Tribblix: manual page: dtrace.8

DTRACE(8) Maintenance Commands and 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)