Manual Pages  — DTRACE

dtrace – dynamic tracing compiler and tracing utility

SYNOPSIS DESCRIPTION OPTIONS OPERANDS FILES EXIT STATUS HISTORY SEE ALSO

dtrace [-32 | -64] [-aACeFGhHlqSvVwZ] [-b bufsz] [-c cmd] [-D name [=value]] [-I path] [-L path] [-o output] [-s script] [-U name] [-x arg [=value]] [-X a | c | s | t] [-p pid] [-P provider [[predicate ]action ]] [-m [provider : ]module [[predicate ]action ]] [-f [[provider : ]module : ]function [[predicate]
Oc Ar action Oc [-n [[[provider : ]module : ]function : ]name]
Oo Oo Ar predicate Oc Ar action Oc [-i probe-id [[predicate ]action ]]

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:

• Options that list the set of probes and providers currently published by DTrace
• Options that enable probes directly using any of the probe description specifiers (provider, module, function, name)
• Options that run the D compiler and compile one or more D program files or programs written directly on the command line
• Options that generate anonymous tracing programs
• Options that generate program stability reports
• Options that modify DTrace tracing and buffering behavior and enable additional D compiler features

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:

-32 | -64
	The D compiler produces programs using the native data model of the operating system kernel. If the -32 option is specified, dtrace forces the D compiler to compile a D program using the 32-bit data model. If the -64 option is specified, dtrace forces the D compiler to compile a D program using the 64-bit data model. These options are typically not required as dtrace selects the native data model as the default. The data model affects the sizes of integer types and other language properties. D programs compiled for either data model can be executed on both 32-bit and 64-bit kernels. The -32 and -64 options also determine the elf(5) file format (ELF32 or ELF64) produced by the -G option.
-a
	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.
-A
	Generate directives for anonymous tracing and write them to /boot/dtrace.dof. This option constructs a set of dtrace configuration file directives to enable the specified probes for anonymous tracing and then exits. By default, dtrace attempts to store the directives to the file /boot/dtrace.dof. This behavior can be modified using the -o option to specify an alternate output file.
-b 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.
-c 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.
-C
	Run the C preprocessor cpp(1) over D programs before compiling them. You can pass options to the C preprocessor using the -D, -U, -I, and -H options. You can select the degree of C standard conformance if you use the -X option. For a description of the set of tokens defined by the D compiler when invoking the C preprocessor, see -X.
-D name [=value]
	Define name when invoking cpp(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 cpp(1) invocation.
-e
	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.
-f [[provider : ]module : ]function [[predicate
	Oc Ar action Oc 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.
-F
	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 ‘<=’.
-G
	Generate an ELF file containing an embedded DTrace program. The DTrace probes specified in the program are saved inside of a relocatable ELF object which can be linked into another program. If the -o option is present, the ELF file is saved using the pathname specified as the argument for this operand. If the -o option is not present and the DTrace program is contained with a file whose name is filename.d, then the ELF file is saved using the name filename.o. Otherwise the ELF file is saved using the name d.out.
-h
	Generate a header file containing macros that correspond to probes in the specified provider definitions. This option should be used to generate a header file that is included by other source files for later use with the -G option. 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.
-H
	Print the pathnames of included files when invoking cpp(1) (enabled using the -C option). This option passes the -H option to each cpp(1) invocation, causing it to display the list of pathnames, one for each line, to standard error.
-i 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.
-I path
	Add the specified directory path to the search path for #include files when invoking cpp(1) (enabled using the -C option). This option passes the -I option to each cpp(1) invocation. The specified path is inserted into the search path ahead of the default directory list.
-l
	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.
-L 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.
-m [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.
-n [[[provider : ]module : ]function : ]name
	Oo Oo Ar predicate Oc Ar action Oc 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.
-o output
	Specify the output file for the -A -, -G, and -l options, or for the traced data itself. If the -A option is present and -o is not present, the default output file is /boot/dtrace.dof. If the -G option is present and the -s option's argument is of the form filename.d and -o is not present, the default output file is filename.o. Otherwise the default output file is d.out.
-p 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.
-P 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.
-q
	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.
-s 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 -, -G, or -A are present, the instrumentation specified by the D program is enabled and tracing begins.
-S
	Show D compiler intermediate code. The D compiler produces a report of the intermediate code generated for each D program to standard error.
-U name
	Undefine the specified name when invoking cpp(1) (enabled using the -C option). This option passes the -U option to each cpp(1) invocation.
-v
	Set verbose mode. If the -v option is specified, dtrace produces a program stability report showing the minimum interface stability and dependency level for the specified D programs.
-V
	Report the highest D programming interface version supported by dtrace. The version information is printed to standard output and the dtrace command exits.
-w
	Permit destructive actions in D programs specified using the -s -, -P -, -m -, -f -, -n, or -i options. If the -w option is not specified, dtrace does not permit the compilation or enabling of a D program that contains destructive actions.
-x 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 (=). A size argument may be suffixed with one of K, M, G or T (either upper or lower case) to indicate a multiple of Kilobytes, Megabytes, Gigabytes or Terabytes respectively. A time argument may be suffixed with one of ns, nsec, us, usec, ms, msec, s, sec, m, min, h, hour, d, day, hz. If no suffix is specified hz will be used as the unit.
aggrate=time
	Rate of aggregation reading.
aggsize=size
	Size of the aggregation buffer.
bufpolicy= fill| switch| ring
	Specifies the buffer policy for the principal buffer.
bufresize= auto| manual
	Buffer resizing policy.
bufsize=size
	Size of the per-CPU principal buffer. Same as the -b flag.
cleanrate=time
	Cleaning rate. Must be specified in number-per-second with the "hz" suffix.
cpu=scalar
	Specifies the CPU on which to enable tracing.
defaultargs
	Allow references to unspecified macro arguments.
destructive
	Allow destructive actions. Same as the -w flag.
dynvarsize=size
	Size of the dynamic variable space.
flowindent
	Turn on flow indentation. Same as the -F flag.
grabanon
	Claim anonymous state. Same as the -a flag.
jstackframes=scalar
	Number of default stack frames for jstack().
jstackstrsize=scalar
	Default string space size for jstack().
nspec=scalar
	Number of speculations.
quiet	Set quiet mode. Same as the -q flag.
specsize=size
	Size of the speculation buffer.
strsize=size
	Maximum size of strings.
stackframes=scalar
	Maximum number of kernelspace stack frames to unwind when executing the stack() action.
stackindent=scalar
	Number of whitespace characters to use when indenting stack() and ustack() output.
statusrate=time
	Rate of status checking.
switchrate=time
	Rate of buffer switching.
ustackframes=scalar
	Maximum number of userspace stack frames to unwind when executing the ustack() action.

-X a | c | s | t
	Specify the degree of conformance to the ISO C standard that should be selected when invoking cpp(1) (enabled using the -C option). The -X option argument affects the value and presence of the __STDC__ macro depending upon the value of the argument letter. The -X option supports the following arguments:
a	Default. ISO C plus K&R compatibility extensions, with semantic changes required by ISO C. This is the default mode if -X is not specified. The predefined macro __STDC__ has a value of 0 when cpp(1) is invoked in conjunction with the -Xa option.
c	Conformance. Strictly conformant ISO C, without K&R C compatibility extensions. The predefined macro __STDC__ has a value of 1 when cpp(1) is invoked in conjunction with the -amp;Xc option.
s	K&R C only. The macro __STDC__ is not defined when cpp(1) is invoked in conjunction with the -Xs option.
t	Transition. ISO C plus K&R C compatibility extensions, without semantic changes required by ISO C. The predefined macro __STDC__ has a value of 0 when cpp(1) is invoked in conjunction with the -Xt option.

As the -X option only affects how the D compiler invokes the C preprocessor, the -Xa and -Xt options are equivalent from the perspective of D and both are provided only to ease re-use of settings from a C build environment.

Regardless of the -X mode, the following additional C preprocessor definitions are always specified and valid in all modes:

• __sun
• __unix
• __SVR4
• __sparc (on SPARC systems only)
• __sparcv9 (on SPARC systems only when 64-bit programs are compiled)
• __i386 (on x86 systems only when 32-bit programs are compiled)
• __amd64 (on x86 systems only when 64-bit programs are compiled)
• __`uname -s`_`uname -r` (for example, ‘FreeBSD_9.2-RELEASE’.
• __SUNW_D=1
• __SUNW_D_VERSION=0xMMmmmuuu

  Where MM is the major release value in hexadecimal, mmm is the minor release value in hexadecimal, and uuu is the micro release value in hexadecimal.

-Z
	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.

You can specify zero or more additional arguments on the dtrace command line to define a set of macro variables and so forth). The additional arguments can be used in D programs specified using the -s option or on the command line.

/boot/dtrace.dof
	File for anonymous tracing directives.

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.

The dtrace utility first appeared in FreeBSD 7.1 .