table of contents
| PERF-CONFIG(1) | perf Manual | PERF-CONFIG(1) |
NAME¶
perf-config - Get and set variables in a configuration file.
SYNOPSIS¶
perf config [<file-option>] [section.name[=value] ...] or perf config [<file-option>] -l | --list
DESCRIPTION¶
You can manage variables in a configuration file with this command.
OPTIONS¶
-l, --list
Show current config variables, name and value, for all
sections.
--user
For writing and reading options: write to user
$HOME/.perfconfig file or read it.
--system
For writing and reading options: write to system-wide
$(sysconfdir)/perfconfig or read it.
CONFIGURATION FILE¶
The perf configuration file contains many variables to change various aspects of each of its tools, including output, disk usage, etc. The $HOME/.perfconfig file is used to store a per-user configuration. The file $(sysconfdir)/perfconfig can be used to store a system-wide default configuration.
One an disable reading config files by setting the PERF_CONFIG environment variable to /dev/null, or provide an alternate config file by setting that variable.
When reading or writing, the values are read from the system and user configuration files by default, and options --system and --user can be used to tell the command to read from or write to only that location.
Syntax¶
The file consist of sections. A section starts with its name surrounded by square brackets and continues till the next section begins. Each variable must be in a section, and have the form name = value, for example:
[section]
name1 = value1
name2 = value2
Section names are case sensitive and can contain any characters except newline (double quote " and backslash have to be escaped as \" and \\, respectively). Section headers can’t span multiple lines.
Example¶
Given a $HOME/.perfconfig like this:
# # This is the config file, and # a # and ; character indicates a comment #
[colors]
# Color variables
top = red, default
medium = green, default
normal = lightgray, default
selected = white, lightgray
jump_arrows = blue, default
addr = magenta, default
root = white, blue
[tui]
# Defaults if linked with libslang
report = on
annotate = on
top = on
[buildid]
# Default, disable using /dev/null
dir = ~/.debug
[annotate]
# Defaults
hide_src_code = false
use_offset = true
jump_arrows = true
show_nr_jumps = false
[help]
# Format can be man, info, web or html
format = man
autocorrect = 0
[ui]
show-headers = true
[call-graph]
# fp (framepointer), dwarf
record-mode = fp
print-type = graph
order = caller
sort-key = function
[report]
# Defaults
sort_order = comm,dso,symbol
percent-limit = 0
queue-size = 0
children = true
group = true
skip-empty = true
[llvm]
dump-obj = true
clang-opt = -g
You can hide source code of annotate feature setting the config to false with
% perf config annotate.hide_src_code=true
If you want to add or modify several config items, you can do like
% perf config ui.show-headers=false kmem.default=slab
To modify the sort order of report functionality in user config file(i.e. ~/.perfconfig), do
% perf config --user report.sort-order=srcline
To change colors of selected line to other foreground and background colors in system config file (i.e. $(sysconf)/perfconfig), do
% perf config --system colors.selected=yellow,green
To query the record mode of call graph, do
% perf config call-graph.record-mode
If you want to know multiple config key/value pairs, you can do like
% perf config report.queue-size call-graph.order report.children
To query the config value of sort order of call graph in user config file (i.e. ~/.perfconfig), do
% perf config --user call-graph.sort-order
To query the config value of buildid directory in system config file (i.e. $(sysconf)/perfconfig), do
% perf config --system buildid.dir
Variables¶
colors.*
The variables for customizing the colors used in the
output for the report, top and annotate in the TUI. They
should specify the foreground and background colors, separated by a comma, for
example:
medium = green, lightgray
If you want to use the color configured for you terminal, just leave it as 'default', for example:
medium = default, lightgray
Available colors: red, yellow, green, cyan, gray, black, blue, white, default, magenta, lightgray
colors.top
top means a overhead percentage which is more than
5%. And values of this variable specify percentage colors. Basic key values
are foreground-color red and background-color default.
colors.medium
medium means a overhead percentage which has more
than 0.5%. Default values are green and default.
colors.normal
normal means the rest of overhead percentages
except top, medium, selected. Default values are
lightgray and default.
colors.selected
This selects the colors for the current entry in a list
of entries from sub-commands (top, report, annotate). Default values are
black and lightgray.
colors.jump_arrows
Colors for jump arrows on assembly code listings such as
jns, jmp, jane, etc. Default values are blue,
default.
colors.addr
This selects colors for addresses from annotate.
Default values are magenta, default.
colors.root
Colors for headers in the output of a sub-commands (top,
report). Default values are white, blue.
core.*, core.proc-map-timeout
Sets a timeout (in milliseconds) for parsing
/proc/<pid>/maps files. Can be overridden by the --proc-map-timeout
option on supported subcommands. The default timeout is 500ms.
tui., gtk.
Subcommands that can be configured here are top,
report and annotate. These values are booleans, for example:
[tui]
top = true
will make the TUI be the default for the 'top' subcommand. Those will be available if the required libs were detected at tool build time.
buildid.*, buildid.dir
Each executable and shared library in modern
distributions comes with a content based identifier that, if available, will
be inserted in a perf.data file header to, at analysis time find what
is needed to do symbol resolution, code annotation, etc.
The recording tools also stores a hard link or copy in a per-user directory, $HOME/.debug/, of binaries, shared libraries, /proc/kallsyms and /proc/kcore files to be used at analysis time.
The buildid.dir variable can be used to either change this directory cache location, or to disable it altogether. If you want to disable it, set buildid.dir to /dev/null. The default is $HOME/.debug
buildid-cache.*
buildid-cache.debuginfod=URLs Specify debuginfod URLs to
be used when retrieving perf.data binaries, it follows the same syntax as the
DEBUGINFOD_URLS variable, like:
buildid-cache.debuginfod=http://192.168.122.174:8002
annotate.*
These are in control of addresses, jump function, source
code in lines of assembly code from a specific program.
annotate.disassembler_style:
Use this to change the default disassembler style to some other value
supported by binutils, such as "intel", see the '-M' option help in the
'objdump' man page.
annotate.hide_src_code
If a program which is analyzed has source code, this
option lets annotate print a list of assembly code with the source
code. For example, let’s see a part of a program. There’re four
lines. If this option is true, they can be printed without source code
from a program as below.
│ push %rbp │ mov %rsp,%rbp │ sub $0x10,%rsp │ mov (%rdi),%rdx
But if this option is 'false', source code of the part can be also printed as below. Default is 'false'.
│ struct rb_node *rb_next(const struct rb_node *node)
│ {
│ push %rbp
│ mov %rsp,%rbp
│ sub $0x10,%rsp
│ struct rb_node *parent;
│
│ if (RB_EMPTY_NODE(node))
│ mov (%rdi),%rdx
│ return n;
This option works with tui, stdio2 browsers.
annotate.use_offset
Basing on a first address of a loaded function, offset
can be used. Instead of using original addresses of assembly code, addresses
subtracted from a base address can be printed. Let’s illustrate an
example. If a base address is 0XFFFFFFFF81624d50 as below,
ffffffff81624d50 <load0>
an address on assembly code has a specific absolute address as below
ffffffff816250b8:│ mov 0x8(%r14),%rdi
but if use_offset is 'true', an address subtracted from a base address is printed. Default is true. This option is only applied to TUI.
368:│ mov 0x8(%r14),%rdi
This option works with tui, stdio2 browsers.
annotate.jump_arrows
There can be jump instruction among assembly code.
Depending on a boolean value of jump_arrows, arrows can be printed or not
which represent where do the instruction jump into as below.
│ ┌──jmp 1333 │ │ xchg %ax,%ax │1330:│ mov %r15,%r10 │1333:└─→cmp %r15,%r14
If jump_arrow is 'false', the arrows isn't printed as below. Default is 'false'.
│ ↓ jmp 1333 │ xchg %ax,%ax │1330: mov %r15,%r10 │1333: cmp %r15,%r14
This option works with tui browser.
annotate.show_linenr
When showing source code if this option is true,
line numbers are printed as below.
│1628 if (type & PERF_SAMPLE_IDENTIFIER) {
│ ↓ jne 508
│1628 data->id = *array;
│1629 array++;
│1630 }
However if this option is 'false', they aren't printed as below. Default is 'false'.
│ if (type & PERF_SAMPLE_IDENTIFIER) {
│ ↓ jne 508
│ data->id = *array;
│ array++;
│ }
This option works with tui, stdio2 browsers.
annotate.show_nr_jumps
Let’s see a part of assembly code.
│1382: movb $0x1,-0x270(%rbp)
If use this, the number of branches jumping to that address can be printed as below. Default is 'false'.
│1 1382: movb $0x1,-0x270(%rbp)
This option works with tui, stdio2 browsers.
annotate.show_total_period
To compare two records on an instruction base, with this
option provided, display total number of samples that belong to a line in
assembly code. If this option is true, total periods are printed
instead of percent values as below.
302 │ mov %eax,%eax
But if this option is 'false', percent values for overhead are printed i.e. Default is 'false'.
99.93 │ mov %eax,%eax
This option works with tui, stdio2, stdio browsers.
annotate.show_nr_samples
By default perf annotate shows percentage of samples.
This option can be used to print absolute number of samples. Ex, when set as
false:
Percent│
74.03 │ mov %fs:0x28,%rax
When set as true:
Samples│
6 │ mov %fs:0x28,%rax
This option works with tui, stdio2, stdio browsers.
annotate.offset_level
Default is 1, meaning just jump targets will have
offsets show right beside the instruction. When set to 2 call
instructions will also have its offsets shown, 3 or higher will show offsets
for all instructions.
This option works with tui, stdio2 browsers.
annotate.demangle
Demangle symbol names to human readable form. Default is
true.
annotate.demangle_kernel
Demangle kernel symbol names to human readable form.
Default is true.
hist.*, hist.percentage
This option control the way to calculate overhead of
filtered entries - that means the value of this option is effective only if
there’s a filter (by comm, dso or symbol name). Suppose a following
example:
Overhead Symbols ........ .......
33.33% foo
33.33% bar
33.33% baz
This is an original overhead and we'll filter out the first 'foo' entry. The value of 'relative' would increase the overhead of 'bar' and 'baz' to 50.00% for each, while 'absolute' would show their current overhead (33.33%).
ui.*, ui.show-headers
This option controls display of column headers (like
Overhead and Symbol) in report and top. If this
option is false, they are hidden. This option is only applied to TUI.
call-graph.*
The following controls the handling of call-graphs
(obtained via the -g/--call-graph options).
call-graph.record-mode
The mode for user space can be fp (frame pointer),
dwarf and lbr. The value dwarf is effective only if
libunwind (or a recent version of libdw) is present on the system; the value
lbr only works for certain cpus. The method for kernel space is
controlled not by this option but by the kernel config
(CONFIG_UNWINDER_*).
call-graph.dump-size
The size of stack to dump in order to do post-unwinding.
Default is 8192 (byte). When using dwarf into record-mode, the default size
will be used if omitted.
call-graph.print-type
The print-types can be graph (graph absolute), fractal
(graph relative), flat and folded. This option controls a way to show overhead
for each callchain entry. Suppose a following example.
Overhead Symbols ........ .......
40.00% foo
|
---foo
|
|--50.00%--bar
| main
|
--50.00%--baz
main
This output is a 'fractal' format. The 'foo' came from 'bar' and 'baz' exactly half and half so 'fractal' shows 50.00% for each (meaning that it assumes 100% total overhead of 'foo').
The 'graph' uses absolute overhead value of 'foo' as total so each of 'bar' and 'baz' callchain will have 20.00% of overhead. If 'flat' is used, single column and linear exposure of call chains. 'folded' mean call chains are displayed in a line, separated by semicolons.
call-graph.order
This option controls print order of callchains. The
default is callee which means callee is printed at top and then
followed by its caller and so on. The caller prints it in reverse
order.
If this option is not set and report.children or top.children is set to true (or the equivalent command line option is given), the default value of this option is changed to 'caller' for the execution of 'perf report' or 'perf top'. Other commands will still default to 'callee'.
call-graph.sort-key
The callchains are merged if they contain same
information. The sort-key option determines a way to compare the callchains. A
value of sort-key can be function or address. The default
is function.
call-graph.threshold
When there’re many callchains it’d print
tons of lines. So perf omits small callchains under a certain overhead
(threshold) and this option control the threshold. Default is 0.5 (%). The
overhead is calculated by value depends on call-graph.print-type.
call-graph.print-limit
This is a maximum number of lines of callchain printed
for a single histogram entry. Default is 0 which means no limitation.
report.*, report.sort_order
Allows changing the default sort order from
"comm,dso,symbol" to some other default, for instance
"sym,dso" may be more fitting for kernel developers.
report.percent-limit
This one is mostly the same as call-graph.threshold but
works for histogram entries. Entries having an overhead lower than this
percentage will not be printed. Default is 0. If percent-limit is
10, only entries which have more than 10% of overhead will be
printed.
report.queue-size
This option sets up the maximum allocation size of the
internal event queue for ordering events. Default is 0, meaning no
limit.
report.children
Children means functions called from another
function. If this option is true, perf report cumulates callchains of
children and show (accumulated) total overhead as well as Self
overhead. Please refer to the perf report manual. The default is
true.
report.group
This option is to show event group information together.
Example output with this turned on, notice that there is one column per event
in the group, ref-cycles and cycles:
# group: {ref-cycles,cycles}
# ========
#
# Samples: 7K of event 'anon group { ref-cycles, cycles }'
# Event count (approx.): 6876107743
#
# Overhead Command Shared Object Symbol
# ................ ....... ................. ...................
#
99.84% 99.76% noploop noploop [.] main
0.07% 0.00% noploop ld-2.15.so [.] strcmp
0.03% 0.00% noploop [kernel.kallsyms] [k] timerqueue_del
report.skip-empty
This option can change default stat behavior with empty
results. If it’s set true, perf report --stat will not show 0
stats.
top.*, top.children
Same as report.children. So if it is enabled, the
output of top command will have Children overhead column as well
as Self overhead column by default. The default is true.
top.call-graph
This is identical to call-graph.record-mode,
except it is applicable only for top subcommand. This option ONLY setup
the unwind method. To enable perf top to actually use it, the command
line option -g must be specified.
man.*, man.viewer
This option can assign a tool to view manual pages when
help subcommand was invoked. Supported tools are man,
woman (with emacs client) and konqueror. Default is man.
New man viewer tool can be also added using 'man.<tool>.cmd' or use different path using 'man.<tool>.path' config option.
pager.*, pager.<subcommand>
When the subcommand is run on stdio, determine whether it
uses pager or not based on this value. Default is unspecified.
kmem.*, kmem.default
This option decides which allocator is to be analyzed if
neither --slab nor --page option is used. Default is
slab.
record.*, record.build-id
This option can be cache, no-cache,
skip or mmap. cache is to post-process data and
save/update the binaries into the build-id cache (in ~/.debug). This is the
default. But if this option is no-cache, it will not update the
build-id cache. skip skips post-processing and does not update the
cache. mmap skips post-processing and reads build-ids from MMAP
events.
record.call-graph
This is identical to call-graph.record-mode,
except it is applicable only for record subcommand. This option ONLY
setup the unwind method. To enable perf record to actually use it, the
command line option -g must be specified.
record.aio
Use n control blocks in asynchronous (Posix AIO)
trace writing mode (n default: 1, max: 4).
diff.*, diff.order
This option sets the number of columns to sort the
result. The default is 0, which means sorting by baseline. Setting it to 1
will sort the result by delta (or other compute method selected).
diff.compute
This options sets the method for computing the diff
result. Possible values are delta, delta-abs, ratio and
wdiff. Default is delta.
trace.*, trace.add_events
Allows adding a set of events to add to the ones
specified by the user, or use as a default one if none was specified. The
initial use case is to add augmented_raw_syscalls.o to activate the perf
trace logic that looks for syscall pointer contents after the normal
tracepoint payload.
trace.args_alignment
Number of columns to align the argument list, default is
70, use 40 for the strace default, zero to no alignment.
trace.no_inherit
Do not follow children threads.
trace.show_arg_names
Should syscall argument names be printed? If not then
trace.show_zeros will be set.
trace.show_duration
Show syscall duration.
trace.show_prefix
If set to yes will show common string prefixes in
tables. The default is to remove the common prefix in things like
"MAP_SHARED", showing just "SHARED".
trace.show_timestamp
Show syscall start timestamp.
trace.show_zeros
Do not suppress syscall arguments that are equal to
zero.
trace.tracepoint_beautifiers
Use "libtraceevent" to use that library to
augment the tracepoint arguments, "libbeauty", the default, to use
the same argument beautifiers used in the strace-like sys_enter+sys_exit
lines.
ftrace.*, ftrace.tracer
Can be used to select the default tracer when neither -G
nor -F option is not specified. Possible values are function and
function_graph.
llvm.*, llvm.clang-path
Path to clang. If omit, search it from $PATH.
llvm.clang-bpf-cmd-template
Cmdline template. Below lines show its default value.
Environment variable is used to pass options. "$CLANG_EXEC
-DKERNEL -DNR_CPUS=$NR_CPUS "\
"-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \ "$CLANG_OPTIONS
$PERF_BPF_INC_OPTIONS $KERNEL_INC_OPTIONS " \ "-Wno-unused-value
-Wno-pointer-sign " \ "-working-directory $WORKING_DIR " \
"-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -O2 -o -
$LLVM_OPTIONS_PIPE"
llvm.clang-opt
Options passed to clang.
llvm.kbuild-dir
kbuild directory. If not set, use /lib/modules/uname
-r/build. If set to "" deliberately, skip kernel header
auto-detector.
llvm.kbuild-opts
Options passed to make when detecting kernel
header options.
llvm.dump-obj
Enable perf dump BPF object files compiled by LLVM.
llvm.opts
Options passed to llc.
samples.*, samples.context
Define how many ns worth of time to show around samples
in perf report sample context browser.
scripts.*
Any option defines a script that is added to the scripts
menu in the interactive perf browser and whose output is displayed. The name
of the option is the name, the value is a script command line. The script gets
the same options passed as a full perf script, in particular -i perfdata file,
--cpu, --tid
convert.*, convert.queue-size
Limit the size of ordered_events queue, so we could
control allocation size of perf data files without proper finished round
events.
stat.*, stat.big-num
(boolean) Change the default for "--big-num".
To make "--no-big-num" the default, set
"stat.big-num=false".
intel-pt.*, intel-pt.cache-divisor, intel-pt.mispred-all
If set, Intel PT decoder will set the mispred flag on all
branches.
intel-pt.max-loops
If set and non-zero, the maximum number of unconditional
branches decoded without consuming any trace packets. If the maximum is
exceeded there will be a "Never-ending loop" error. The default is
100000.
auxtrace.*, auxtrace.dumpdir
s390 only. The directory to save the auxiliary trace
buffer can be changed using this option. Ex, auxtrace.dumpdir=/tmp. If the
directory does not exist or has the wrong file type, the current directory is
used.
daemon.*, daemon.base
Base path for daemon data. All sessions data are stored
under this path.
session-<NAME>.*, session-<NAME>.run
Defines new record session for daemon. The value is
record’s command line without the record keyword.
SEE ALSO¶
| 06/14/2024 | perf |