linux oprofile 手册,Oprofile/operf使用小结

[root@server16 ~]# cat operf.man

OPERF(1) General Commands Manual OPERF(1)

NAME

operf - Performance profiler tool for Linux

SYNOPSIS

operf [ options ] [ --system-wide | --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 /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 /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 /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 com‐

mand , --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 profil‐

ing (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 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 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= 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 (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 sam‐

ples 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 /samples/current to /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 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