Added in API level 1

Debug


class Debug
kotlin.Any
   ↳ android.os.Debug

Provides various debugging methods for Android applications, including tracing and allocation counts.

Logging Trace Files

Debug can create log files that give details about an application, such as a call stack and start/stop times for any running methods. See Inspect Trace Logs with Traceview for information about reading trace files. To start logging trace files, call one of the startMethodTracing() methods. To stop tracing, call stopMethodTracing().

Summary

Nested classes

API for gathering and querying instruction counts.

This class is used to retrieved various statistics about the memory mappings for this process.

Constants
static Int

static Int

Flags for printLoadedClasses().

static Int

static Int

Flags for startMethodTracing().

Public methods
static Unit
attachJvmtiAgent(library: String, options: String?, classLoader: ClassLoader?)

Attach a library as a jvmti agent to the current runtime, with the given classloader determining the library search path.

static Unit

Change the JDWP port.

static Unit
dumpHprofData(fileName: String!)

Dump "hprof" data to the specified file.

static Boolean
dumpService(name: String!, fd: FileDescriptor!, args: Array<String!>!)

Get a debugging dump of a system service by name.

static Unit

Enable "emulator traces", in which information about the current method is made available to the "emulator -trace" feature.

static Int

Returns the number of death notification links to Binder objects that exist in the current process.

static Int

Returns the number of active local Binder objects that exist in the current process.

static Int

Returns the number of references to remote proxy Binder objects that exist in the current process.

static Int

Returns the number of received transactions from the binder driver.

static Int

Returns the number of sent transactions from this process.

static Int

Returns the global count of objects allocated by the runtime between a start and stop.

static Int

Returns the global size, in bytes, of objects allocated by the runtime between a start and stop.

static Int

Returns the number of classes successfully initialized (ie those that executed without throwing an exception) between a start and stop.

static Int

Returns the time spent successfully initializing classes between a start and stop.

static Int

This method exists for compatibility and always returns 0.

static Int

This method exists for compatibility and always returns 0.

static Int

This method exists for compatibility and always returns 0.

static Int

This method exists for compatibility and has no effect.

static Int

Returns the global count of objects freed by the runtime between a start and stop.

static Int

Returns the global size, in bytes, of objects freed by the runtime between a start and stop.

static Int

Returns the number of non-concurrent GC invocations between a start and stop.

static Int

Get the number of loaded classes.

static Unit

Retrieves information about this processes memory usages.

static Long

Returns the amount of allocated memory in the native heap.

static Long

Returns the amount of free memory in the native heap.

static Long

Returns the size of the native heap.

static Long

Retrieves the PSS memory used by the process as given by the smaps.

static Long

Retrieves the RSS memory used by the process as given by the status file.

static String!
getRuntimeStat(statName: String!)

Returns the value of a particular runtime statistic or null if no such runtime statistic exists.

static MutableMap<String!, String!>!

Returns a map of the names/values of the runtime statistics that getRuntimeStat(java.lang.String) supports.

static Int

Returns the thread-local count of objects allocated by the runtime between a start and stop.

static Int

Returns the thread-local size of objects allocated by the runtime between a start and stop.

static Int

This method exists for compatibility and has no effect.

static Int

This method exists for compatibility and has no effect.

static Int

Returns the number of thread-local non-concurrent GC invocations between a start and stop.

static Boolean

Determine if a debugger is currently attached.

static Unit

Dump a list of all currently loaded class to the log file.

static Unit

Clears all the global and thread-local memory allocation counters.

static Unit

Clears the global count of objects allocated.

static Unit

Clears the global size of objects allocated.

static Unit

Clears the count of classes initialized.

static Unit

Clears the count of time spent initializing classes.

static Unit

This method exists for compatibility and has no effect.

static Unit

This method exists for compatibility and has no effect.

static Unit

This method exists for compatibility and has no effect.

static Unit

This method exists for compatibility and has no effect.

static Unit

Clears the global count of objects freed.

static Unit

Clears the global size of objects freed.

static Unit

Clears the count of non-concurrent GC invocations.

static Unit

Clears the thread-local count of objects allocated.

static Unit

Clears the thread-local count of objects allocated.

static Unit

This method exists for compatibility and has no effect.

static Unit

This method exists for compatibility and has no effect.

static Unit

Clears the thread-local count of non-concurrent GC invocations.

static Int

Establish an object allocation limit in the current thread.

static Int

Establish a global object allocation limit.

static Unit

Start counting the number and aggregate size of memory allocations.

static Unit

Start method tracing with default log name and buffer size.

static Unit

Start method tracing, specifying the trace log file path.

static Unit
startMethodTracing(tracePath: String!, bufferSize: Int)

Start method tracing, specifying the trace log file name and the buffer size.

static Unit
startMethodTracing(tracePath: String!, bufferSize: Int, flags: Int)

Start method tracing, specifying the trace log file name, the buffer size, and flags.

static Unit
startMethodTracingSampling(tracePath: String!, bufferSize: Int, intervalUs: Int)

Start sampling-based method tracing, specifying the trace log file name, the buffer size, and the sampling interval.

static Unit

Enable qemu tracing.

static Unit

Stop counting the number and aggregate size of memory allocations.

static Unit

Stop method tracing.

static Unit

Stop qemu tracing.

static Long

Get an indication of thread CPU usage.

static Unit

Wait until a debugger attaches.

static Boolean

Returns "true" if one or more threads is waiting for a debugger to attach.

Constants

SHOW_CLASSLOADER

Added in API level 1
static val SHOW_CLASSLOADER: Int
Value: 2

SHOW_FULL_DETAIL

Added in API level 1
static val SHOW_FULL_DETAIL: Int

Flags for printLoadedClasses(). Default behavior is to only show the class name.

Value: 1

SHOW_INITIALIZED

Added in API level 1
static val SHOW_INITIALIZED: Int
Value: 4

TRACE_COUNT_ALLOCS

Added in API level 1
Deprecated in API level 23
static val TRACE_COUNT_ALLOCS: Int

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Flags for startMethodTracing(). These can be ORed together. TRACE_COUNT_ALLOCS adds the results from startAllocCounting to the trace key file.

Value: 1

Public methods

attachJvmtiAgent

Added in API level 28
static fun attachJvmtiAgent(
    library: String,
    options: String?,
    classLoader: ClassLoader?
): Unit

Attach a library as a jvmti agent to the current runtime, with the given classloader determining the library search path.

Note: agents may only be attached to debuggable apps. Otherwise, this function will throw a SecurityException.

Parameters
library String: the library containing the agent. This value cannot be null.
options String?: the options passed to the agent. This value may be null.
classLoader ClassLoader?: the classloader determining the library search path. This value may be null.
Exceptions
java.io.IOException if the agent could not be attached.
java.lang.SecurityException if the app is not debuggable.

changeDebugPort

Added in API level 1
Deprecated in API level 15
static fun changeDebugPort(port: Int): Unit

Deprecated: no longer needed or useful

Change the JDWP port.

dumpHprofData

Added in API level 3
static fun dumpHprofData(fileName: String!): Unit

Dump "hprof" data to the specified file. This may cause a GC.

Parameters
fileName String!: Full pathname of output file (e.g. "/sdcard/dump.hprof").
Exceptions
java.lang.UnsupportedOperationException if the VM was built without HPROF support.
java.io.IOException if an error occurs while opening or writing files.

dumpService

Added in API level 8
static fun dumpService(
    name: String!,
    fd: FileDescriptor!,
    args: Array<String!>!
): Boolean

Get a debugging dump of a system service by name.

Most services require the caller to hold android.permission.DUMP.

Parameters
name String!: of the service to dump
fd FileDescriptor!: to write dump output to (usually an output log file)
args Array<String!>!: to pass to the service's dump method, may be null
Return
Boolean true if the service was dumped successfully, false if the service could not be found or had an error while dumping

enableEmulatorTraceOutput

Added in API level 1
Deprecated in API level 34
static fun enableEmulatorTraceOutput(): Unit

Deprecated: Please use other tracing method in this class.

Enable "emulator traces", in which information about the current method is made available to the "emulator -trace" feature. There is no corresponding "disable" call -- this is intended for use by the framework when tracing should be turned on and left that way, so that traces captured with F9/F10 will include the necessary data. This puts the VM into "profile" mode, which has performance consequences. To temporarily enable tracing, use startNativeTracing().

getBinderDeathObjectCount

Added in API level 1
static fun getBinderDeathObjectCount(): Int

Returns the number of death notification links to Binder objects that exist in the current process.

getBinderLocalObjectCount

Added in API level 1
static fun getBinderLocalObjectCount(): Int

Returns the number of active local Binder objects that exist in the current process.

getBinderProxyObjectCount

Added in API level 1
static fun getBinderProxyObjectCount(): Int

Returns the number of references to remote proxy Binder objects that exist in the current process.

getBinderReceivedTransactions

Added in API level 1
static fun getBinderReceivedTransactions(): Int

Returns the number of received transactions from the binder driver.

Return
Int The number of received transactions or -1 if it could not read the stats.

getBinderSentTransactions

Added in API level 1
static fun getBinderSentTransactions(): Int

Returns the number of sent transactions from this process.

Return
Int The number of sent transactions or -1 if it could not read t.

getGlobalAllocCount

Added in API level 1
Deprecated in API level 23
static fun getGlobalAllocCount(): Int

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Returns the global count of objects allocated by the runtime between a start and stop.

getGlobalAllocSize

Added in API level 1
Deprecated in API level 23
static fun getGlobalAllocSize(): Int

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Returns the global size, in bytes, of objects allocated by the runtime between a start and stop.

getGlobalClassInitCount

Added in API level 8
Deprecated in API level 23
static fun getGlobalClassInitCount(): Int

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Returns the number of classes successfully initialized (ie those that executed without throwing an exception) between a start and stop.

getGlobalClassInitTime

Added in API level 8
Deprecated in API level 23
static fun getGlobalClassInitTime(): Int

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Returns the time spent successfully initializing classes between a start and stop.

getGlobalExternalAllocCount

Added in API level 1
Deprecated in API level 15
static fun getGlobalExternalAllocCount(): Int

Deprecated: This method is now obsolete.

This method exists for compatibility and always returns 0.

getGlobalExternalAllocSize

Added in API level 1
Deprecated in API level 15
static fun getGlobalExternalAllocSize(): Int

Deprecated: This method is now obsolete.

This method exists for compatibility and always returns 0.

getGlobalExternalFreedCount

Added in API level 1
Deprecated in API level 15
static fun getGlobalExternalFreedCount(): Int

Deprecated: This method is now obsolete.

This method exists for compatibility and always returns 0.

getGlobalExternalFreedSize

Added in API level 1
Deprecated in API level 15
static fun getGlobalExternalFreedSize(): Int

Deprecated: This method is now obsolete.

This method exists for compatibility and has no effect.

getGlobalFreedCount

Added in API level 1
Deprecated in API level 23
static fun getGlobalFreedCount(): Int

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Returns the global count of objects freed by the runtime between a start and stop.

getGlobalFreedSize

Added in API level 1
Deprecated in API level 23
static fun getGlobalFreedSize(): Int

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Returns the global size, in bytes, of objects freed by the runtime between a start and stop.

getGlobalGcInvocationCount

Added in API level 1
Deprecated in API level 23
static fun getGlobalGcInvocationCount(): Int

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Returns the number of non-concurrent GC invocations between a start and stop.

getLoadedClassCount

Added in API level 1
static fun getLoadedClassCount(): Int

Get the number of loaded classes.

Return
Int the number of loaded classes.

getMemoryInfo

Added in API level 1
static fun getMemoryInfo(memoryInfo: Debug.MemoryInfo!): Unit

Retrieves information about this processes memory usages. This information is broken down by how much is in use by dalvik, the native heap, and everything else.

Note: this method directly retrieves memory information for the given process from low-level data available to it. It may not be able to retrieve information about some protected allocations, such as graphics. If you want to be sure you can see all information about allocations by the process, use android.app.ActivityManager#getProcessMemoryInfo(int[]) instead.

getNativeHeapAllocatedSize

Added in API level 1
static fun getNativeHeapAllocatedSize(): Long

Returns the amount of allocated memory in the native heap.

Return
Long The allocated size in bytes.

getNativeHeapFreeSize

Added in API level 1
static fun getNativeHeapFreeSize(): Long

Returns the amount of free memory in the native heap.

Return
Long The freed size in bytes.

getNativeHeapSize

Added in API level 1
static fun getNativeHeapSize(): Long

Returns the size of the native heap.

Return
Long The size of the native heap in bytes.

getPss

Added in API level 14
static fun getPss(): Long

Retrieves the PSS memory used by the process as given by the smaps.

getRss

Added in API level 35
static fun getRss(): Long

Retrieves the RSS memory used by the process as given by the status file.

getRuntimeStat

Added in API level 23
static fun getRuntimeStat(statName: String!): String!

Returns the value of a particular runtime statistic or null if no such runtime statistic exists.

The following table lists the runtime statistics that the runtime supports. All statistics are approximate. Individual allocations may not be immediately reflected in the results. Note runtime statistics may be added or removed in a future API level.

Runtime statistic name Meaning Example Supported (API Levels)
art.gc.gc-count The number of garbage collection runs. 164 23
art.gc.gc-time The total duration of garbage collection runs in ms. 62364 23
art.gc.bytes-allocated The total number of bytes that the application allocated. 1463948408 23
art.gc.bytes-freed The total number of bytes that garbage collection reclaimed. 1313493084 23
art.gc.blocking-gc-count The number of blocking garbage collection runs. 2 23
art.gc.blocking-gc-time The total duration of blocking garbage collection runs in ms. 804 23
art.gc.gc-count-rate-histogram Every 10 seconds, the gc-count-rate is computed as the number of garbage collection runs that have occurred over the last 10 seconds. art.gc.gc-count-rate-histogram is a histogram of the gc-count-rate samples taken since the process began. The histogram can be used to identify instances of high rates of garbage collection runs. For example, a histogram of "0:34503,1:45350,2:11281,3:8088,4:43,5:8" shows that most of the time there are between 0 and 2 garbage collection runs every 10 seconds, but there were 8 distinct 10-second intervals in which 5 garbage collection runs occurred. 0:34503,1:45350,2:11281,3:8088,4:43,5:8 23
art.gc.blocking-gc-count-rate-histogram Every 10 seconds, the blocking-gc-count-rate is computed as the number of blocking garbage collection runs that have occurred over the last 10 seconds. art.gc.blocking-gc-count-rate-histogram is a histogram of the blocking-gc-count-rate samples taken since the process began. The histogram can be used to identify instances of high rates of blocking garbage collection runs. For example, a histogram of "0:99269,1:1,2:1" shows that most of the time there are zero blocking garbage collection runs every 10 seconds, but there was one 10-second interval in which one blocking garbage collection run occurred, and there was one interval in which two blocking garbage collection runs occurred. 0:99269,1:1,2:1 23
Parameters
statName String!: the name of the runtime statistic to look up.
Return
String! the value of the specified runtime statistic or null if the runtime statistic doesn't exist.

getRuntimeStats

Added in API level 23
static fun getRuntimeStats(): MutableMap<String!, String!>!

Returns a map of the names/values of the runtime statistics that getRuntimeStat(java.lang.String) supports.

Return
MutableMap<String!, String!>! a map of the names/values of the supported runtime statistics.

getThreadAllocCount

Added in API level 1
Deprecated in API level 23
static fun getThreadAllocCount(): Int

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Returns the thread-local count of objects allocated by the runtime between a start and stop.

getThreadAllocSize

Added in API level 1
Deprecated in API level 23
static fun getThreadAllocSize(): Int

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Returns the thread-local size of objects allocated by the runtime between a start and stop.

Return
Int The allocated size in bytes.

getThreadExternalAllocCount

Added in API level 1
Deprecated in API level 15
static fun getThreadExternalAllocCount(): Int

Deprecated: This method is now obsolete.

This method exists for compatibility and has no effect.

getThreadExternalAllocSize

Added in API level 1
Deprecated in API level 15
static fun getThreadExternalAllocSize(): Int

Deprecated: This method is now obsolete.

This method exists for compatibility and has no effect.

getThreadGcInvocationCount

Added in API level 1
Deprecated in API level 23
static fun getThreadGcInvocationCount(): Int

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Returns the number of thread-local non-concurrent GC invocations between a start and stop.

isDebuggerConnected

Added in API level 1
static fun isDebuggerConnected(): Boolean

Determine if a debugger is currently attached.

printLoadedClasses

Added in API level 1
static fun printLoadedClasses(flags: Int): Unit

Dump a list of all currently loaded class to the log file.

Parameters
flags Int: See constants above.

resetAllCounts

Added in API level 1
Deprecated in API level 23
static fun resetAllCounts(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Clears all the global and thread-local memory allocation counters.

resetGlobalAllocCount

Added in API level 1
Deprecated in API level 23
static fun resetGlobalAllocCount(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Clears the global count of objects allocated.

resetGlobalAllocSize

Added in API level 1
Deprecated in API level 23
static fun resetGlobalAllocSize(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Clears the global size of objects allocated.

resetGlobalClassInitCount

Added in API level 8
Deprecated in API level 23
static fun resetGlobalClassInitCount(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Clears the count of classes initialized.

resetGlobalClassInitTime

Added in API level 8
Deprecated in API level 23
static fun resetGlobalClassInitTime(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Clears the count of time spent initializing classes.

resetGlobalExternalAllocCount

Added in API level 1
Deprecated in API level 15
static fun resetGlobalExternalAllocCount(): Unit

Deprecated: This method is now obsolete.

This method exists for compatibility and has no effect.

resetGlobalExternalAllocSize

Added in API level 1
Deprecated in API level 15
static fun resetGlobalExternalAllocSize(): Unit

Deprecated: This method is now obsolete.

This method exists for compatibility and has no effect.

resetGlobalExternalFreedCount

Added in API level 1
Deprecated in API level 15
static fun resetGlobalExternalFreedCount(): Unit

Deprecated: This method is now obsolete.

This method exists for compatibility and has no effect.

resetGlobalExternalFreedSize

Added in API level 1
Deprecated in API level 15
static fun resetGlobalExternalFreedSize(): Unit

Deprecated: This method is now obsolete.

This method exists for compatibility and has no effect.

resetGlobalFreedCount

Added in API level 1
Deprecated in API level 23
static fun resetGlobalFreedCount(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Clears the global count of objects freed.

resetGlobalFreedSize

Added in API level 1
Deprecated in API level 23
static fun resetGlobalFreedSize(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Clears the global size of objects freed.

resetGlobalGcInvocationCount

Added in API level 1
Deprecated in API level 23
static fun resetGlobalGcInvocationCount(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Clears the count of non-concurrent GC invocations.

resetThreadAllocCount

Added in API level 1
Deprecated in API level 23
static fun resetThreadAllocCount(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Clears the thread-local count of objects allocated.

resetThreadAllocSize

Added in API level 1
Deprecated in API level 23
static fun resetThreadAllocSize(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Clears the thread-local count of objects allocated.

resetThreadExternalAllocCount

Added in API level 1
Deprecated in API level 15
static fun resetThreadExternalAllocCount(): Unit

Deprecated: This method is now obsolete.

This method exists for compatibility and has no effect.

resetThreadExternalAllocSize

Added in API level 1
Deprecated in API level 15
static fun resetThreadExternalAllocSize(): Unit

Deprecated: This method is now obsolete.

This method exists for compatibility and has no effect.

resetThreadGcInvocationCount

Added in API level 1
Deprecated in API level 23
static fun resetThreadGcInvocationCount(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Clears the thread-local count of non-concurrent GC invocations.

setAllocationLimit

Added in API level 1
Deprecated in API level 15
static fun setAllocationLimit(limit: Int): Int

Deprecated: This method is now obsolete.

Establish an object allocation limit in the current thread. This feature was never enabled in release builds. The allocation limits feature was removed in Honeycomb. This method exists for compatibility and always returns -1 and has no effect.

setGlobalAllocationLimit

Added in API level 1
Deprecated in API level 15
static fun setGlobalAllocationLimit(limit: Int): Int

Deprecated: This method is now obsolete.

Establish a global object allocation limit. This feature was never enabled in release builds. The allocation limits feature was removed in Honeycomb. This method exists for compatibility and always returns -1 and has no effect.

startAllocCounting

Added in API level 1
Deprecated in API level 18
static fun startAllocCounting(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Start counting the number and aggregate size of memory allocations.

The start method resets the counts and enables counting. The stop method disables the counting so that the analysis code doesn't cause additional allocations. The various get methods return the specified value. And the various reset methods reset the specified count.

Counts are kept for the system as a whole (global) and for each thread. The per-thread counts for threads other than the current thread are not cleared by the "reset" or "start" calls.

startMethodTracing

Added in API level 1
static fun startMethodTracing(): Unit

Start method tracing with default log name and buffer size.

By default, the trace file is called "dmtrace.trace" and it's placed under your package-specific directory on primary shared/external storage, as returned by Context#getExternalFilesDir(String).

See Inspect Trace Logs with Traceview for information about reading trace files.

When method tracing is enabled, the VM will run more slowly than usual, so the timings from the trace files should only be considered in relative terms (e.g. was run #1 faster than run #2). The times for native methods will not change, so don't try to use this to compare the performance of interpreted and native implementations of the same method. As an alternative, consider using sampling-based method tracing via startMethodTracingSampling(java.lang.String,int,int) or "native" tracing in the emulator via startNativeTracing().

startMethodTracing

Added in API level 1
static fun startMethodTracing(tracePath: String!): Unit

Start method tracing, specifying the trace log file path.

When a relative file path is given, the trace file will be placed under your package-specific directory on primary shared/external storage, as returned by Context#getExternalFilesDir(String).

See Inspect Trace Logs with Traceview for information about reading trace files.

When method tracing is enabled, the VM will run more slowly than usual, so the timings from the trace files should only be considered in relative terms (e.g. was run #1 faster than run #2). The times for native methods will not change, so don't try to use this to compare the performance of interpreted and native implementations of the same method. As an alternative, consider using sampling-based method tracing via startMethodTracingSampling(java.lang.String,int,int) or "native" tracing in the emulator via startNativeTracing().

Parameters
tracePath String!: Path to the trace log file to create. If null, this will default to "dmtrace.trace". If the file already exists, it will be truncated. If the path given does not end in ".trace", it will be appended for you.

startMethodTracing

Added in API level 1
static fun startMethodTracing(
    tracePath: String!,
    bufferSize: Int
): Unit

Start method tracing, specifying the trace log file name and the buffer size.

When a relative file path is given, the trace file will be placed under your package-specific directory on primary shared/external storage, as returned by Context#getExternalFilesDir(String).

See Inspect Trace Logs with Traceview for information about reading trace files.

When method tracing is enabled, the VM will run more slowly than usual, so the timings from the trace files should only be considered in relative terms (e.g. was run #1 faster than run #2). The times for native methods will not change, so don't try to use this to compare the performance of interpreted and native implementations of the same method. As an alternative, consider using sampling-based method tracing via startMethodTracingSampling(java.lang.String,int,int) or "native" tracing in the emulator via startNativeTracing().

Parameters
tracePath String!: Path to the trace log file to create. If null, this will default to "dmtrace.trace". If the file already exists, it will be truncated. If the path given does not end in ".trace", it will be appended for you.
bufferSize Int: The maximum amount of trace data we gather. If not given, it defaults to 8MB.

startMethodTracing

Added in API level 1
static fun startMethodTracing(
    tracePath: String!,
    bufferSize: Int,
    flags: Int
): Unit

Start method tracing, specifying the trace log file name, the buffer size, and flags.

When a relative file path is given, the trace file will be placed under your package-specific directory on primary shared/external storage, as returned by Context#getExternalFilesDir(String).

See Inspect Trace Logs with Traceview for information about reading trace files.

When method tracing is enabled, the VM will run more slowly than usual, so the timings from the trace files should only be considered in relative terms (e.g. was run #1 faster than run #2). The times for native methods will not change, so don't try to use this to compare the performance of interpreted and native implementations of the same method. As an alternative, consider using sampling-based method tracing via startMethodTracingSampling(java.lang.String,int,int) or "native" tracing in the emulator via startNativeTracing().

Parameters
tracePath String!: Path to the trace log file to create. If null, this will default to "dmtrace.trace". If the file already exists, it will be truncated. If the path given does not end in ".trace", it will be appended for you.
bufferSize Int: The maximum amount of trace data we gather. If not given, it defaults to 8MB.
flags Int: Flags to control method tracing. The only one that is currently defined is TRACE_COUNT_ALLOCS.

startMethodTracingSampling

Added in API level 21
static fun startMethodTracingSampling(
    tracePath: String!,
    bufferSize: Int,
    intervalUs: Int
): Unit

Start sampling-based method tracing, specifying the trace log file name, the buffer size, and the sampling interval.

When a relative file path is given, the trace file will be placed under your package-specific directory on primary shared/external storage, as returned by Context#getExternalFilesDir(String).

See Inspect Trace Logs with Traceview for information about reading trace files.

Parameters
tracePath String!: Path to the trace log file to create. If null, this will default to "dmtrace.trace". If the file already exists, it will be truncated. If the path given does not end in ".trace", it will be appended for you.
bufferSize Int: The maximum amount of trace data we gather. If not given, it defaults to 8MB.
intervalUs Int: The amount of time between each sample in microseconds.

startNativeTracing

Added in API level 1
static fun startNativeTracing(): Unit

Enable qemu tracing. For this to work requires running everything inside the qemu emulator; otherwise, this method will have no effect. The trace file is specified on the command line when the emulator is started. For example, the following command line
emulator -trace foo
will start running the emulator and create a trace file named "foo". This method simply enables writing the trace records to the trace file.

The main differences between this and startMethodTracing() are that tracing in the qemu emulator traces every cpu instruction of every process, including kernel code, so we have more complete information, including all context switches. We can also get more detailed information such as cache misses. The sequence of calls is determined by post-processing the instruction trace. The qemu tracing is also done without modifying the application or perturbing the timing of calls because no instrumentation is added to the application being traced.

One limitation of using this method compared to using startMethodTracing() on the real device is that the emulator does not model all of the real hardware effects such as memory and bus contention. The emulator also has a simple cache model and cannot capture all the complexities of a real cache.

stopAllocCounting

Added in API level 1
Deprecated in API level 18
static fun stopAllocCounting(): Unit

Deprecated: Accurate counting is a burden on the runtime and may be removed.

Stop counting the number and aggregate size of memory allocations.

stopMethodTracing

Added in API level 1
static fun stopMethodTracing(): Unit

Stop method tracing.

stopNativeTracing

Added in API level 1
static fun stopNativeTracing(): Unit

Stop qemu tracing. See startNativeTracing() to start tracing.

Tracing can be started and stopped as many times as desired. When the qemu emulator itself is stopped then the buffered trace records are flushed and written to the trace file. In fact, it is not necessary to call this method at all; simply killing qemu is sufficient. But starting and stopping a trace is useful for examining a specific region of code.

threadCpuTimeNanos

Added in API level 1
static fun threadCpuTimeNanos(): Long

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. On system which don't support this operation, the call returns -1.

waitForDebugger

Added in API level 1
static fun waitForDebugger(): Unit

Wait until a debugger attaches. As soon as the debugger attaches, this returns, so you will need to place a breakpoint after the waitForDebugger() call if you want to start tracing immediately.

waitingForDebugger

Added in API level 1
static fun waitingForDebugger(): Boolean

Returns "true" if one or more threads is waiting for a debugger to attach.