DTRACE(1) General Commands Manual DTRACE(1)

dtracedynamic tracing compiler and tracing utility

dtrace [-aACeFhHlqSvVwZ] [-b bufsz] [-c cmd] [-D name [=value]] [-I path] [-L path] [-o output] [-s script] [-U name] [-x arg[=value]] [-p pid] [-P provider [[predicate] action]] [-m [provider:] module [[predicate] action]] [-f [[provider:] module:] function [[predicate] action]] [-n [[[provider:] module:] function:] name [[predicate] action]] [-i probe-id [[predicate] action]] [-W pname]

DTrace is a comprehensive dynamic tracing framework ported from Solaris. DTrace provides a powerful infrastructure that permits administrators, developers, and service personnel to concisely answer arbitrary questions about the behavior of the operating system and user programs.

The dtrace command provides a generic interface to the essential services provided by the DTrace facility, including:

You can use dtrace to create D scripts by using it in a shebang declaration to create an interpreter file. You can also use dtrace to attempt to compile D programs and determine their properties without actually enabling traces using the -e option.

The arguments accepted by the -P, -m, -f, -n, and -i options can include an optional D language predicate enclosed in slashes and an optional D language action statement list enclosed in braces. D program code specified on the command line must be appropriately quoted to avoid interpretation of meta-characters by the shell.

The following options are supported:

=value
Set dtrace target data model. See arch(1) for a list of currently supported architectures.
Claim anonymous tracing state and display the traced data. You can combine the -a option with the -e option to force dtrace to exit immediately after consuming the anonymous tracing state rather than continuing to wait for new data.
Generate directives for anonymous (at boot) tracing and store them to NVRAM. This option constructs a set of dtrace configuration file directives to enable the specified probes for anonymous tracing and then exits. See also -a
bufsz
Set the principal trace buffer size to bufsz. The trace buffer size can include any of the size suffixes k, m, g, or t. If the buffer space cannot be allocated, dtrace attempts to reduce the buffer size or exit depending on the setting of the bufresize property.
cmd
Run the specified command cmd and exit upon its completion. If more than one -c option is present on the command line, dtrace exits when all commands have exited, reporting the exit status for each child process as it terminates. The process ID of the first command is made available to any D programs specified on the command line or using the -s option through the $target macro variable.
Run the C preprocessor in clang(1) over D programs before compiling them. You can pass options to the C preprocessor using the -D, -U, -I, and -H options.
name [=value]
Define name when invoking clang(1) (enabled using the -C option). If you specify an additional value, the name is assigned the corresponding value. This option passes the -D option to each clang(1) invocation.
Exit after compiling any requests and consuming anonymous tracing state (-a option) but prior to enabling any probes. You can combine this option with the -a option to print anonymous tracing data and exit. You can also combine this option with D compiler options. This combination verifies that the programs compile without actually executing them and enabling the corresponding instrumentation.
[[provider:] module:] function [[predicate] action]
Specify function name to trace or list (-l option). The corresponding argument can include any of the probe description forms provider:module:function, module:function, or function. Unspecified probe description fields are left blank and match any probes regardless of the values in those fields. If no qualifiers other than function are specified in the description, all probes with the corresponding function are matched. The -f argument can be suffixed with an optional D probe clause. You can specify more than one -f option on the command line at a time.
Coalesce trace output by identifying function entry and return. Function entry probe reports are indented and their output is prefixed with ‘->’. Function return probe reports are unindented and their output is prefixed with ‘<-’. System call entry probe reports are indented and their output is prefixed with ‘=>’. System call return probe reports are unindented and their output is prefixed with ‘<=’.
Generate a header file containing macros that correspond to probes in the specified provider definitions. If the -o option is present, the header file is saved using the pathname specified as the argument for that option. If the -o option is not present and the DTrace program is contained within a file whose name is filename.d, then the header file is saved using the name filename.h.
Print the pathnames of included files when invoking clang(1) (enabled using the -C option). This option passes the -H option to each clang(1) invocation, causing it to display the list of pathnames, one for each line, to standard error.
probe-id [[predicate] action]
Specify probe identifier (probe-id) to trace or list (l option). You can specify probe IDs using decimal integers as shown by `dtrace -l`. The -i argument can be suffixed with an optional D probe clause. You can specify more than one -i option at a time.
path
Add the specified directory path to the search path for #include files when invoking clang(1) (enabled using the -C option). This option passes the -I option to each clang(1) invocation. The specified path is inserted into the search path ahead of the default directory list.
List probes instead of enabling them. If the -l option is specified, dtrace produces a report of the probes matching the descriptions given using the -P, -m, -f, -n, -i, and -s options. If none of these options are specified, this option lists all probes.
path
Add the specified directory path to the search path for DTrace libraries. DTrace libraries are used to contain common definitions that can be used when writing D programs. The specified path is added after the default library search path.
[provider:] module [[predicate] action]
Specify module name to trace or list (-l option). The corresponding argument can include any of the probe description forms provider:module or module. Unspecified probe description fields are left blank and match any probes regardless of the values in those fields. If no qualifiers other than module are specified in the description, all probes with a corresponding module are matched. The -m argument can be suffixed with an optional D probe clause. More than one -m option can be specified on the command line at a time.
[[[provider:] module:] function:] name [[predicate] action]
Specify probe name to trace or list (-l option). The corresponding argument can include any of the probe description forms provider:module:function:name, module:function:name, function:name, or name. Unspecified probe description fields are left blank and match any probes regardless of the values in those fields. If no qualifiers other than name are specified in the description, all probes with a corresponding name are matched. The -n argument can be suffixed with an optional D probe clause. More than one -n option can be specified on the command line at a time.
output
Specify the output file for the -l options, or for the traced data itself. The default output file is d.out.
pid
Grab the specified process-ID pid, cache its symbol tables, and exit upon its completion. If more than one -p option is present on the command line, dtrace exits when all commands have exited, reporting the exit status for each process as it terminates. The first process-ID is made available to any D programs specified on the command line or using the -s option through the $target macro variable.
provider [[predicate] action]
Specify provider name to trace or list (-l option). The remaining probe description fields module, function, and name are left blank and match any probes regardless of the values in those fields. The -P argument can be suffixed with an optional D probe clause. You can specify more than one -P option on the command line at a time.
Set quiet mode. dtrace suppresses messages such as the number of probes matched by the specified options and D programs and does not print column headers, the CPU ID, the probe ID, or insert newlines into the output. Only data traced and formatted by D program statements such as ‘dtrace()’ and ‘printf()’ is displayed to standard output.
script
Compile the specified D program source file. If the -e option is present, the program is compiled but instrumentation is not enabled. If the -l option is present, the program is compiled and the set of probes matched by it is listed, but instrumentation is not enabled.

If none of -e, -l or -A are present, the instrumentation specified by the D program is enabled and tracing begins.

Show D compiler intermediate code. The D compiler produces a report of the intermediate code generated for each D program to standard error.
name
Undefine the specified name when invoking clang(1) (enabled using the -C option). This option passes the -U option to each clang(1) invocation.
Print an interface stability report for a specified D program or listed probes. If probes are being listed with -l, report on each probe's description, arguments, and argument types (if available).
Report the highest D programming interface version supported by dtrace. The version information is printed to standard output and the dtrace command exits.
Permit destructive actions in D programs. Without -w, dtrace will not permit the compilation or enabling of a D program that contains destructive actions. Even with -w, destructive actions are not allowed if System Integrity Protection is enabled. See csrutil(8).
pname
Wait for the process named pname to launch. Once it has launched, compile and enable the provided D script. Upon exit of the process, dtrace exits. If more than one -W option is present on the command line, dtrace will stop each process immediately after it launches, start tracing when all processes have launched, and exit after all processes have exited. Only the first-specified process's PID will be available to D programs through the $target macro variable. Using this option automatically activates the -Z option.
arg[=value]
Enable or modify a DTrace runtime option or D compiler option. Boolean options are enabled by specifying their name. Options with values are set by separating the option name and value with an equals sign (=). See EXTRA OPTIONS for the exhaustive list of options.
Permit probe descriptions that match zero probes. If the -Z option is not specified, dtrace reports an error and exits if any probe descriptions specified in D program files (-s option) or on the command line (-P, -m, -f, -n, or -i options) contain descriptions that do not match any known probes.

Zero or more additional arguments may be specified on the dtrace command line to define a set of macro variables ($1, $2, and so on) to be used in any D programs specified using the -s option or on the command-line.

By default, dtrace uses the demangled names of C++ symbols. You can tell dtrace to use the mangled symbol names by passing -xmangled to the command.

The Objective-C provider is similar to the pid provider, and allows instrumentation of Objective-C classes and methods. Objective-C probe specifiers use the following format:

objcpid:[class-name[(category-name)]]:[[+|-]method-name]:[name]

pid
The id number of the process.
class-name
The name of the Objective-C class.
category-name
The name of the category within the Objective-C class.
method-name
The name of the Objective-C method.
name
The name of the probe, ‘entry’, ‘return’, or an integer instruction offset within the method.

objc123:NSString:-*:entry
Every instance method of class NSString in process 123.
objc123:NSString(*)::entry
Every method on every category of class NSString in process 123.
objc123:NSString(foo):+*:entry
Every class method in NSString's foo category in process 123.
objc123::-*:entry
Every instance method in every class and category in process 123.
objc123:NSString(foo):-dealloc:entry
The dealloc method in the foo category of class NSString in process 123.
objc123::method?with?many?colons?:entry
The method method:with:many:colons: in every class in process 123. (A ? wildcard must be used to match colon characters inside of Objective-C method names, as they would otherwise be parsed as the provider field separators.)

The process of adding USDT probes to code is slightly different than documented in the Solaris Dynamic Tracing Guide. The steps for adding probes are as follows:

  1. Name the provider and specify its probes, using the following form:
    provider Example {
    	probe increment(int);
    };

    This defines the Example provider with one probe, increment, that takes a single int argument. Providers can define multiple probes and probes can take multiple arguments.

  2. Process the provider description into a header file.

    The provider description must be converted into a form usable by ObjC/C/C++ code. The dtrace command should be invoked with the -h option to do this.

    dtrace -h -s exampleProvider.d

    This will generate a header file named exampleProvider.h

  3. Add probe invocations to the application.

    For each probe defined in the provider, the provider.h file will contain two macros. The naming is as follows:

    PROVIDER_PROBENAME()
    PROVIDER_PROBENAME_ENABLED()

    In the Example provider, the increment probe becomes:

    EXAMPLE_INCREMENT()
    EXAMPLE_INCREMENT_ENABLED()

    Place a macro invocation in the code at each site to be traced. If the arguments passed to a probe are expensive to calculate, you may guard the probe placement like this:

    if (EXAMPLE_INCREMENT_ENABLED()) {
    	argument = /* Expensive argument calculation code here */;
    	EXAMPLE_INCREMENT(argument);
    };

    The if test will only succeed when the increment probe is active.

  4. Compile and link your program normally. No additional compiler or linker flags are required.

These options can be set by either passing them to -x or be set in dtrace scripts using option=value.

amin=attributes
Set the values for the minimum stability attributes for D program execution. attributes is a tuple of the form name-stability/data-stability/dependency-class. Valid interface and data stability attribute values are:
  • Internal: interfaces to dtrace implementation details. These interfaces might change between minor releases.
  • Private: interfaces to undocumented operating system implementation details. Might change between minor releases.
  • Obsolete: interfaces to currently-supported features which are scheduled to be removed in a future release.
  • External: interfaces to features not controlled by the operating system vendor.
  • Unstable: interfaces which may change without warning.
  • Evolving: may become Standard or Stable but may still change in a future major release.
  • Stable: Mature interface which should not change.
  • Standard: Complies with an industry standard and will not change.
arch=value
Set the target data model. See arch(1) for a list of currently supported architectures. Has the same effect as the -arch option.
argref
Ignore additional positional command-line arguments instead of reporting an error.
core
After execution is complete, cause dtrace to call abort(3) instead of exit(3). On some systems, this will create a core dump.
cpp
Run the C preprocessor in clang(1) over D programs before compiling them. Has the same effect as the -C option.
cpphdrs
Specify the -H option to clang(1) to print the name of each header file used.
cpppath=path
Sets the path of the clang(1) preprocessor
ctypes=path
Write out CTF definitions of all C types used in all programs at the end of a D compilation run in path.
debug
Enable DTrace debug messages.
defaultargs
Allow references to unspecified macro arguments. Use 0 as the value for an unspecified argument.
define
Adds an implicit #define into the predefines buffer of the preprocessor. Has the same effect as the -D option.
disallow_dsym
Do not use dSYM files for userspace symbolication.
droptags
Prints drop tags, [DTRACE_DROP_$TYPE] values describing drop types, to the drop tags handler (by default, to stderr).
empty
Allow compilation of empty D files.
encoding=[ascii|utf8]
Sets the encoding used for output. utf8 will show Unicode block elements for histograms.
errtags
Prefix default error message with error tags.
evaltime=[preinit|postinit]
Control when DTrace starts instrumenting a new process, before or after library initializers have run.
incdir=value
Add the specified directory to the search path for includes files in the preprocessor.
iregs=value
Size of the DIF (DTrace Intermediate Format) integer register set. The default value is 8.
late=[dynamic|static]
Sets whether references to dynamic translators are allowed.
libdir=path
Add a library directory in the library search path.
mangled
Show mangled symbols for C++/Swift probes instead of demangled symbols.
nolibs
Do not include D system libraries. Prevents access to dtrace system library identifiers but speeds up DTrace launch.
nojtanalysis
Disable jump table analysis. The default behavior of the pid provider is to not provide ‘return’ or offset probes for functions which appear to contain jump tables. "Jump tables are often generated for switch statements." Disabling jump table analysis can lead to inappropriately placed probes, data corruption, or even crashes in the target process.
noerror
Do not show error messages.
pgmax=value
Sets the maximum number of processes DTrace can grab at the same time. Default value is 8.
preallocate=value[k|m]
Preallocate memory in dtrace before running the script.
pspec
Interpret ambiguous specifiers as probe names.
setenv=name=value
Adds the variable name to the environment of launched processes, if name does not already exists. If name does exist in the environment, then its value is set to
strip
Strip non-loadable sections from the D program.
tree=value
Bitmap to show the dtrace compiler parse tree at different stages (1|2|4).
tregs=value
Size of the DIF tuple register set. This controls the number of arguments that can be passed to functions. Default value is 8.
undef=value
Adds an implicit #undef value into the predefines buffer of the preprocessor.
unsetenv=name
Delete the variable name from the environment of launched processes if it exists.
verbose
Show D compiler intermediate code (DIFO). The D compiler will produce a report of the intermediate code generated for each D program to stderr(4) Has the same effect as the -S option.
version
Request a specific version of the DTrace scripting language. This will disable all identifiers / translators / functions that are from a newer version than the specified version.
zdefs
Permit probe descriptions that match zero probes. Has the same effect as the -Z option.

aggsize=value [m|k]
Sets the aggregation buffer size in bytes, kibi or mebibytes.
bufsize=value[m|k]
Sets the principal trace buffer size. Has the same effect as the -b option.
buflimit=1-99
Threshold percentage of buffer size at which early buffer switches will be done. 75% is the default.
bufpolicy=[ring|fill|switch]
Sets the buffer policy. The default buffer policy is switch.
bufresize=[auto|manual]
Sets whether the per-CPU buffer size can be halved when the kernel cannot allocate enough memory. Auto is the default value.
cleanrate=value[ns|us|ms|s|m|h|d|hz]
Cleaning rate for speculative buffers.
cpu=value
CPU on which to enable tracing.
destructive
Allow destructive actions. Has the same effect as the -w option.
dynvarsize=value
Dynamic variable space size.
grabanon
Claim anonymous tracing state and display the trace data. Has the same effect as the -a option.
nspec=value
Number of speculative buffers.
specsize=value[k|m]
Speculation buffer size.
stackframes=value
Number of stack frames shown for kernel backtraces.
statusrate=value[ns|us|ms|s|m|h|d|hz]
Rate at which user space dtrace will poll the kernel for status.
strsize=maxStringSize
Maximum string size.
temporal=[true|false]
Sort events so that output is in time order. Defaults to true.
ustackframes=frameCount
Number of stack frames shown for userspace backtraces.

agghist=file ... [true|false]
Shows a histogram for all aggregations.
aggpack
Pack aggregations together, only showing one line per aggregation.
aggrate=value[us|ms|s|m|h|d|hz]
Sets the aggregation buffer retrieval rate.
aggsortkey
Sort aggregation by key order with ties broken by value.
aggsortkeypos=value
Position of the aggregate key on which the output is sorted.
aggsortpos=value
Position in the argument in the aggregate function on which the output is sorted.
aggsortrev
Sort aggregations in reverse order.
aggzoom
Scales the height of bars in histograms in proportion of the bucket of greatest value instead of the full height of the histogram.
flowindent
Indent function entry/returns with -> / <-. Has the same effect as the -F option.
quiet
Output only explicitly traced data. Has the same effect as the -q option.
rawbytes
Always print tracemem output in hexadecimal.
stackindent
Number of white space characters to use when indenting () or () output.
stacksymbols=frameCount[true|false]
Whether stack symbols are symbolicated or not. Defaults to true.
switchrate=value[ns|us|ms|s|m|h|d|hz]
Rate of principal buffer switching.

dtrace supplies the following built-in, read-only variables.

uint64_t arg0-arg9
Arguments of the current probe invocation represented as unsigned 64-bit integers. In the ‘entry’ probe actions of the syscall, mach_trap, fbt, and pid providers, these variables contain the traced function's arguments. In the ‘return’ probe actions of the fbt and pid providers, arg0 contains the instruction offset (into the function) from which the function returned and arg1 contains the function's return value. In the ‘return’ probe actions of the syscall and mach_trap providers, both arg0 and arg1 are set to the function's return value. The and providers set arg1 to the address of the instruction that was running when the action fired.
args[]
Typed arguments of the current probe, if available. See -v.
uint64_t caller
The kernel address of the instruction that called the current function. As DTrace actions are always called from kernel context, this variable is non-zero even when probes are triggered from user space.
processorid_t cpu
Integer identifier of the logical CPU on which this probe action triggered.
uint64_t cpucycles (Darwin-specific)
Number of CPU cycles elapsed on the current CPU. See also vcycles.
uint64_t cpuinstrs (Darwin-specific)
Number of instructions "retired" by the current logical CPU, if available. This count excludes instructions speculatively issued by the processor which didn't actually need to be executed. See also vinstrs.
thread_t curthread
Address of the OS thread structure corresponding to the thread which triggered the current probe action.
user_addr_t dispatchqaddr (Darwin-specific)
If the probe action was triggered from a user space context which included a dispatch queue, the address of that queue.
uint_t id
The current probe's unique identifier within the currently running OS, as shown with -l.
uint_t epid
A unique identifier representing the current probe action's enablement within the current D program. An action can match multiple probes.
int errno
Error value returned by the last system call performed on the current thread.
string execname
Current process name.
gid_t gid
Primary group ID of the current process.
uint_t ipl
Current interrupt level. On Darwin, either 0 or 1.
uint64_t machtimestamp (Darwin-specific)
Current () timestamp.
uint64_t machctimestamp (Darwin-specific)
Current () timestamp.
pid_t pid
Process ID of the current process.
pid_t ppid
Parent process ID of the current process.
string probeprov, probemod, probefunc, probename
Respectively, the names of the current probe's provider, module, function, and name. See -n.
uint32_t stackdepth
Number of kernel-mode stack frames on the current thread.
id_t tid
Thread ID of the current thread.
uint64_t timestamp
Current value in nanoseconds from some system-wide fixed point in the past.
uid_t uid
User ID of the current process.
uint64_t ucaller
The user space address from which the currently-running function was called, or zero if the function was called from the kernel.
uint32_t ustackdepth
Number of user space stack frames on the current thread.
uint64_t uregs[]
The current thread's register values immediately prior to the last transition from user to kernel execution. /usr/lib/dtrace/regs* provides constants for the indices of each register's value in the array.
uint64_t vmregs[]
The current virtual machine registers if available.
uint64_t vcycles (Darwin-specific)
Number of CPU cycles elapsed while running the current thread. This value includes cycles elapsed while processing interrupts with this thread. See also cpucycles.
uint64_t vinstrs (Darwin-specific)
Number of instructions retired by the current thread, if available. This value includes instructions retired while processing interrupts with this thread. See also cpuinstrs.
uint64_t vtimestamp
Time in nanoseconds that the current thread has spent running on any CPU.
uint64_t walltimestamp
Current number of nanoseconds since the Unix Epoch (00:00 UTC January 1st, 1970).

D subroutines can only effect internal D program state. Many D subroutines have no effects outside the current D program clause.

const char* arguments accept either D string objects or pointers to C strings. C strings are assumed to be terminated with a NUL (0) byte. DTrace pointers refer to kernel virtual address space unless otherwise indicated.

A number of DTrace's subroutines return scratch objects. These scratch objects are only valid for the current invocation of the immediately-enclosing D program clause.

void* (size_t* nbytes)
Create a new nbytes-sized scratch buffer.
string (const char* pathstr)
Copy the last ‘/’-delimited component of pathstr into a new scratch string.
void (void* src, void* scratch, size_t size)
Copy size bytes from address src to the existing scratch buffer scratch.
string (const char* pathstr)
Copy a canonical representation of pathstr into a new scratch string. The resulting string will not contain any unnecessary or redundant ‘./’ or ‘../’ substrings.
void* (user_addr_t src, size_t size)
Copy size bytes from the current user space address src to a new scratch buffer.
string (user_addr_t src, [size_t maxchars])
Copy a NUL-terminated C string from the current user space address src into a new scratch string. If maxchars is specified, it will limit the total number of characters that can be copied. If it is not specified, the run-time option strsize will limit the maximum number of characters copied.
void (user_addr_t src, size_t size, void *scratch)
Copy size bytes from the current user space address src to the existing scratch buffer scratch.
string (const char *pathstr)
Copy all but the last ‘/’-delimited component of pathstr into a new scratch string.
major_t (dev_t dev)
Extract the major device number for dev.
minor_t (dev_t dev)
Extract the minor device number for dev.
uint32_t (uint32_t hostlong)
Convert hostlong from host byte order to network byte order.
uint64_t (uint64_t hostlonglong)
Convert hostlonglong from host byte order to network byte order.
uint16_t (uint16_t hostshort)
Convert hostshort from host byte order to network byte order.
int (const char* str, const char* searchstr, [int start])
Return the character offset of the first occurrence of searchstr within str, optionally starting the search at character offset start.
int (const char* str, const char* searchstr, [int start])
Return the character offset of the last occurrence of the C string searchstr within str, optionally starting the reverse-search at character offset start.
string (uint32_t* addr)
Create a scratch string representing the IPv4 address pointed to by addr in dotted-decimal notation.
string (struct in6_addr* addr)
Create a scratch string representing the IPv6 address pointed to by addr in zero-compressed double-colon hexadecimal notation (specifically RFC 1884 convention 2).
string (int addrfamily, void *addr)
Create a scratch string representing the IP address of type addrfamily pointed to by addr. Valid values for addrfamily are AF_INET and AF_INET6.
string (string payload, string selector)
Extract a single value represented by selector from a JSON object stored in payload. Element selectors support:
  • Simple strings for keys, for example key
  • dot-separated keys for nested objects, for example object.key
  • Array indexing, for example object.key[2].anotherkey
string (int64_t val, [int baseN])
Create a scratch string representing val in base baseN notation.
uint32_t (uint32_t netlong)
Convert netlong from network byte order to host byte order.
uint64_t (uint64_t netlonglong)
Convert netlonglong from network byte order to host byte order.
uint16_t (uint16_t netshort)
Convert netshort from network byte order to host byte order.
int (pid_t pid)
Return non-zero if the calling process has a chain of parent processes leading to pid.
int ()
Return a positive pseudo-random number. It is easy to predict these numbers so they should not be used for cryptographic purposes.
int ()
Create a speculative buffer for use with speculate(), returning the buffer's identifier. See also commit().
string (const char* str, char c)
If str contains c, copy the characters starting at the first occurrence of c and ending at the end of str into a new scratch string. If c is not present, return NULL.
void* (void *ptr, uint8_t key)
On platforms that support encoded pointers, strips the pointer authentication bits from ptr to produce a valid pointer. Valid values for key can be found in ptrauth.h.
string (const char* str, char c)
Like strchr(), but start from the last occurrence of c.
size_t (const char* str)
Calculate the length of str in bytes.
string (const char* str1, const char* str2)
Concatenate str1 and str2 into a new scratch string.
int64_t (const char *str, [int base])
Converts str into a signed integer, interpreted as base base if provided, at base 10 otherwise.
string (const char* str, const char* prefix)
If str contains prefix, copy the characters from prefix to the end of the string into a new scratch string. If prefix is not present, return NULL.
string (const char* str, const char *delimchars)
Like strtok(3), split str into multiple substrings, splitting on any of the characters in delimchars. If the str is non-NULL, return the first token. If str is non-NULL, return the next token from the most recently provided string. delimchars can be changed in subsequent calls. If no characters from delimchars are present whatever portion of str has not yet been tokenized, return NULL.
string (const char* str, int start, [int length])
Copy the characters in str from character offset start through the end of the string into a new scratch string. length can be used to limit the number of characters copied to the new string.
string (const char *str)
Copy str into a new scratch string, replacing all uppercase letters with their lowercase equivalents.
uint64_t (uint64_t time) (Darwin-specific)
Convert time from either machtimestamp or machctimestamp, into nanoseconds.
string (const char* str)
Copy str into a new scratch string, replacing all lowercase letters with their uppercase equivalents.
void* (void* addr) (Darwin-specific)
Calculate the unpermuted (or "unslid") address corresponding to the raw kernel address addr. By default, DTrace uses, traces, and prints raw kernel addresses. Unpermuted addresses will correspond with other user-visible addresses such as those shown in kextstat(8). With default System Integrity Protection settings, D programs are not permitted to access kernel address values or kernel memory contents. csrutil(8) can be used to change the settings.

DTrace actions allow a D program to interact with the running system. The most benign actions record data to a DTrace buffer. Destructive actions have effects on the system and must be enabled with -w.

void* pointers may refer to either D scratch buffers or kernel virtual addresses.

void () (destructive)
Stop the kernel and wait for a debugger.
void (int nsecs) (destructive)
Spin inside DTrace for the specified number of nanoseconds. If this action is asked to spin for more than 500ms out of every second of wall clock time, an error will be reported.
void (@aggr)
Clear all values in @aggr. The keys are retained. See also ().
void (int specid)
Copy the contents of the speculative buffer specid to the main tracing buffer.
void (void *src, user_addr_t *dst, size_t size) (destructive)
Copy size bytes from the buffer src into the current address space address dst.
void (void *src, user_addr_t *dst, size_t maxbytes) (destructive)
Copy a NUL-terminated C string from src to the current user address space address dst, copying no more than maxbytes.
void (int specid)
Discard the speculative buffer specid.
void (int status)
Stop tracing, cause dtrace to print any final results, and exit with status.
void (const char* path) (destructive)
Open path and associate it with dtrace's standard output (closing any previously-associated file).
void ()
Truncate dtrace's stdout.
void (uint32_t debugid, [uint64_t arg1], [uint64_t arg2], [uint64_t arg3], [uint64_t arg4])
(destructive, Darwin-specific)
Emit an event to kdebug trace; arguments are optional and default to zero. debugid is a four-part bit field definied in sys/kdebug.h.
void (uint32_t debugid, uint64_t str_id, const char* str)
(destructive, Darwin-specific)
Emit a string identified with str_id to kdebug trace. debugid is the same as for kdebug_trace().
_symaddr (user_addr_t addr)
Print the symbol name corresponding to the kernel address addr.
_symaddr (user_addr_t addr)
Print the module name corresponding to the kernel address addr.
void (@aggr, int factor)
When @aggr is traced, all of its values will be divided by factor.
void (@aggr)
Remove any normalization factor from @aggr. Tracing this aggregation will return the total counts.
void () (destructive)
Panic the kernel with a generic message.
void (expression)
Pretty-print expression inculding types and internal data structure. A newline will be included.
void ([Ft string format], @aggr)
Pretty-print @aggr. format can refer to the aggregation's keys in order. The aggregation's value can be accessed with the flag ‘@’. For example, to print just aggregations values, one per line
printa("%@u\n", @a);
void (string format, ...)
Print a custom-formatted string like printf(3).
void (int signum) (destructive)
Send signum to the current process.
void (const char* option, [const char* value])
Set a dynamic run-time option. See Dynamic Run-time Options.
void (int specid)
Set the speculative buffer specid as the destination for all further tracing in the current D program clause.
stack stack([int nframes])
Record a kernel stack trace up to nframes deep. If nframes is not specified, record up to stackframes frames. See also Run-time Options.
void () (destructive)
Stop the current user process.
void (pid_t pid) (destructive, Darwin-specific)
Resume the process specified by pid. See also stop() and raise().
_symaddr (user_addr_t addr)
Print the symbol name for the kernel address addr.
void (string program, ...) (destructive)
Spawn program with any provided arguments in the same environment as dtrace.
void (expression)
Print expression. No newline is emitted.
void (addr, size_t nbytes)
Print a hexidecimal representation of nbytes starting at the kernel address addr.
void trunc(@aggr, [topn])
Discard keys and their corresponding values from @aggr, optionally preserving the topn values and their corresponding keys.
_usymaddr (user_addr_t addr)
If available, pretty-print symbol information about the current user space address addr. This information will include applicable module, function, and symbol names, as well as offsets into functions for code. If not available or applicable, just print addr.
_usymaddr (user_addr_t addr)
If available, print the name of the symbol representing addr in the current process's user address space. Otherwise, print addr.
_usymaddr (user_addr_t addr)
If addr is within the boundaries of a known function in the current user space process, print the name of the function. Otherwise, print addr.
_usymaddr (user_addr_t addr)
If addr is within the boundaries of a known module in the current user space process, print the name of the module. Otherwise, print addr.
stack ustack([int nframes])
Record a user stack trace up to nframes deep. If nframes isn't specified, record up to ustackframes frames. See also Run-time Options.

The following exit statuses are returned:

0
Successful completion.

For D program requests, an exit status of 0 indicates that programs were successfully compiled, probes were successfully enabled, or anonymous state was successfully retrieved. dtrace returns 0 even if the specified tracing requests encountered errors or drops.

1
An error occurred.

For D program requests, an exit status of 1 indicates that program compilation failed or that the specified request could not be satisfied.

2
Invalid command line options or arguments were specified.

clang(1), bitesize.d(1m), cpuwalk.d(1m), csrutil(8), diskhits(1m), dtruss(1m), errinfo(1m), execsnoop(1m), iofile.d(1m), iofileb.d(1m), iopattern.d(1m), iopending.d(1m), iosnoop(1m), iotop(1m), kill.d(1m), lastwords(1m), newproc.d(1m), opensnoop(1m)

How to Use Oracle Solaris DTrace from Oracle Solaris and OpenSolaris System, Oracle Corporation, 2010, http://www.oracle.com/technetwork/server-storage/solaris10/solaris-dtrace-wp-167895.pdf.

Solaris Dynamic Tracing Guide, Oracle Corporation, 2010, http://docs.oracle.com/cd/E19253-01/817-6223/.

August 17, 2017 Darwin