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