illumos: manual page: dtrace.8

DTRACE(8) Maintenance Procedures DTRACE(8)

NAME

dtrace - DTrace dynamic tracing compiler and tracing utility

SYNOPSIS

dtrace [-32 | -64] [-aACeFGHhlqSvVwZ] [-b bufsz] [-c cmd]
[-D name [=value]] [-I path] [-L path] [-o output]
[-s script] [-U name] [-x arg [=val]]
[-X a | c | s | t] [-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]]

DESCRIPTION

DTrace is a comprehensive dynamic tracing framework. 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 Dynamic Tracing Guide describes how to use DTrace to observe, debug,
and tune system behavior. Refer to this book for a detailed description
of DTrace features, including the bundled DTrace observability tools,
instrumentation providers, and the D programming language.

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

o Options that list the set of probes and providers currently
published by DTrace

o Options that enable probes directly using any of the probe
description specifiers (provider, module, function, name)

o Options that run the D compiler and compile one or more D
program files or programs written directly on the command line

o Options that generate anonymous tracing programs

o Options that generate program stability reports

o 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 #! declaration to
create an interpreter file. You can also use dtrace to attempt to compile
D programs and determine their properties without actually enabling
tracing using the -e option. See OPTIONS. See the Dynamic Tracing Guide
for detailed examples of how to use the dtrace utility to perform these
tasks.

OPTIONS

The arguments accepted by the -P, -m, -f, -n, and -i options can include
an optional D language predicate enclosed in slashes // and 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. You can use the isainfo -b command to
determine the current operating system data model. 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 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. See the Dynamic Tracing Guide for
more information about anonymous tracing.

-A

Generate driver.conf(5) directives for anonymous tracing. This option
constructs a set of dtrace(4D) 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
/kernel/drv/dtrace.conf. You can modify this behavior if you use the
-o option to specify an alternate output file.

-b bufsz

Set principal trace buffer size (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. Refer to the
Dynamic Tracing Guide for more information on macro variables.

-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 the equals sign (=) and additional value, the name is
assigned the corresponding value. This option passes the -D option to
each cpp 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]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.

-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

Print the pathnames of included files when invoking cpp(1) (enabled
using the -C option). This option passes the -H option to each cpp
invocation, causing it to display the list of pathnames, one for each
line, to stderr.

-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 with a file whose name is filename.d, then the header file
is saved using the name filename.h.

-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 invocation. The specified path is
inserted into the search path ahead of the default directory list.

-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.

-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.

-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 [[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.

-o output

Specify the output file for the -A, -G, -h, 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 /kernel/drv/dtrace.conf. 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. Refer to
the Dynamic Tracing Guide for more information on macro variables.

-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 trace() and printf() is displayed to stdout.

-s

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 stderr.

-U name

Undefine the specified name when invoking cpp(1) (enabled using the
-C option). This option passes the -U option to each cpp 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. DTrace stability
levels are explained in further detail in the Dynamic Tracing Guide.

-V

Report the highest D programming interface version supported by
dtrace. The version information is printed to stdout and the dtrace
command exits. Refer to the Dynamic Tracing Guide for more
information about DTrace versioning features.

-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 [=val]

Enable or modify a DTrace runtime option or D compiler option. The
list of options is found in the Dynamic Tracing Guide. Boolean
options are enabled by specifying their name. Options with values are
set by separating the option name and value with an equals sign (=).

-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 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 is invoked in conjunction with the -Xc
option.

s
K&R C only. The macro __STDC__ is not defined when cpp 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 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:

o __sun

o __unix

o __SVR4

o __sparc (on SPARC systems only)

o __sparcv9 (on SPARC systems only when 64-bit programs are
compiled)

o __i386 (on x86 systems only when 32-bit programs are
compiled)

o __amd64 (on x86 systems only when 64-bit programs are
compiled)

o __`uname -s`_`uname -r` (for example, __SunOS_5_10)

o __SUNW_D=1

o __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. Refer to the Dynamic
Tracing Guide for more information about DTrace
versioning.

-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.

OPERANDS

You can specify zero or more additional arguments on the dtrace command
line to define a set of macro variables ($1, $2, and so forth). The
additional arguments can be used in D programs specified using the -s
option or on the command line. The use of macro variables is described
further in the Dynamic Tracing Guide.

EXIT STATUS

The following exit values 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.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:

+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | See below. |
+--------------------+-----------------+

The command-line syntax is Committed. The human-readable output is
Uncommitted.

NOTES

When using the -p flag, dtrace stops the target processes while it is
inspecting them and reporting results. A process can do nothing while it
is stopped. This means that, if, for example, the X server is inspected
by dtrace running in a window under the X server's control, the whole
window system can become deadlocked, because the proc tool would be
attempting to display its results to a window that cannot be refreshed.
In such a case, logging in from another system using ssh(1) and killing
the offending proc tool clears the deadlock.

December 10, 2017 DTRACE(8)