android.os
public
final
class
android.os.Debug
Provides various debugging functions 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 Running the Traceview Debugging Program for
information about reading trace files. To start logging trace files, call one
of the startMethodTracing() methods. To stop tracing, call
stopMethodTracing().
Nested Classes
Summary
Constants
Public Methods
clone,
equals,
finalize,
getClass,
hashCode,
notify,
notifyAll,
toString,
wait,
wait,
wait
Details
Constants
public
static
final
int
SHOW_CLASSLOADER
Constant Value:
2
(0x00000002)
public
static
final
int
SHOW_FULL_DETAIL
Flags for printLoadedClasses(). Default behavior is to only show
the class name.
Constant Value:
1
(0x00000001)
public
static
final
int
SHOW_INITIALIZED
Constant Value:
4
(0x00000004)
public
static
final
int
TRACE_COUNT_ALLOCS
Flags for startMethodTracing(). These can be ORed together.
TRACE_COUNT_ALLOCS adds the results from startAllocCounting to the
trace key file.
Constant Value:
1
(0x00000001)
Public Methods
public
static
void
changeDebugPort(int port)
Change the JDWP port -- this is a temporary measure.
If a debugger is currently attached the change may not happen
until after the debugger disconnects.
public
static
void
enableEmulatorTraceOutput()
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().
public
static
final
int
getBinderDeathObjectCount()
Returns the number of death notification links to Binder objects that
exist in the current process.
public
static
final
int
getBinderLocalObjectCount()
Returns the number of active local Binder objects that exist in the
current process.
public
static
final
int
getBinderProxyObjectCount()
Returns the number of references to remote proxy Binder objects that
exist in the current process.
public
static
int
getBinderReceivedTransactions()
Returns the number of received transactions from the binder driver.
Returns
- The number of received transactions or -1 if it could not read the stats.
public
static
int
getBinderSentTransactions()
Returns the number of sent transactions from this process.
Returns
- The number of sent transactions or -1 if it could not read t.
public
static
int
getGlobalAllocCount()
public
static
int
getGlobalAllocSize()
public
static
int
getGlobalExternalAllocCount()
public
static
int
getGlobalExternalAllocSize()
public
static
int
getGlobalExternalFreedCount()
public
static
int
getGlobalExternalFreedSize()
public
static
int
getGlobalFreedCount()
public
static
int
getGlobalFreedSize()
public
static
int
getGlobalGcInvocationCount()
public
static
int
getLoadedClassCount()
Get the number of loaded classes.
Returns
- the number of loaded classes.
public
static
void
getMemoryInfo(Debug.MemoryInfo memoryInfo)
Retrieves information about this processes memory usages. This information is broken down by
how much is in use by dalivk, the native heap, and everything else.
public
static
long
getNativeHeapAllocatedSize()
Returns the amount of allocated memory in the native heap.
Returns
- The allocated size in bytes.
public
static
long
getNativeHeapFreeSize()
Returns the amount of free memory in the native heap.
public
static
long
getNativeHeapSize()
Returns the size of the native heap.
Returns
- The size of the native heap in bytes.
public
static
int
getThreadAllocCount()
public
static
int
getThreadAllocSize()
public
static
int
getThreadExternalAllocCount()
public
static
int
getThreadExternalAllocSize()
public
static
int
getThreadGcInvocationCount()
public
static
boolean
isDebuggerConnected()
Determine if a debugger is currently attached.
public
static
void
printLoadedClasses(int flags)
Dump a list of all currently loaded class to the log file.
Parameters
flags
| See constants above.
|
public
static
void
resetAllCounts()
public
static
void
resetGlobalAllocCount()
public
static
void
resetGlobalAllocSize()
public
static
void
resetGlobalExternalAllocCount()
public
static
void
resetGlobalExternalAllocSize()
public
static
void
resetGlobalExternalFreedCount()
public
static
void
resetGlobalExternalFreedSize()
public
static
void
resetGlobalFreedCount()
public
static
void
resetGlobalFreedSize()
public
static
void
resetGlobalGcInvocationCount()
public
static
void
resetThreadAllocCount()
public
static
void
resetThreadAllocSize()
public
static
void
resetThreadExternalAllocCount()
public
static
void
resetThreadExternalAllocSize()
public
static
void
resetThreadGcInvocationCount()
public
static
int
setAllocationLimit(int limit)
Establish an object allocation limit in the current thread. Useful
for catching regressions in code that is expected to operate
without causing any allocations.
Pass in the maximum number of allowed allocations. Use -1 to disable
the limit. Returns the previous limit.
The preferred way to use this is:
int prevLimit = -1;
try {
prevLimit = Debug.setAllocationLimit(0);
... do stuff that's not expected to allocate memory ...
} finally {
Debug.setAllocationLimit(prevLimit);
}
This allows limits to be nested. The try/finally ensures that the
limit is reset if something fails.
Exceeding the limit causes a dalvik.system.AllocationLimitError to
be thrown from a memory allocation call. The limit is reset to -1
when this happens.
The feature may be disabled in the VM configuration. If so, this
call has no effect, and always returns -1.
public
static
int
setGlobalAllocationLimit(int limit)
Establish a global object allocation limit. This is similar to
setAllocationLimit(int) but applies to all threads in
the VM. It will coexist peacefully with per-thread limits.
[ The value of "limit" is currently restricted to 0 (no allocations
allowed) or -1 (no global limit). This may be changed in a future
release. ]
public
static
void
startAllocCounting()
Count the number and aggregate size of memory allocations between
two points.
The "start" function resets the counts and enables counting. The
"stop" function disables the counting so that the analysis code
doesn't cause additional allocations. The "get" function returns
the specified value.
Counts are kept for the system as a whole and for each thread.
The per-thread counts for threads other than the current thread
are not cleared by the "reset" or "start" calls.
public
static
void
startMethodTracing(String traceName)
Start method tracing, specifying the trace log file name. The trace
file will be put under "/sdcard" unless an absolute path is given.
See
Running the Traceview Debugging Program for
information about reading trace files.
Parameters
traceName
| Name for the trace log file to create.
If no name argument is given, this value defaults to "/sdcard/dmtrace.trace".
If the files already exist, they will be truncated.
If the trace file given does not end in ".trace", it will be appended for you.
|
public
static
void
startMethodTracing(String traceName, int bufferSize)
Start method tracing, specifying the trace log file name and the
buffer size. The trace files will be put under "/sdcard" unless an
absolute path is given. See
Running the Traceview Debugging Program for
information about reading trace files.
Parameters
traceName
| Name for the trace log file to create.
If no name argument is given, this value defaults to "/sdcard/dmtrace.trace".
If the files already exist, they will be truncated.
If the trace file given does not end in ".trace", it will be appended for you. |
bufferSize
| The maximum amount of trace data we gather. If not given, it defaults to 8MB.
|
public
static
void
startMethodTracing(String traceName, int bufferSize, int flags)
Start method tracing, specifying the trace log file name and the
buffer size. The trace files will be put under "/sdcard" unless an
absolute path is given. See
Running the Traceview Debugging Program 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 Java and native implementations of the
same method. As an alternative, consider using "native" tracing
in the emulator via startNativeTracing().
Parameters
traceName
| Name for the trace log file to create.
If no name argument is given, this value defaults to "/sdcard/dmtrace.trace".
If the files already exist, they will be truncated.
If the trace file given does not end in ".trace", it will be appended for you. |
bufferSize
| The maximum amount of trace data we gather. If not given, it defaults to 8MB.
|
public
static
void
startMethodTracing()
public
static
void
startNativeTracing()
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.
public
static
void
stopAllocCounting()
public
static
void
stopMethodTracing()
Stop method tracing.
public
static
void
stopNativeTracing()
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.
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.
On system which don't support this operation, the call returns -1.
public
static
void
waitForDebugger()
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.
public
static
boolean
waitingForDebugger()
Returns "true" if one or more threads is waiting for a debugger
to attach.