock, mTail, mLogMask,
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mPid, mStart, mTimeout);
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times.push_front(entry);
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}
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client->incRef();
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// release client and entry reference counts once done
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entry->startReader_Locked();
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LogTimeEntry::unlock();
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}
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bool FlushCommand::hasReadLogs(SocketClient* client) {
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return clientHasLogCredentials(client);
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}
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static bool clientHasSecurityCredentials(SocketClient* client) {
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return (client->getUid() == AID_SYSTEM) || (client->getGid() == AID_SYSTEM);
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}
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bool FlushCommand::hasSecurityLogs(SocketClient* client) {
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return clientHasSecurityCredentials(client);
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}
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