Package dalvik.system

Class VMDebug

  • public final class VMDebug
extends Object
    Provides access to some VM-specific debug features. Though this class and many of its members are public, this class is meant to be wrapped in a more friendly way for use by application developers. On the Android platform, the recommended way to access this functionality is through the class android.os.Debug.

    • Field Detail

      • TRACE_COUNT_ALLOCS

        public static final int TRACE_COUNT_ALLOCS
        flag for startMethodTracing(), which adds the results from startAllocCounting to the trace key file.
        See Also:
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      • KIND_GLOBAL_ALLOCATED_OBJECTS

        public static final int KIND_GLOBAL_ALLOCATED_OBJECTS
        See Also:
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      • KIND_GLOBAL_ALLOCATED_BYTES

        public static final int KIND_GLOBAL_ALLOCATED_BYTES
        See Also:
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      • KIND_GLOBAL_FREED_OBJECTS

        public static final int KIND_GLOBAL_FREED_OBJECTS
        See Also:
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      • KIND_GLOBAL_FREED_BYTES

        public static final int KIND_GLOBAL_FREED_BYTES
        See Also:
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      • KIND_GLOBAL_GC_INVOCATIONS

        public static final int KIND_GLOBAL_GC_INVOCATIONS
        See Also:
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      • KIND_GLOBAL_CLASS_INIT_COUNT

        public static final int KIND_GLOBAL_CLASS_INIT_COUNT
        See Also:
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      • KIND_GLOBAL_CLASS_INIT_TIME

        public static final int KIND_GLOBAL_CLASS_INIT_TIME
        See Also:
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      • KIND_GLOBAL_EXT_ALLOCATED_OBJECTS

        public static final int KIND_GLOBAL_EXT_ALLOCATED_OBJECTS
        See Also:
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      • KIND_GLOBAL_EXT_ALLOCATED_BYTES

        public static final int KIND_GLOBAL_EXT_ALLOCATED_BYTES
        See Also:
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      • KIND_GLOBAL_EXT_FREED_OBJECTS

        public static final int KIND_GLOBAL_EXT_FREED_OBJECTS
        See Also:
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      • KIND_GLOBAL_EXT_FREED_BYTES

        public static final int KIND_GLOBAL_EXT_FREED_BYTES
        See Also:
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      • KIND_THREAD_ALLOCATED_OBJECTS

        public static final int KIND_THREAD_ALLOCATED_OBJECTS
        See Also:
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      • KIND_THREAD_ALLOCATED_BYTES

        public static final int KIND_THREAD_ALLOCATED_BYTES
        See Also:
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      • KIND_THREAD_FREED_OBJECTS

        public static final int KIND_THREAD_FREED_OBJECTS
        See Also:
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      • KIND_THREAD_FREED_BYTES

        public static final int KIND_THREAD_FREED_BYTES
        See Also:
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      • KIND_THREAD_GC_INVOCATIONS

        public static final int KIND_THREAD_GC_INVOCATIONS
        See Also:
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      • KIND_THREAD_CLASS_INIT_COUNT

        public static final int KIND_THREAD_CLASS_INIT_COUNT
        See Also:
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      • KIND_THREAD_CLASS_INIT_TIME

        public static final int KIND_THREAD_CLASS_INIT_TIME
        See Also:
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      • KIND_THREAD_EXT_ALLOCATED_OBJECTS

        public static final int KIND_THREAD_EXT_ALLOCATED_OBJECTS
        See Also:
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      • KIND_THREAD_EXT_ALLOCATED_BYTES

        public static final int KIND_THREAD_EXT_ALLOCATED_BYTES
        See Also:
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      • KIND_THREAD_EXT_FREED_OBJECTS

        public static final int KIND_THREAD_EXT_FREED_OBJECTS
        See Also:
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      • KIND_THREAD_EXT_FREED_BYTES

        public static final int KIND_THREAD_EXT_FREED_BYTES
        See Also:
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    • Method Detail

      • lastDebuggerActivity

        public static long lastDebuggerActivity()
        Returns the time since the last known debugger activity.
        Returns:
        the time in milliseconds, or -1 if the debugger is not connected

      • isDebuggingEnabled

        public static boolean isDebuggingEnabled()
        Determines if debugging is enabled in this VM. If debugging is not enabled, a debugger cannot be attached.
        Returns:
        true if debugging is enabled

      • isDebuggerConnected

        public static boolean isDebuggerConnected()
        Determines if a debugger is currently attached.
        Returns:
        true if (and only if) a debugger is connected

      • getVmFeatureList

        public static String[] getVmFeatureList()
        Returns an array of strings that identify VM features. This is used by DDMS to determine what sorts of operations the VM can perform.

      • startMethodTracing

        @Deprecated
public static void startMethodTracing()
        Deprecated.
        Not used, not needed.
        Start method tracing with default name, size, and with 0 flags.

      • startMethodTracing

        public static void startMethodTracing​(String traceFileName,
                                      int bufferSize,
                                      int flags,
                                      boolean samplingEnabled,
                                      int intervalUs)
        Start method tracing, specifying a file name as well as a default buffer size. See Running the Traceview Debugging Program for information about reading trace files.

        You can use either a fully qualified path and name, or just a name. If only a name is specified, the file will be created under the /sdcard/ directory. If a name is not given, the default is /sdcard/dmtrace.trace.

        Parameters:
        traceFileName - name to give the trace file
        bufferSize - the maximum size of both files combined. If passed as 0, it defaults to 8MB.
        flags - flags to control method tracing. The only one that is currently defined is TRACE_COUNT_ALLOCS.
        samplingEnabled - if true, sample profiling is enabled. Otherwise, method instrumentation is used.
        intervalUs - the time between samples in microseconds when sampling is enabled.

      • startMethodTracing

        public static void startMethodTracing​(String traceFileName,
                                      FileDescriptor fd,
                                      int bufferSize,
                                      int flags,
                                      boolean samplingEnabled,
                                      int intervalUs)
        Like startMethodTracing(String, int, int), but taking an already-opened FileDescriptor in which the trace is written. The file name is also supplied simply for logging. Makes a dup of the file descriptor.

      • startMethodTracingDdms

        public static void startMethodTracingDdms​(int bufferSize,
                                          int flags,
                                          boolean samplingEnabled,
                                          int intervalUs)
        Starts method tracing without a backing file. When stopMethodTracing is called, the result is sent directly to DDMS. (If DDMS is not attached when tracing ends, the profiling data will be discarded.)

      • getMethodTracingMode

        public static int getMethodTracingMode()
        Determine whether method tracing is currently active and what type is active.

      • stopMethodTracing

        public static void stopMethodTracing()
        Stops method tracing.

      • startEmulatorTracing

        public static void startEmulatorTracing()
        Starts sending Dalvik method trace info to the emulator.

      • stopEmulatorTracing

        public static void stopEmulatorTracing()
        Stops sending Dalvik method trace info to the emulator.

      • threadCpuTimeNanos

        public static long threadCpuTimeNanos()
        Get an indication of thread CPU usage. The value returned indicates the amount of time that the current thread has spent executing code or waiting for certain types of I/O.

        The time is expressed in nanoseconds, and is only meaningful when compared to the result from an earlier call. Note that nanosecond resolution does not imply nanosecond accuracy.

        Returns:
        the CPU usage. A value of -1 means the system does not support this feature.

      • startAllocCounting

        public static void startAllocCounting()
        Count the number and aggregate size of memory allocations between two points.

      • stopAllocCounting

        public static void stopAllocCounting()

      • getAllocCount

        public static int getAllocCount​(int kind)

      • resetAllocCount

        public static void resetAllocCount​(int kinds)

      • setAllocationLimit

        @Deprecated
public static int setAllocationLimit​(int limit)
        Deprecated.
        This method exists for binary compatibility. It was part of the allocation limits API which was removed in Android 3.0 (Honeycomb).

      • setGlobalAllocationLimit

        @Deprecated
public static int setGlobalAllocationLimit​(int limit)
        Deprecated.
        This method exists for binary compatibility. It was part of the allocation limits API which was removed in Android 3.0 (Honeycomb).

      • startInstructionCounting

        public static void startInstructionCounting()
        Count the number of instructions executed between two points.

      • stopInstructionCounting

        public static void stopInstructionCounting()

      • getInstructionCount

        public static void getInstructionCount​(int[] counts)

      • resetInstructionCount

        public static void resetInstructionCount()

      • printLoadedClasses

        public static void printLoadedClasses​(int flags)
        Dumps a list of loaded class to the log file.

      • getLoadedClassCount

        public static int getLoadedClassCount()
        Gets the number of loaded classes.
        Returns:
        the number of loaded classes

      • dumpHprofData

        public static void dumpHprofData​(String filename)
                          throws IOException
        Dumps "hprof" data to the specified file. This may cause a GC. The VM may create a temporary file in the same directory.
        Parameters:
        filename - Full pathname of output file (e.g. "/sdcard/dump.hprof").
        Throws:
        UnsupportedOperationException - if the VM was built without HPROF support.
        IOException - if an error occurs while opening or writing files.

      • dumpHprofDataDdms

        public static void dumpHprofDataDdms()
        Collects "hprof" heap data and sends it to DDMS. This may cause a GC.
        Throws:
        UnsupportedOperationException - if the VM was built without HPROF support.

      • dumpHprofData

        public static void dumpHprofData​(String fileName,
                                 FileDescriptor fd)
                          throws IOException
        Dumps "hprof" heap data to a file, by name or descriptor.
        Parameters:
        fileName - Name of output file. If fd is non-null, the file name is only used in log messages (and may be null).
        fd - Descriptor of open file that will receive the output. If this is null, the fileName is used instead.
        Throws:
        IOException

      • cacheRegisterMap

        public static boolean cacheRegisterMap​(String classAndMethodDesc)
        Primes the register map cache.

      • dumpReferenceTables

        public static void dumpReferenceTables()
        Dumps the contents of the VM reference tables (e.g. JNI locals and globals) to the log file.

      • crash

        public static void crash()
        Crashes the VM. Seriously. Dumps the interpreter stack trace for the current thread and then aborts the VM so you can see the native stack trace. Useful for figuring out how you got somewhere when lots of native code is involved.

      • infopoint

        public static void infopoint​(int id)
        Together with gdb, provide a handy way to stop the VM at user-tagged locations.

      • countInstancesOfClass

        public static long countInstancesOfClass​(Class klass,
                                         boolean assignable)
        Counts the instances of a class. It is the caller's responsibility to do GC if they don't want unreachable objects to get counted.
        Parameters:
        klass - the class to be counted.
        assignable - if false, direct instances of klass are counted. If true, instances that are assignable to klass, as defined by Class.isAssignableFrom(java.lang.Class<?>) are counted.
        Returns:
        the number of matching instances.

      • countInstancesOfClasses

        public static long[] countInstancesOfClasses​(Class[] classes,
                                             boolean assignable)
        Counts the instances of classes. It is the caller's responsibility to do GC if they don't want unreachable objects to get counted.
        Parameters:
        classes - the classes to be counted.
        assignable - if false, direct instances of klass are counted. If true, instances that are assignable to klass, as defined by Class.isAssignableFrom(java.lang.Class<?>) are counted.
        Returns:
        an array containing the number of matching instances. The value for an index is the number of instances of the class at that index in number classes.

      • getHeapSpaceStats

        public static void getHeapSpaceStats​(long[] data)
        Export the heap per-space stats for dumpsys meminfo. The content of the array is: 
           data[0] : the application heap space size
   data[1] : the application heap space allocated bytes
   data[2] : the application heap space free bytes
   data[3] : the zygote heap space size
   data[4] : the zygote heap space allocated size
   data[5] : the zygote heap space free size
   data[6] : the large object space size
   data[7] : the large object space allocated bytes
   data[8] : the large object space free bytes
        Parameters:
        data - the array into which the stats are written.

      • getRuntimeStat

        public static String getRuntimeStat​(String statName)
        Returns the value of a particular runtime statistic or null if no such runtime statistic exists.
        Parameters:
        statName - the name of the runtime statistic to look up.
        Returns:
        the value of the runtime statistic.

      • getRuntimeStats

        public static Map<String,​String> getRuntimeStats()
        Returns a map of the names/values of the runtime statistics that #getRuntimeStat() supports.
        Returns:
        a map of the names/values of the supported runtime statistics.