PERF-RECORD(1) perf Manual PERF-RECORD(1)
NAME
perf-record - Run a command and record its profile into perf.data
SYNOPSIS
perf record [-e | --event=EVENT] [-a]
perf record [-e | --event=EVENT] [-a] -- []
DESCRIPTION
This command runs a command and gathers a performance counter profile from it, into perf.data - without displaying
anything.
This file can then be inspected later on, using perf report.
OPTIONS
...
Any command you can specify in a shell.
-e, --event=
Select the PMU event. Selection can be:
• a symbolic event name (use perf list to list all events)
• a raw PMU event in the form of rN where N is a hexadecimal value that represents the raw register encoding
with the layout of the event control registers as described by entries in
/sys/bus/event_source/devices/cpu/format/*.
• a symbolic or raw PMU event followed by an optional colon and a list of event modifiers, e.g., cpu-cycles:p.
See the perf-list(1) man page for details on event modifiers.
• a symbolically formed PMU event like pmu/param1=0x3,param2/ where param1, param2, etc are defined as formats
for the PMU in /sys/bus/event_source/devices//format/*.
• a symbolically formed event like pmu/config=M,config1=N,config3=K/
where M, N, K are numbers (in decimal, hex, octal format). Acceptable
values for each of 'config', 'config1' and 'config2' are defined by
corresponding entries in /sys/bus/event_source/devices//format/*
param1 and param2 are defined as formats for the PMU in:
/sys/bus/event_source/devices//format/*
There are also some parameters which are not defined in ...//format/*.
These params can be used to overload default config values per event.
Here are some common parameters:
- 'period': Set event sampling period
- 'freq': Set event sampling frequency
- 'time': Disable/enable time stamping. Acceptable values are 1 for
enabling time stamping. 0 for disabling time stamping.
The default is 1.
- 'call-graph': Disable/enable callgraph. Acceptable str are "fp" for
FP mode, "dwarf" for DWARF mode, "lbr" for LBR mode and
"no" for disable callgraph.
- 'stack-size': user stack size for dwarf mode
- 'name' : User defined event name. Single quotes (') may be used to
escape symbols in the name from parsing by shell and tool
like this: name=\'CPU_CLK_UNHALTED.THREAD:cmask=0x1\'.
- 'aux-output': Generate AUX records instead of events. This requires
that an AUX area event is also provided.
- 'aux-action': "pause" or "resume" to pause or resume an AUX
area event (the group leader) when this event occurs.
"start-paused" on an AUX area event itself, will
start in a paused state.
- 'aux-sample-size': Set sample size for AUX area sampling. If the
'--aux-sample' option has been used, set aux-sample-size=0 to disable
AUX area sampling for the event.
See the linkperf:perf-list[1] man page for more parameters.
Note: If user explicitly sets options which conflict with the params,
the value set by the parameters will be overridden.
Also not defined in ...//format/* are PMU driver specific
configuration parameters. Any configuration parameter preceded by
the letter '@' is not interpreted in user space and sent down directly
to the PMU driver. For example:
perf record -e some_event/@cfg1,@cfg2=config/ ...
will see 'cfg1' and 'cfg2=config' pushed to the PMU driver associated
with the event for further processing. There is no restriction on
what the configuration parameters are, as long as their semantic is
understood and supported by the PMU driver.
• a hardware breakpoint event in the form of \mem:addr[/len][:access] where addr is the address in memory you
want to break in. Access is the memory access type (read, write, execute) it can be passed as follows:
\mem:addr[:[r][w][x]]. len is the range, number of bytes from specified addr, which the breakpoint will
cover. If you want to profile read-write accesses in 0x1000, just set mem:0x1000:rw. If you want to profile
write accesses in [0x1000~1008), just set mem:0x1000/8:w.
• a group of events surrounded by a pair of brace ("{event1,event2,...}"). Each event is separated by commas
and the group should be quoted to prevent the shell interpretation. You also need to use --group on "perf
report" to view group events together.
--filter=
Event filter. This option should follow an event selector (-e). If the event is a tracepoint, the filter string
will be parsed by the kernel. If the event is a hardware trace PMU (e.g. Intel PT or CoreSight), it’ll be
processed as an address filter. Otherwise it means a general filter using BPF which can be applied for any kind
of event.
• tracepoint filters
In the case of tracepoints, multiple '--filter' options are combined
using '&&'.
• address filters
A hardware trace PMU advertises its ability to accept a number of
address filters by specifying a non-zero value in
/sys/bus/event_source/devices//nr_addr_filters.
Address filters have the format:
filter|start|stop|tracestop [/ ] [@]
Where:
- 'filter': defines a region that will be traced.
- 'start': defines an address at which tracing will begin.
- 'stop': defines an address at which tracing will stop.
- 'tracestop': defines a region in which tracing will stop.
is the name of the object file, is the offset to the
code to trace in that file, and is the size of the region to
trace. 'start' and 'stop' filters need not specify a .
If no object file is specified then the kernel is assumed, in which case
the start address must be a current kernel memory address.
can also be specified by providing the name of a symbol. If the
symbol name is not unique, it can be disambiguated by inserting #n where
'n' selects the n'th symbol in address order. Alternately #0, #g or #G
select only a global symbol. can also be specified by providing
the name of a symbol, in which case the size is calculated to the end
of that symbol. For 'filter' and 'tracestop' filters, if is
omitted and is a symbol, then the size is calculated to the end
of that symbol.
If is omitted and is '*', then the start and size will
be calculated from the first and last symbols, i.e. to trace the whole
file.
If symbol names (or '*') are provided, they must be surrounded by white
space.
The filter passed to the kernel is not necessarily the same as entered.
To see the filter that is passed, use the -v option.
The kernel may not be able to configure a trace region if it is not
within a single mapping. MMAP events (or /proc//maps) can be
examined to determine if that is a possibility.
Multiple filters can be separated with space or comma.
• bpf filters
A BPF filter can access the sample data and make a decision based on the
data. Users need to set an appropriate sample type to use the BPF
filter. BPF filters need root privilege.
The sample data field can be specified in lower case letter. Multiple
filters can be separated with comma. For example,
--filter 'period > 1000, cpu == 1'
or
--filter 'mem_op == load || mem_op == store, mem_lvl > l1'
The former filter only accept samples with period greater than 1000 AND
CPU number is 1. The latter one accepts either load and store memory
operations but it should have memory level above the L1. Since the
mem_op and mem_lvl fields come from the (memory) data_source, it'd only
work with some events which set the data_source field.
Also user should request to collect that information (with -d option in
the above case). Otherwise, the following message will be shown.
$ sudo perf record -e cycles --filter 'mem_op == load'
Error: cycles event does not have PERF_SAMPLE_DATA_SRC
Hint: please add -d option to perf record.
failed to set filter "BPF" on event cycles with 22 (Invalid argument)
Essentially the BPF filter expression is:
(("," | "||") )*
The can be one of:
ip, id, tid, pid, cpu, time, addr, period, txn, weight, phys_addr,
code_pgsz, data_pgsz, weight1, weight2, weight3, ins_lat, retire_lat,
p_stage_cyc, mem_op, mem_lvl, mem_snoop, mem_remote, mem_lock,
mem_dtlb, mem_blk, mem_hops, uid, gid
The can be one of:
==, !=, >, >=, <, <=, &
The can be one of:
(for any term)
na, load, store, pfetch, exec (for mem_op)
l1, l2, l3, l4, cxl, io, any_cache, lfb, ram, pmem (for mem_lvl)
na, none, hit, miss, hitm, fwd, peer (for mem_snoop)
remote (for mem_remote)
na, locked (for mem_locked)
na, l1_hit, l1_miss, l2_hit, l2_miss, any_hit, any_miss, walk, fault (for mem_dtlb)
na, by_data, by_addr (for mem_blk)
hops0, hops1, hops2, hops3 (for mem_hops)
--exclude-perf
Don’t record events issued by perf itself. This option should follow an event selector (-e) which selects
tracepoint event(s). It adds a filter expression common_pid != $PERFPID to filters. If other --filter exists, the
new filter expression will be combined with them by &&.
--latency
Enable data collection for latency profiling. Use perf report --latency for latency-centric profile.
-a, --all-cpus
System-wide collection from all CPUs (default if no target is specified).
-p, --pid=
Record events on existing process ID (comma separated list).
-t, --tid=
Record events on existing thread ID (comma separated list). This option also disables inheritance by default.
Enable it by adding --inherit.
-u, --uid=
Record events in threads owned by uid. Name or number.
-r, --realtime=
Collect data with this RT SCHED_FIFO priority.
--no-buffering
Collect data without buffering.
-c, --count=
Event period to sample.
-o, --output=
Output file name.
-i, --no-inherit
Child tasks do not inherit counters.
-F, --freq=
Profile at this frequency. Use max to use the currently maximum allowed frequency, i.e. the value in the
kernel.perf_event_max_sample_rate sysctl. Will throttle down to the currently maximum allowed frequency. See
--strict-freq.
--strict-freq
Fail if the specified frequency can’t be used.
-m, --mmap-pages=
Number of mmap data pages (must be a power of two) or size specification in bytes with appended unit character -
B/K/M/G. The size is rounded up to the nearest power-of-two page value. By adding a comma, an additional
parameter with the same semantics used for the normal mmap areas can be specified for AUX tracing area.
-g
Enables call-graph (stack chain/backtrace) recording for both kernel space and user space.
--call-graph
Setup and enable call-graph (stack chain/backtrace) recording, implies -g. Default is "fp" (for user space).
The unwinding method used for kernel space is dependent on the
unwinder used by the active kernel configuration, i.e
CONFIG_UNWINDER_FRAME_POINTER (fp) or CONFIG_UNWINDER_ORC (orc)
Any option specified here controls the method used for user space.
Valid options are "fp" (frame pointer), "dwarf" (DWARF's CFI -
Call Frame Information) or "lbr" (Hardware Last Branch Record
facility).
In some systems, where binaries are build with gcc
--fomit-frame-pointer, using the "fp" method will produce bogus
call graphs, using "dwarf", if available (perf tools linked to
the libunwind or libdw library) should be used instead.
Using the "lbr" method doesn't require any compiler options. It
will produce call graphs from the hardware LBR registers. The
main limitation is that it is only available on new Intel
platforms, such as Haswell. It can only get user call chain. It
doesn't work with branch stack sampling at the same time.
When "dwarf" recording is used, perf also records (user) stack dump
when sampled. Default size of the stack dump is 8192 (bytes).
User can change the size by passing the size after comma like
"--call-graph dwarf,4096".
When "fp" recording is used, perf tries to save stack entries
up to the number specified in sysctl.kernel.perf_event_max_stack
by default. User can change the number by passing it after comma
like "--call-graph fp,32".
Also "defer" can be used with "fp" (like "--call-graph fp,defer") to
enable deferred user callchain which will collect user-space callchains
when the thread returns to the user space.
-q, --quiet
Don’t print any warnings or messages, useful for scripting.
-v, --verbose
Be more verbose (show counter open errors, etc).
-s, --stat
Record per-thread event counts. Use it with perf report -T to see the values.
-d, --data
Record the sample virtual addresses. Implies --sample-mem-info and --data-mmap.
--phys-data
Record the sample physical addresses.
--data-page-size
Record the sampled data address data page size.
--code-page-size
Record the sampled code address (ip) page size
-T, --timestamp
Record the sample timestamps. Use it with perf report -D to see the timestamps, for instance.
-P, --period
Record the sample period.
--sample-cpu
Record the sample cpu.
--sample-identifier
Record the sample identifier i.e. PERF_SAMPLE_IDENTIFIER bit set in the sample_type member of the struct
perf_event_attr argument to the perf_event_open system call.
--sample-mem-info
Record the sample data source information for memory operations. It requires hardware supports and may work on
specific events only. Please consider using perf mem record instead if you’re not sure.
-n, --no-samples
Don’t sample.
-R, --raw-samples
Collect raw sample records from all opened counters (default for tracepoint counters).
-C, --cpu
Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a comma-separated list with
no space: 0,1. Ranges of CPUs are specified with -: 0-2. In per-thread mode with inheritance mode on (default),
samples are captured only when the thread executes on the designated CPUs. Default is to monitor all CPUs.
User space tasks can migrate between CPUs, so when tracing selected CPUs, a dummy event is created to track sideband
for all CPUs.
-B, --no-buildid
Do not save the build ids of binaries in the perf.data files. This skips post processing after recording, which
sometimes makes the final step in the recording process to take a long time, as it needs to process all events
looking for mmap records. The downside is that it can misresolve symbols if the workload binaries used when
recording get locally rebuilt or upgraded, because the only key available in this case is the pathname. You can
also set the "record.build-id" config variable to 'skip to have this behaviour permanently.
-N, --no-buildid-cache
Do not update the buildid cache. This saves some overhead in situations where the information in the perf.data
file (which includes buildids) is sufficient. You can also set the "record.build-id" config variable to no-cache
to have the same effect.
-G name,..., --cgroup name,...
monitor only in the container (cgroup) called "name". This option is available only in per-cpu mode. The cgroup
filesystem must be mounted. All threads belonging to container "name" are monitored when they run on the
monitored CPUs. Multiple cgroups can be provided. Each cgroup is applied to the corresponding event, i.e., first
cgroup to first event, second cgroup to second event and so on. It is possible to provide an empty cgroup
(monitor all the time) using, e.g., -G foo,,bar. Cgroups must have corresponding events, i.e., they always refer
to events defined earlier on the command line. If the user wants to track multiple events for a specific cgroup,
the user can use -e e1 -e e2 -G foo,foo or just use -e e1 -e e2 -G foo.
If wanting to monitor, say, cycles for a cgroup and also for system wide, this command line can be used: perf stat -e
cycles -G cgroup_name -a -e cycles.
-b, --branch-any
Enable taken branch stack sampling. Any type of taken branch may be sampled. This is a shortcut for
--branch-filter any. See --branch-filter for more infos.
-j, --branch-filter
Enable taken branch stack sampling. Each sample captures a series of consecutive taken branches. The number of
branches captured with each sample depends on the underlying hardware, the type of branches of interest, and the
executed code. It is possible to select the types of branches captured by enabling filters. The following filters
are defined:
• any: any type of branches
• any_call: any function call or system call
• any_ret: any function return or system call return
• ind_call: any indirect branch
• ind_jmp: any indirect jump
• call: direct calls, including far (to/from kernel) calls
• u: only when the branch target is at the user level
• k: only when the branch target is in the kernel
• hv: only when the target is at the hypervisor level
• in_tx: only when the target is in a hardware transaction
• no_tx: only when the target is not in a hardware transaction
• abort_tx: only when the target is a hardware transaction abort
• cond: conditional branches
• stack: save call stack
• no_flags: don’t save branch flags e.g prediction, misprediction etc
• no_cycles: don’t save branch cycles
• hw_index: save branch hardware index
• save_type: save branch type during sampling in case binary is not available later For the platforms with
Intel Arch LBR support (12th-Gen+ client or 4th-Gen Xeon+ server), the save branch type is unconditionally
enabled when the taken branch stack sampling is enabled.
• priv: save privilege state during sampling in case binary is not available later
• counter: save occurrences of the event since the last branch entry. Currently, the feature is only supported
by a newer CPU, e.g., Intel Sierra Forest and later platforms. An error out is expected if it’s used on the
unsupported kernel or CPUs.
The option requires at least one branch type among any, any_call, any_ret, ind_call, cond. The privilege levels
may be omitted, in which case, the privilege levels of the associated event are applied to the branch filter.
Both kernel (k) and hypervisor (hv) privilege levels are subject to permissions. When sampling on multiple
events, branch stack sampling is enabled for all the sampling events. The sampled branch type is the same for all
events. The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k Note that
this feature may not be available on all processors.
-W, --weight
Enable weightened sampling. An additional weight is recorded per sample and can be displayed with the weight and
local_weight sort keys. This currently works for TSX abort events and some memory events in precise mode on
modern Intel CPUs.
--namespaces
Record events of type PERF_RECORD_NAMESPACES. This enables cgroup_id sort key.
--all-cgroups
Record events of type PERF_RECORD_CGROUP. This enables cgroup sort key.
--transaction
Record transaction flags for transaction related events.
--per-thread
Use per-thread mmaps. By default per-cpu mmaps are created. This option overrides that and uses per-thread mmaps.
A side-effect of that is that inheritance is automatically disabled. --per-thread is ignored with a warning if
combined with -a or -C options.
-D, --delay=
After starting the program, wait msecs before measuring (-1: start with events disabled), or enable events only
for specified ranges of msecs (e.g. -D 10-20,30-40 means wait 10 msecs, enable for 10 msecs, wait 10 msecs,
enable for 10 msecs, then stop). Note, delaying enabling of events is useful to filter out the startup phase of
the program, which is often very different.
-I, --intr-regs
Capture machine state (registers) at interrupt, i.e., on counter overflows for each sample. List of captured
registers depends on the architecture. This option is off by default. It is possible to select the registers to
sample using their symbolic names, e.g. on x86, ax, si. To list the available registers use --intr-regs=\?. To
name registers, pass a comma separated list such as --intr-regs=ax,bx. The list of register is architecture
dependent.
--user-regs
Similar to -I, but capture user registers at sample time. To list the available user registers use
--user-regs=\?.
--running-time
Record running and enabled time for read events (:S)
-k, --clockid
Sets the clock id to use for the various time fields in the perf_event_type records. See clock_gettime(). In
particular CLOCK_MONOTONIC and CLOCK_MONOTONIC_RAW are supported, some events might also allow CLOCK_BOOTTIME,
CLOCK_REALTIME and CLOCK_TAI.
-S, --snapshot
Select AUX area tracing Snapshot Mode. This option is valid only with an AUX area tracing event. Optionally,
certain snapshot capturing parameters can be specified in a string that follows this option:
• e: take one last snapshot on exit; guarantees that there is at least one snapshot in the output file;
• : if the PMU supports this, specify the desired snapshot size.
In Snapshot Mode trace data is captured only when signal SIGUSR2 is received and on exit if the above e option is
given.
--aux-sample[=OPTIONS]
Select AUX area sampling. At least one of the events selected by the -e option must be an AUX area event. Samples
on other events will be created containing data from the AUX area. Optionally sample size may be specified,
otherwise it defaults to 4KiB.
--proc-map-timeout
When processing pre-existing threads /proc/XXX/mmap, it may take a long time, because the file may be huge. A
time out is needed in such cases. This option sets the time out limit. The default value is 500 ms.
--switch-events
Record context switch events i.e. events of type PERF_RECORD_SWITCH or PERF_RECORD_SWITCH_CPU_WIDE. In some cases
(e.g. Intel PT, CoreSight or Arm SPE) switch events will be enabled automatically, which can be suppressed by by
the option --no-switch-events.
--vmlinux=PATH
Specify vmlinux path which has debuginfo. (enabled when BPF prologue is on)
--buildid-all
Record build-id of all DSOs regardless whether it’s actually hit or not.
--buildid-mmap
Legacy record build-id in map events option which is now the default. Behaves indentically to --no-buildid.
Disable with --no-buildid-mmap.
--aio[=n]
Use control blocks in asynchronous (Posix AIO) trace writing mode (default: 1, max: 4). Asynchronous mode is
supported only when linking Perf tool with libc library providing implementation for Posix AIO API.
--affinity=mode
Set affinity mask of trace reading thread according to the policy defined by mode value:
• node - thread affinity mask is set to NUMA node cpu mask of the processed mmap buffer
• cpu - thread affinity mask is set to cpu of the processed mmap buffer
--mmap-flush=number
Specify minimal number of bytes that is extracted from mmap data pages and processed for output. One can specify
the number using B/K/M/G suffixes.
The maximal allowed value is a quarter of the size of mmaped data pages.
The default option value is 1 byte which means that every time that the output writing thread finds some new data in
the mmaped buffer the data is extracted, possibly compressed (-z) and written to the output, perf.data or pipe.
Larger data chunks are compressed more effectively in comparison to smaller chunks so extraction of larger chunks
from the mmap data pages is preferable from the perspective of output size reduction.
Also at some cases executing less output write syscalls with bigger data size can take less time than executing more
output write syscalls with smaller data size thus lowering runtime profiling overhead.
-z, --compression-level[=n]
Produce compressed trace using specified level n (default: 1 - fastest compression, 22 - smallest trace)
--all-kernel
Configure all used events to run in kernel space.
--all-user
Configure all used events to run in user space.
--kernel-callchains
Collect callchains only from kernel space. I.e. this option sets perf_event_attr.exclude_callchain_user to 1.
--user-callchains
Collect callchains only from user space. I.e. this option sets perf_event_attr.exclude_callchain_kernel to 1.
Don’t use both --kernel-callchains and --user-callchains at the same time or no callchains will be collected.
--timestamp-filename Append timestamp to output file name.
--timestamp-boundary
Record timestamp boundary (time of first/last samples).
--switch-output[=mode]
Generate multiple perf.data files, timestamp prefixed, switching to a new one based on mode value:
• "signal" - when receiving a SIGUSR2 (default value) or
• - when reaching the size threshold, size is expected to be a number with appended unit character -
B/K/M/G
•