OPERF(1)OPERF(1)NAMEoperf - Performance profiler tool for Linux
SYNOPSISoperf [ 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 opanno‐
tate(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 writ‐
ten to the operf.log file that can be found in the <session_dir>/sam‐
ples 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 back‐
ground job (i.e., with the &), you must stop it in a controlled
manner in order for it to process the profile data it has col‐
lected. 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 subdirec‐
tory 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 spec‐
ifications 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 '--sep‐
arate-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 direc‐
tory on the current path.
--lazy-conversion / -l
Use this option to reduce the overhead of operf during profil‐
ing. Normally, profile data received from the kernel is con‐
verted to OProfile format during profiling time. This is typi‐
cally 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>/sam‐
ples/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 pro‐
file 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 invo‐
cation 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
This man page is current for oprofile-0.9.9.
SEE ALSOopreport(1), opannotate(1).
oprofile 0.9.9 Tue 06 August 2013 OPERF(1)
