IOCLASSCOUNT(8) 					    BSD System Manager's Manual 					   IOCLASSCOUNT(8)

NAME

     ioclasscount

SYNOPSIS

     ioclasscount [--track] [--leaks] [--maps=PID] [--site=SITE] [--reset] [--start] [--stop] [--exclude] [--size=BYTES] [--capsize=BYTES]
		  [--tag=tag] [--zsize=BYTES] [classname] [...]

DESCRIPTION

     ioclasscount displays the instance counts of OSObject-based C++ classes in the kernel, incremented by the number of direct subclasses that
     have an instance count of at least 1.  For example, if IONetworkController is not directly instantiated, but its direct subclass IOEthernet-
     Controller has any instances, then IONetworkController's instance count will be at least 1; if another direct subclass such as IOFWController
     has any instances, then IONetworkController's instance count will be at least 2; and so on.  (This modification of instance counts prevents
     unloading of kexts defining superclasses that have no instances, but whose subclasses in other kexts have instances.)

     If classes are specified, instance counts are printed as a comma-separated list in the order specified.  If no classes are specified,
     instance counts for all classes are printed, one per line of output and sorted by name.

     This information is useful for tracking leaks.  Instance counts can also found in the root of the IORegistry in the ``IOKitDiagnostics''
     property.

TRACKING

     DEVELOPMENT or DEBUG kernels support collecting backtraces on IOMemoryDescriptor mapping and wiring of memory, and, when running with boot-
     arg io=0x00400000, on object allocation and calls to IOMalloc*.  With boot-arg io=0x02400000, capturing backtraces is enabled at startup.

     The following operands are available:

     --start	  Start capturing allocations.

     --stop	  Stop capturing allocations.

     --reset	  Reset any collected allocations.

     --track	  Display symbolicated allocation backtraces, with bytes allocated and number of calls accumulated per callsite, ordered by size.

     --maps=pid   Display symbolicated backtraces for mappings created in the process with process id pid with bytes mapped and address, ordered
		  by size. If pid is -1 all processes are displayed.

     --site=site  When displaying backtraces, only those containing the string site are included. For example, site could be an address in the
		  backtrace, a symbol name, or a module name.

     --leaks	  Display symbolicated allocation backtraces for potential leaks, with bytes allocated and number of calls accumulated per call-
		  site, ordered by size. Leaks are detected by scanning kernel virtual memory for pointer references to an allocation; allocations
		  with no references found are a potential leak.

     --exclude	  If names are given, apply the command to all tracking categories excluding these names.

     --size=n	  Only report accumulated sizes >= n bytes. The default is 1 byte.

     --capsize=n  Only capture allocations >= n bytes. The default is 1 byte.

     --tag=tag	  Only report allocations with the vm tag tag .

     --zsize=n	  Only report allocations in the kalloc zone of size n bytes.

EXAMPLES

     Display instance counts for IOPCIDevice and AppleTestPCI:

     /usr/sbin/ioclasscount IOPCIDevice AppleTestPCI
	    IOPCIDevice = 2, AppleTestPCI = 1

     Start collecting backtraces for everything:

     /usr/sbin/ioclasscount --start

     Display backtraces and allocation sizes for everything:

     /usr/sbin/ioclasscount --track

     Display all backtraces and allocation sizes collected for OSData & OSSymbol:

     /usr/sbin/ioclasscount --track OSData OSSymbol

     Display all backtraces and allocation sizes collected except for OSSymbol, IOMalloc*, IOMemoryDescriptor mapping and wiring (names from IOK-
     itDebug.h):

     /usr/sbin/ioclasscount --track --exclude OSSymbol IOMalloc IOWire

SEE ALSO

     ioalloccount(8), ioreg(8)

Darwin								 November 06, 2008							    Darwin