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Commit f6e22969 authored by Hao Wang's avatar Hao Wang Committed by liuchao
Browse files

logd: enhance multiple blocking readers performance 

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
parent ebca57ad

logd/FlushCommand.cpp

100644 → 100755
+4 −12
Original line number Diff line number Diff line
@@ -26,18 +26,6 @@ 
#include "LogTimes.h"

#include "LogUtils.h"



FlushCommand::FlushCommand(LogReader& reader, bool nonBlock, unsigned long tail,

                           unsigned int logMask, pid_t pid, log_time start,

                           uint64_t timeout)

    : mReader(reader),

      mNonBlock(nonBlock),

      mTail(tail),

      mLogMask(logMask),

      mPid(pid),

      mStart(start),

      mTimeout((start != log_time::EPOCH) ? timeout : 0) {

}



// runSocketCommand is called once for every open client on the

// log reader socket. Here we manage and associated the reader

// client tracking and log region locks LastLogTimes list of
@@ -56,6 +44,10 @@ void FlushCommand::runSocketCommand(SocketClient* client) { 
    while (it != times.end()) {

        entry = (*it);

        if (entry->mClient == client) {

            if (!entry->isWatchingMultiple(mLogMask)) {

                LogTimeEntry::unlock();

                return;

            }

            if (entry->mTimeout.tv_sec || entry->mTimeout.tv_nsec) {

                if (mReader.logbuf().isMonotonic()) {

                    LogTimeEntry::unlock();

logd/FlushCommand.h

100644 → 100755
+25 −5
Original line number Diff line number Diff line
@@ -29,16 +29,36 @@ class FlushCommand : public SocketClientCommand { 
    LogReader& mReader;

    bool mNonBlock;

    unsigned long mTail;

    unsigned int mLogMask;

    log_mask_t mLogMask;

    pid_t mPid;

    log_time mStart;

    uint64_t mTimeout;



   public:

    explicit FlushCommand(LogReader& mReader, bool nonBlock = false,

                          unsigned long tail = -1, unsigned int logMask = -1,

                          pid_t pid = 0, log_time start = log_time::EPOCH,

                          uint64_t timeout = 0);

    // for opening a reader

    explicit FlushCommand(LogReader& reader, bool nonBlock, unsigned long tail,

                          log_mask_t logMask, pid_t pid, log_time start,

                          uint64_t timeout)

        : mReader(reader),

          mNonBlock(nonBlock),

          mTail(tail),

          mLogMask(logMask),

          mPid(pid),

          mStart(start),

          mTimeout((start != log_time::EPOCH) ? timeout : 0) {

    }



    // for notification of an update

    explicit FlushCommand(LogReader& reader, log_mask_t logMask)

        : mReader(reader),

          mNonBlock(false),

          mTail(-1),

          mLogMask(logMask),

          mPid(0),

          mStart(log_time::EPOCH),

          mTimeout(0) {

    }



    virtual void runSocketCommand(SocketClient* client);



    static bool hasReadLogs(SocketClient* client);

logd/LogAudit.cpp

100644 → 100755
+4 −4
Original line number Diff line number Diff line
@@ -365,7 +365,7 @@ int LogAudit::logPrint(const char* fmt, ...) { 
                  : LOGGER_ENTRY_MAX_PAYLOAD;

    size_t message_len = str_len + sizeof(android_log_event_string_t);



    bool notify = false;

    log_mask_t notify = 0;



    if (events) {  // begin scope for event buffer

        uint32_t buffer[(message_len + sizeof(uint32_t) - 1) / sizeof(uint32_t)];
@@ -384,7 +384,7 @@ int LogAudit::logPrint(const char* fmt, ...) { 
            (message_len <= USHRT_MAX) ? (unsigned short)message_len

                                       : USHRT_MAX);

        if (rc >= 0) {

            notify = true;

            notify |= 1 << LOG_ID_EVENTS;

        }

        // end scope for event buffer

    }
@@ -440,7 +440,7 @@ int LogAudit::logPrint(const char* fmt, ...) { 
                                                    : USHRT_MAX);



        if (rc >= 0) {

            notify = true;

            notify |= 1 << LOG_ID_MAIN;

        }

        // end scope for main buffer

    }
@@ -449,7 +449,7 @@ int LogAudit::logPrint(const char* fmt, ...) { 
    free(str);



    if (notify) {

        reader->notifyNewLog();

        reader->notifyNewLog(notify);

        if (rc < 0) {

            rc = message_len;

        }

logd/LogKlog.cpp

100644 → 100755
+1 −1
Original line number Diff line number Diff line
@@ -826,7 +826,7 @@ int LogKlog::log(const char* buf, ssize_t len) { 


    // notify readers

    if (!rc) {

        reader->notifyNewLog();

        reader->notifyNewLog(static_cast<log_mask_t>(1 << LOG_ID_KERNEL));

    }



    return rc;

logd/LogListener.cpp

100644 → 100755
+6 −6
Original line number Diff line number Diff line
@@ -94,12 +94,13 @@ bool LogListener::onDataAvailable(SocketClient* cli) { 


    android_log_header_t* header =

        reinterpret_cast<android_log_header_t*>(buffer);

    if (/* header->id < LOG_ID_MIN || */ header->id >= LOG_ID_MAX ||

        header->id == LOG_ID_KERNEL) {

    log_id_t logId = static_cast<log_id_t>(header->id);

    if (/* logId < LOG_ID_MIN || */ logId >= LOG_ID_MAX ||

        logId == LOG_ID_KERNEL) {

        return false;

    }



    if ((header->id == LOG_ID_SECURITY) &&

    if ((logId == LOG_ID_SECURITY) &&

        (!__android_log_security() ||

         !clientHasLogCredentials(cred->uid, cred->gid, cred->pid))) {

        return false;
@@ -134,11 +135,10 @@ bool LogListener::onDataAvailable(SocketClient* cli) { 


    if (logbuf != nullptr) {

        int res = logbuf->log(

            (log_id_t)header->id, header->realtime, cred->uid, cred->pid,

            header->tid, msg,

            logId, header->realtime, cred->uid, cred->pid, header->tid, msg,

            ((size_t)n <= USHRT_MAX) ? (unsigned short)n : USHRT_MAX);

        if (res > 0 && reader != nullptr) {

            reader->notifyNewLog();

            reader->notifyNewLog(static_cast<log_mask_t>(1 << logId));

        }

    }