Ubuntu Manpage: operf - Performance profiler tool for Linux

Provided by: oprofile_0.9.9-0ubuntu8_amd64

NAME

       operf - Performance profiler tool for Linux

SYNOPSIS

       operf [ options ] [ --system-wide | --pid <pid> | [ command [ args ] ] ]

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.

       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 --session-dir option.

       The usual post-profiling analysis tools such as opreport(1) and opannotate(1) can  be  used  to  generate
       profile    reports.     The    post-processing    analysis    tools    will   search   for   samples   in
       <current_dir>/oprofile_data first. If that directory does not exist, the post-processing  tools  use  the
       standard session-dir of /var/lib/oprofile.

       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.

OPTIONS

command[args]
The command or application to be profiled. args are the input arguments that the command or
application requires. One (and only one) of either command , --pid or --system-wide is required.

--pid / -p PID
This option enables operf to profile a running application. 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 operf --pid as a background job (i.e., with the &), you
must stop it in a controlled manner in order for it to process the profile data it has collected.
Use kill -SIGINT <operf-PID> for this purpose.

--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 operf --system-wide as a
background job (i.e., with the &), you must stop it in a controlled manner in order for it to
process the profile data it has collected. Use kill -SIGINT <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.

--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.

--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:
name:count[:unitmask[:kernel[:user]]]
You can specify unit mask values using either a numerical value (hex values must begin with "0x")
or a symbolic name (if the name=<um_name> field is shown in the ophelp output). For some named
unit masks, the hex value is not unique; thus, OProfile tools enforce specifying such unit masks
value by name.

Event names for some IBM PowerPC systems include a _GRP<n> (group number) suffix. You can pass
either the full event name or the base event name (i.e., without the suffix) to operf. If the
base event name is passed, operf will automatically choose an appropriate group number suffix for
the event; thus, OProfile post-processing tools will always show real event names that include the
group number suffix.

When no event specification is given, the default event for the running processor type will be
used for profiling. Use ophelp to list the available events for your processor type.

--callgraph / -g
This option enables the callgraph to be saved during profiling. NOTE: The full callchain is
recorded, so there is no depth limit.

--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 conjunction 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.

--separate-cpu / -c
This option categorizes samples by cpu.

--session-dir / -d path
This option specifies the session path to hold the sample data. If not specified, the data is
saved in the oprofile_data directory on the current path.

--lazy-conversion / -l
Use this option to reduce the overhead of 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 --system-wide option, this on-the-
fly conversion process can cause noticeable overhead, particularly on busy multi-processor
systems. The --lazy-conversion option directs operf to wait until profiling is completed to do the
conversion of profile data.

--append / -a
By default, 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 --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:
opreport session:previous

--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'.

--version / -v
Show operf version.

--help / -h
Display brief usage message.

--usage / -u
Display brief usage message.

EXAMPLE

       $ operf make

VERSION