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.\" Manpage for operf
.\" Author: Breno Leitao <brenohl@br.ibm.com>
.\" Modifications: Maynard Johnson <maynardj@us.ibm.com>
.TH OPERF 1 "@DATE@" "oprofile @VERSION@"
.SH NAME
operf \- Performance profiler tool for Linux

.SH SYNOPSIS
.B operf
[
.I options
]
[ --system-wide | --pid <pid> | [ command [ args ] ] ]

.SH DESCRIPTION
Operf is an OProfile tool that can be used in place of opcontrol for profiling. Operf
uses the Linux Performance Events Subsystem, and hence, does not require the use of
the opcontrol daemon -- in fact, operf and opcontrol usage are mutually exclusive.
.P
By default, operf uses <current_dir>/oprofile_data as the session-dir and stores profiling data there.
You can change this by way of the
.I --session-dir
option.
.P
The usual post-profiling analysis tools such as
.BI opreport(1)
and
.BI opannotate(1)
can be used to generate profile reports.  The post-processing analysis tools will search for samples in
.I <current_dir>/oprofile_data
first. If that directory does not exist, the post-processing tools use the standard session-dir of /var/lib/oprofile.
.P
Statistics, such as total samples received
and lost samples, are written to the operf.log file that can be found in the
<session_dir>/samples directory.
.br

.SH OPTIONS
.TP
.BI command [args]
The command or application to be profiled.
.I args
are the input arguments that the command or application requires.  One (and only one) of either
.I command
,
.I --pid
or
.I --system-wide
is required.
.br
.TP
.BI "--pid / -p " PID
This option enables operf to profile a running application.
.I PID
should be the process ID of the process you wish to profile.  When
finished profiling (e.g., when the profiled process ends), press
Ctrl-c to stop operf. If you run
.BI operf
.BI --pid
as a background job (i.e., with the &), you
.B must
stop it in a controlled manner in order for it to process the profile
data it has collected.  Use
.BI kill
.BI -SIGINT
.BI <operf-PID>
for this purpose.
.br
.TP
.BI "--system-wide / -s"
This option is for performing a system-wide profile.  You must
have root authority to run operf in this mode.  When finished profiling,
Ctrl-c to stop operf. If you run
.BI operf
.BI --system-wide
as a background job (i.e., with the &), you
.B must
stop it in a controlled manner in order for it to process the profile
data it has collected.  Use
.BI kill
.BI -SIGINT
.BI <operf-PID>
for this purpose.
It is recommended
that when running operf with this option, the user's current working
directory should be /root or a subdirectory of /root to avoid
storing sample data files in locations accessible by regular users.
.br
.TP
.BI "--vmlinux / k " vmlinux_path
A vmlinux file that matches the running kernel that has symbol and/or debuginfo.
Kernel samples will be attributed to this binary, allowing post-processing tools
(like opreport) to attribute samples to the appropriate kernel symbols.
.TP
.BI "--events / -e " event1[,event2[,...]]
This option is for passing a comma-separated list of event specifications
for profiling. Each event spec is of the form:
.br
.I "   name:count[:unitmask[:kernel[:user]]]"
.br
When specifying a unit mask value, it may be either a hexadecimal value (which
.I must
begin with "0x") or a string (i.e, symbolic name) which matches the first word in
the unit mask description. Specifying a symbolic name for the unit mask is valid only
for unit masks having "extra:" parameters, as shown by the output of
.B ophelp.
Unit masks with "extra:" parameters
.I must
be specified using the symbolic name.  If no unit mask is specified, 0x0 will be
used as the default.
.P
.RS
When no event specification is given, the default event for the running
processor type will be used for profiling.
Use
.BI ophelp
to list the available events for your processor type.
.RE
.br
.TP
.BI "--callgraph / -g"
This option enables the callgraph to be saved during profiling. NOTE: The
full callchain is recorded, so there is no depth limit.
.br
.TP
.BI "--separate-thread / -t"
This option categorizes samples by thread group ID (tgid) and thread ID (tid).
The '--separate-thread' option is useful for seeing per-thread samples in
multi-threaded applications.  When used in conjuction with the '--system-wide'
option, the '--separate-thread' option is also useful for seeing per-process
(i.e., per-thread group) samples for the case where multiple processes are
executing the same program during a profiling run.
.br
.TP
.BI "--separate-cpu / -c"
This option categorizes samples by cpu.
.br
.TP
.BI "--session-dir / -d " path
This option specifies the session path to hold the sample data. If not specified,
the data is saved in the
.I oprofile_data
directory on the current path.
.br
.TP
.BI "--lazy-conversion / -l"
Use this option to reduce the overhead of
.BI operf
during profiling. Normally, profile data received from the kernel is converted
to OProfile format during profiling time. This is typically not an issue when
profiling a single application. But when using the
.I --system-wide
option, this on-the-fly conversion process can cause noticeable overhead,
particularly on busy multi-processor systems. The
.I --lazy-conversion
option directs
.BI operf
to wait until profiling is completed to do the conversion of profile data.
.br
.TP
.BI "--append / -a"
By default,
.I operf
moves old profile data from <session_dir>/samples/current to
<session_dir>/samples/previous.  If a 'previous' profile already existed,
it will be replaced.  If the
.I --append
option is passed, old profile data is left in place and new profile data will
be added to it, and the 'previous' profile (if one existed) will remain untouched.
To access the 'previous' profile, simply add a session specification to the normal
invocation of oprofile post-processing tools.  For example:
.br
.BI "   opreport"
.BI session:previous
.br
.TP
.BI "--verbose / -V " level
A comma-separated list of debugging control values, used to increase the verbosity of the output.
Valid values are:  debug, record, convert, misc, sfile, arcs, or the special value, 'all'.
.br
.TP
.BI "--version / -v"
Show operf version.
.br
.TP
.BI "--help / -h"
Show a help message.
.br
.TP
.BI "--usage / -u"
Display brief usage message.
.br

.SH EXAMPLE
$ operf make

.SH VERSION
This man page is current for @PACKAGE@-@VERSION@.

.SH SEE ALSO
opreport(1), opannotate(1).

.SH BUGS
Some parameters are still under development.