From c15d6657a17d7cef91f800f40d11760e2e7340af Mon Sep 17 00:00:00 2001
From: Glenn Kasten <gkasten@google.com>
Date: Wed, 30 May 2012 14:52:57 -0700
Subject: Add audio watchdog thread

Change-Id: I4ed62087bd6554179abb8258d2da606050e762c0
---
 services/audioflinger/AudioWatchdog.cpp | 134 ++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 services/audioflinger/AudioWatchdog.cpp

(limited to 'services/audioflinger/AudioWatchdog.cpp')

diff --git a/services/audioflinger/AudioWatchdog.cpp b/services/audioflinger/AudioWatchdog.cpp
new file mode 100644
index 0000000..8f328ee
--- /dev/null
+++ b/services/audioflinger/AudioWatchdog.cpp
@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#define LOG_TAG "AudioWatchdog"
+//#define LOG_NDEBUG 0
+
+#include <utils/Log.h>
+#include "AudioWatchdog.h"
+
+namespace android {
+
+void AudioWatchdogDump::dump(int fd)
+{
+    char buf[32];
+    if (mMostRecent != 0) {
+        // includes NUL terminator
+        ctime_r(&mMostRecent, buf);
+    } else {
+        strcpy(buf, "N/A\n");
+    }
+    fdprintf(fd, "Watchdog: underruns=%u, logs=%u, most recent underrun log at %s",
+            mUnderruns, mLogs, buf);
+}
+
+bool AudioWatchdog::threadLoop()
+{
+    {
+        AutoMutex _l(mMyLock);
+        if (mPaused) {
+            mMyCond.wait(mMyLock);
+            // ignore previous timestamp after resume()
+            mOldTsValid = false;
+            // force an immediate log on first underrun after resume()
+            mLogTs.tv_sec = MIN_TIME_BETWEEN_LOGS_SEC;
+            mLogTs.tv_nsec = 0;
+            // caller will check for exitPending()
+            return true;
+        }
+    }
+    struct timespec newTs;
+    int rc = clock_gettime(CLOCK_MONOTONIC, &newTs);
+    if (rc != 0) {
+        pause();
+        return false;
+    }
+    if (!mOldTsValid) {
+        mOldTs = newTs;
+        mOldTsValid = true;
+        return true;
+    }
+    time_t sec = newTs.tv_sec - mOldTs.tv_sec;
+    long nsec = newTs.tv_nsec - mOldTs.tv_nsec;
+    if (nsec < 0) {
+        --sec;
+        nsec += 1000000000;
+    }
+    mOldTs = newTs;
+    // cycleNs is same as sec*1e9 + nsec, but limited to about 4 seconds
+    uint32_t cycleNs = nsec;
+    if (sec > 0) {
+        if (sec < 4) {
+            cycleNs += sec * 1000000000;
+        } else {
+            cycleNs = 4000000000u;
+        }
+    }
+    mLogTs.tv_sec += sec;
+    if ((mLogTs.tv_nsec += nsec) >= 1000000000) {
+        mLogTs.tv_sec++;
+        mLogTs.tv_nsec -= 1000000000;
+    }
+    if (cycleNs > mMaxCycleNs) {
+        mDump->mUnderruns = ++mUnderruns;
+        if (mLogTs.tv_sec >= MIN_TIME_BETWEEN_LOGS_SEC) {
+            mDump->mLogs = ++mLogs;
+            mDump->mMostRecent = time(NULL);
+            ALOGW("Insufficient CPU for load: expected=%.1f actual=%.1f ms; underruns=%u logs=%u",
+                mPeriodNs * 1e-6, cycleNs * 1e-6, mUnderruns, mLogs);
+            mLogTs.tv_sec = 0;
+            mLogTs.tv_nsec = 0;
+        }
+    }
+    struct timespec req;
+    req.tv_sec = 0;
+    req.tv_nsec = mPeriodNs;
+    rc = nanosleep(&req, NULL);
+    if (!((rc == 0) || (rc == -1 && errno == EINTR))) {
+        pause();
+        return false;
+    }
+    return true;
+}
+
+void AudioWatchdog::requestExit()
+{
+    // must be in this order to avoid a race condition
+    Thread::requestExit();
+    resume();
+}
+
+void AudioWatchdog::pause()
+{
+    AutoMutex _l(mMyLock);
+    mPaused = true;
+}
+
+void AudioWatchdog::resume()
+{
+    AutoMutex _l(mMyLock);
+    if (mPaused) {
+        mPaused = false;
+        mMyCond.signal();
+    }
+}
+
+void AudioWatchdog::setDump(AudioWatchdogDump *dump)
+{
+    mDump = dump != NULL ? dump : &mDummyDump;
+}
+
+}   // namespace android
-- 
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