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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | STAT RECORD | STAT REPORT | EXAMPLES | TIMINGS | CSV FORMAT | INTEL HYBRID SUPPORT | JSON FORMAT | SEE ALSO | COLOPHON |
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PERF-STAT(1) perf Manual PERF-STAT(1)
perf-stat - Run a command and gather performance counter
statistics
perf stat [-e <EVENT> | --event=EVENT] [-a] <command>
perf stat [-e <EVENT> | --event=EVENT] [-a] -- <command> [<options>]
perf stat [-e <EVENT> | --event=EVENT] [-a] record [-o file] -- <command> [<options>]
perf stat report [-i file]
This command runs a command and gathers performance counter
statistics from it.
<command>...
Any command you can specify in a shell.
record
See STAT RECORD.
report
See STAT REPORT.
-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 event like pmu/param1=0x3,param2/
where param1 and param2 are defined as formats for the PMU
in /sys/bus/event_source/devices/<pmu>/format/*
'percore' is a event qualifier that sums up the event counts for both
hardware threads in a core. For example:
perf stat -A -a -e cpu/event,percore=1/,otherevent ...
• a symbolically formed event like
pmu/config=M,config1=N,config2=K/ where M, N, K are
numbers (in decimal, hex, octal format). Acceptable values
for each of config, config1 and config2 parameters are
defined by corresponding entries in
/sys/bus/event_source/devices/<pmu>/format/*
Note that the last two syntaxes support prefix and glob matching in
the PMU name to simplify creation of events across multiple instances
of the same type of PMU in large systems (e.g. memory controller PMUs).
Multiple PMU instances are typical for uncore PMUs, so the prefix
'uncore_' is also ignored when performing this match.
-i, --no-inherit
child tasks do not inherit counters
-p, --pid=<pid>
stat events on existing process id (comma separated list)
-t, --tid=<tid>
stat events on existing thread id (comma separated list)
-b, --bpf-prog
stat events on existing bpf program id (comma separated list),
requiring root rights. bpftool-prog could be used to find
program id all bpf programs in the system. For example:
# bpftool prog | head -n 1
17247: tracepoint name sys_enter tag 192d548b9d754067 gpl
# perf stat -e cycles,instructions --bpf-prog 17247 --timeout 1000
Performance counter stats for 'BPF program(s) 17247':
85,967 cycles
28,982 instructions # 0.34 insn per cycle
1.102235068 seconds time elapsed
--bpf-counters
Use BPF programs to aggregate readings from perf_events. This
allows multiple perf-stat sessions that are counting the same
metric (cycles, instructions, etc.) to share hardware
counters. To use BPF programs on common events by default, use
"perf config stat.bpf-counter-events=<list_of_events>".
--bpf-attr-map
With option "--bpf-counters", different perf-stat sessions
share information about shared BPF programs and maps via a
pinned hashmap. Use "--bpf-attr-map" to specify the path of
this pinned hashmap. The default path is
/sys/fs/bpf/perf_attr_map.
-a, --all-cpus
system-wide collection from all CPUs (default if no target is
specified)
--no-scale
Don’t scale/normalize counter values
-d, --detailed
print more detailed statistics, can be specified up to 3 times
-d: detailed events, L1 and LLC data cache
-d -d: more detailed events, dTLB and iTLB events
-d -d -d: very detailed events, adding prefetch events
-r, --repeat=<n>
repeat command and print average + stddev (max: 100). 0 means
forever.
-B, --big-num
print large numbers with thousands' separators according to
locale. Enabled by default. Use "--no-big-num" to disable.
Default setting can be changed with "perf config
stat.big-num=false".
-C, --cpu=
Count 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, this
option is ignored. The -a option is still necessary to
activate system-wide monitoring. Default is to count on all
CPUs.
-A, --no-aggr
Do not aggregate counts across all monitored CPUs.
-n, --null
null run - Don’t start any counters.
This can be useful to measure just elapsed wall-clock time - or to
assess the raw overhead of perf stat itself, without running any
counters.
-v, --verbose
be more verbose (show counter open errors, etc)
-x SEP, --field-separator SEP
print counts using a CSV-style output to make it easy to
import directly into spreadsheets. Columns are separated by
the string specified in SEP.
--table
Display time for each run (-r option), in a table format,
e.g.:
$ perf stat --null -r 5 --table perf bench sched pipe
Performance counter stats for 'perf bench sched pipe' (5 runs):
# Table of individual measurements:
5.189 (-0.293) #
5.189 (-0.294) #
5.186 (-0.296) #
5.663 (+0.181) ##
6.186 (+0.703) ####
# Final result:
5.483 +- 0.198 seconds time elapsed ( +- 3.62% )
-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.
--for-each-cgroup name
Expand event list for each cgroup in "name" (allow multiple
cgroups separated by comma). It also support regex patterns to
match multiple groups. This has same effect that repeating -e
option and -G option for each event x name. This option cannot
be used with -G/--cgroup option.
-o file, --output file
Print the output into the designated file.
--append
Append to the output file designated with the -o option.
Ignored if -o is not specified.
--log-fd
Log output to fd, instead of stderr. Complementary to
--output, and mutually exclusive with it. --append may be used
here. Examples: 3>results perf stat --log-fd 3 -- $cmd
3>>results perf stat --log-fd 3 --append -- $cmd
--control=fifo:ctl-fifo[,ack-fifo], --control=fd:ctl-fd[,ack-fd]
ctl-fifo / ack-fifo are opened and used as ctl-fd / ack-fd as
follows. Listen on ctl-fd descriptor for command to control
measurement (enable: enable events, disable: disable events).
Measurements can be started with events disabled using
--delay=-1 option. Optionally send control command completion
(ack\n) to ack-fd descriptor to synchronize with the
controlling process. Example of bash shell script to enable
and disable events during measurements:
#!/bin/bash
ctl_dir=/tmp/
ctl_fifo=${ctl_dir}perf_ctl.fifo
test -p ${ctl_fifo} && unlink ${ctl_fifo}
mkfifo ${ctl_fifo}
exec {ctl_fd}<>${ctl_fifo}
ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo
test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo}
mkfifo ${ctl_ack_fifo}
exec {ctl_fd_ack}<>${ctl_ack_fifo}
perf stat -D -1 -e cpu-cycles -a -I 1000 \
--control fd:${ctl_fd},${ctl_fd_ack} \
\-- sleep 30 &
perf_pid=$!
sleep 5 && echo 'enable' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})"
sleep 10 && echo 'disable' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})"
exec {ctl_fd_ack}>&-
unlink ${ctl_ack_fifo}
exec {ctl_fd}>&-
unlink ${ctl_fifo}
wait -n ${perf_pid}
exit $?
--pre, --post
Pre and post measurement hooks, e.g.:
perf stat --repeat 10 --null --sync --pre make -s
O=defconfig-build/clean -- make -s -j64 O=defconfig-build/ bzImage
-I msecs, --interval-print msecs
Print count deltas every N milliseconds (minimum: 1ms) The
overhead percentage could be high in some cases, for instance
with small, sub 100ms intervals. Use with caution. example:
perf stat -I 1000 -e cycles -a sleep 5
If the metric exists, it is calculated by the counts generated in
this interval and the metric is printed after #.
--interval-count times
Print count deltas for fixed number of times. This option
should be used together with "-I" option. example: perf stat
-I 1000 --interval-count 2 -e cycles -a
--interval-clear
Clear the screen before next interval.
--timeout msecs
Stop the perf stat session and print count deltas after N
milliseconds (minimum: 10 ms). This option is not supported
with the "-I" option. example: perf stat --time 2000 -e cycles
-a
--metric-only
Only print computed metrics. Print them in a single line.
Don’t show any raw values. Not supported with --per-thread.
--per-socket
Aggregate counts per processor socket for system-wide mode
measurements. This is a useful mode to detect imbalance
between sockets. To enable this mode, use --per-socket in
addition to -a. (system-wide). The output includes the socket
number and the number of online processors on that socket.
This is useful to gauge the amount of aggregation.
--per-die
Aggregate counts per processor die for system-wide mode
measurements. This is a useful mode to detect imbalance
between dies. To enable this mode, use --per-die in addition
to -a. (system-wide). The output includes the die number and
the number of online processors on that die. This is useful to
gauge the amount of aggregation.
--per-cluster
Aggregate counts per processor cluster for system-wide mode
measurement. This is a useful mode to detect imbalance between
clusters. To enable this mode, use --per-cluster in addition
to -a. (system-wide). The output includes the cluster number
and the number of online processors on that cluster. This is
useful to gauge the amount of aggregation. The information of
cluster ID and related CPUs can be gotten from
/sys/devices/system/cpu/cpuX/topology/cluster_{id, cpus}.
--per-cache
Aggregate counts per cache instance for system-wide mode
measurements. By default, the aggregation happens for the
cache level at the highest index in the system. To specify a
particular level, mention the cache level alongside the option
in the format [Ll][1-9][0-9]*. For example: Using option
"--per-cache=l3" or "--per-cache=L3" will aggregate the
information at the boundary of the level 3 cache in the
system.
--per-core
Aggregate counts per physical processor for system-wide mode
measurements. This is a useful mode to detect imbalance
between physical cores. To enable this mode, use --per-core in
addition to -a. (system-wide). The output includes the core
number and the number of online logical processors on that
physical processor.
--per-thread
Aggregate counts per monitored threads, when monitoring
threads (-t option) or processes (-p option).
--per-node
Aggregate counts per NUMA nodes for system-wide mode
measurements. This is a useful mode to detect imbalance
between NUMA nodes. To enable this mode, use --per-node in
addition to -a. (system-wide).
-D msecs, --delay msecs
After starting the program, wait msecs before measuring (-1:
start with events disabled). This is useful to filter out the
startup phase of the program, which is often very different.
-T, --transaction
Print statistics of transactional execution if supported.
--metric-no-group
By default, events to compute a metric are placed in weak
groups. The group tries to enforce scheduling all or none of
the events. The --metric-no-group option places events outside
of groups and may increase the chance of the event being
scheduled - leading to more accuracy. However, as events may
not be scheduled together accuracy for metrics like
instructions per cycle can be lower - as both metrics may no
longer be being measured at the same time.
--metric-no-merge
By default metric events in different weak groups can be
shared if one group contains all the events needed by another.
In such cases one group will be eliminated reducing event
multiplexing and making it so that certain groups of metrics
sum to 100%. A downside to sharing a group is that the group
may require multiplexing and so accuracy for a small group
that need not have multiplexing is lowered. This option
forbids the event merging logic from sharing events between
groups and may be used to increase accuracy in this case.
--metric-no-threshold
Metric thresholds may increase the number of events necessary
to compute whether a metric has exceeded its threshold
expression. This may not be desirable, for example, as the
events can introduce multiplexing. This option disables the
adding of threshold expression events for a metric. However,
if there are sufficient events to compute the threshold then
the threshold is still computed and used to color the metric’s
computed value.
--quiet
Don’t print output, warnings or messages. This is useful with
perf stat record below to only write data to the perf.data
file.
Stores stat data into perf data file.
-o file, --output file
Output file name.
Reads and reports stat data from perf data file.
-i file, --input file
Input file name.
--per-socket
Aggregate counts per processor socket for system-wide mode
measurements.
--per-die
Aggregate counts per processor die for system-wide mode
measurements.
--per-cluster
Aggregate counts perf processor cluster for system-wide mode
measurements.
--per-cache
Aggregate counts per cache instance for system-wide mode
measurements. By default, the aggregation happens for the
cache level at the highest index in the system. To specify a
particular level, mention the cache level alongside the option
in the format [Ll][1-9][0-9]*. For example: Using option
"--per-cache=l3" or "--per-cache=L3" will aggregate the
information at the boundary of the level 3 cache in the
system.
--per-core
Aggregate counts per physical processor for system-wide mode
measurements.
-M, --metrics
Print metrics or metricgroups specified in a comma separated
list. For a group all metrics from the group are added. The
events from the metrics are automatically measured. See perf
list output for the possible metrics and metricgroups.
When threshold information is available for a metric, the
color red is used to signify a metric has exceeded a threshold
while green shows it hasn't. The default color means that
no threshold information was available or the threshold
couldn't be computed.
-A, --no-aggr, --no-merge
Do not aggregate/merge counts across monitored CPUs or PMUs.
When multiple events are created from a single event
specification, stat will, by default, aggregate the event counts
and show the result in a single row. This option disables that
behavior and shows the individual events and counts.
Multiple events are created from a single event specification
when:
1. PID monitoring isn’t requested and the system has more than
one CPU. For example, a system with 8 SMT threads will have
one event opened on each thread and aggregation is performed
across them.
2. Prefix or glob wildcard matching is used for the PMU name. For
example, multiple memory controller PMUs may exist typically
with a suffix of _0, _1, etc. By default the event counts will
all be combined if the PMU is specified without the suffix
such as uncore_imc rather than uncore_imc_0.
3. Aliases, which are listed immediately after the Kernel PMU
events by perf list, are used.
--hybrid-merge
Merge core event counts from all core PMUs. In hybrid or
big.LITTLE systems by default each core PMU will report
its count separately. This option forces core PMU counts
to be combined to give a behavior closer to having a
single CPU type in the system.
--topdown
Print top-down metrics supported by the CPU. This allows
to determine bottle necks in the CPU pipeline for CPU
bound workloads, by breaking the cycles consumed down into
frontend bound, backend bound, bad speculation and
retiring.
Frontend bound means that the CPU cannot fetch and decode
instructions fast enough. Backend bound means that computation or
memory access is the bottle neck. Bad Speculation means that the
CPU wasted cycles due to branch mispredictions and similar issues.
Retiring means that the CPU computed without an apparently
bottleneck. The bottleneck is only the real bottleneck if the
workload is actually bound by the CPU and not by something else.
For best results it is usually a good idea to use it with interval
mode like -I 1000, as the bottleneck of workloads can change
often.
This enables --metric-only, unless overridden with
--no-metric-only.
The following restrictions only apply to older Intel CPUs and
Atom, on newer CPUs (IceLake and later) TopDown can be collected
for any thread:
The top down metrics are collected per core instead of per CPU
thread. Per core mode is automatically enabled and -a (global
monitoring) is needed, requiring root rights or
perf.perf_event_paranoid=-1.
Topdown uses the full Performance Monitoring Unit, and needs
disabling of the NMI watchdog (as root): echo 0 >
/proc/sys/kernel/nmi_watchdog for best results. Otherwise the
bottlenecks may be inconsistent on workload with changing phases.
To interpret the results it is usually needed to know on which
CPUs the workload runs on. If needed the CPUs can be forced using
taskset.
--record-tpebs
Enable automatic sampling on Intel TPEBS retire_latency events
(event with :R modifier). Without this option, perf would not
capture dynamic retire_latency at runtime. Currently, a zero
value is assigned to the retire_latency event when this option
is not set. The TPEBS hardware feature starts from Intel
Granite Rapids microarchitecture. This option only exists in
X86_64 and is meaningful on Intel platforms with TPEBS
feature.
--tpebs-mode=[mean|min|max|last]
Set how retirement latency events have their sample times
combined. The default "mean" gives the average of retirement
latency. "min" or "max" give the smallest or largest retirment
latency times respectively. "last" uses the last retirment
latency sample’s time.
--td-level
Print the top-down statistics that equal the input level. It
allows users to print the interested top-down metrics level
instead of the level 1 top-down metrics.
As the higher levels gather more metrics and use more counters
they will be less accurate. By convention a metric can be examined
by appending _group to it and this will increase accuracy compared
to gathering all metrics for a level. For example, level 1
analysis may highlight tma_frontend_bound. This metric may be
drilled into with tma_frontend_bound_group with perf stat -M
tma_frontend_bound_group....
Error out if the input is higher than the supported max level.
--smi-cost
Measure SMI cost if msr/aperf/ and msr/smi/ events are
supported.
During the measurement, the /sys/device/cpu/freeze_on_smi will be
set to freeze core counters on SMI. The aperf counter will not be
effected by the setting. The cost of SMI can be measured by (aperf
- unhalted core cycles).
In practice, the percentages of SMI cycles is very useful for
performance oriented analysis. --metric_only will be applied by
default. The output is SMI cycles%, equals to (aperf - unhalted
core cycles) / aperf
Users who wants to get the actual value can apply
--no-metric-only.
--all-kernel
Configure all used events to run in kernel space.
--all-user
Configure all used events to run in user space.
--percore-show-thread
The event modifier "percore" has supported to sum up the event
counts for all hardware threads in a core and show the counts
per core.
This option with event modifier "percore" enabled also sums up the
event counts for all hardware threads in a core but show the sum
counts per hardware thread. This is essentially a replacement for
the any bit and convenient for post processing.
--summary
Print summary for interval mode (-I).
--no-csv-summary
Don’t print summary at the first column for CVS summary
output. This option must be used with -x and --summary.
This option can be enabled in perf config by setting the variable
stat.no-csv-summary.
$ perf config stat.no-csv-summary=true
--cputype
Only enable events on applying cpu with this type for hybrid
platform (e.g. core or atom)"
$ perf stat -- make
Performance counter stats for 'make':
83723.452481 task-clock:u (msec) # 1.004 CPUs utilized
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
3,228,188 page-faults:u # 0.039 M/sec
229,570,665,834 cycles:u # 2.742 GHz
313,163,853,778 instructions:u # 1.36 insn per cycle
69,704,684,856 branches:u # 832.559 M/sec
2,078,861,393 branch-misses:u # 2.98% of all branches
83.409183620 seconds time elapsed
74.684747000 seconds user
8.739217000 seconds sys
As displayed in the example above we can display 3 types of
timings. We always display the time the counters were
enabled/alive:
83.409183620 seconds time elapsed
For workload sessions we also display time the workloads spent in
user/system lands:
74.684747000 seconds user
8.739217000 seconds sys
Those times are the very same as displayed by the time tool.
With -x, perf stat is able to output a not-quite-CSV format output
Commas in the output are not put into "". To make it easy to parse
it is recommended to use a different character like -x \;
The fields are in this order:
• optional usec time stamp in fractions of second (with -I xxx)
• optional CPU, core, or socket identifier
• optional number of logical CPUs aggregated
• counter value
• unit of the counter value or empty
• event name
• run time of counter
• percentage of measurement time the counter was running
• optional variance if multiple values are collected with -r
• optional metric value
• optional unit of metric
Additional metrics may be printed with all earlier fields being
empty.
Support for Intel hybrid events within perf tools.
For some Intel platforms, such as AlderLake, which is hybrid
platform and it consists of atom cpu and core cpu. Each cpu has
dedicated event list. Part of events are available on core cpu,
part of events are available on atom cpu and even part of events
are available on both.
Kernel exports two new cpu pmus via sysfs:
/sys/bus/event_source/devices/cpu_core
/sys/bus/event_source/devices/cpu_atom
The cpus files are created under the directories. For example,
cat /sys/bus/event_source/devices/cpu_core/cpus 0-15
cat /sys/bus/event_source/devices/cpu_atom/cpus 16-23
It indicates cpu0-cpu15 are core cpus and cpu16-cpu23 are atom
cpus.
As before, use perf-list to list the symbolic event.
perf list
inst_retired.any [Fixed Counter: Counts the number of instructions
retired. Unit: cpu_atom] inst_retired.any [Number of instructions
retired. Fixed Counter - architectural event. Unit: cpu_core]
The Unit: xxx is added to brief description to indicate which pmu
the event is belong to. Same event name but with different pmu can
be supported.
Enable hybrid event with a specific pmu
To enable a core only event or atom only event, following syntax
is supported:
cpu_core/<event name>/
or
cpu_atom/<event name>/
For example, count the cycles event on core cpus.
perf stat -e cpu_core/cycles/
Create two events for one hardware event automatically
When creating one event and the event is available on both atom
and core, two events are created automatically. One is for atom,
the other is for core. Most of hardware events and cache events
are available on both cpu_core and cpu_atom.
For hardware events, they have pre-defined configs (e.g. 0 for
cycles). But on hybrid platform, kernel needs to know where the
event comes from (from atom or from core). The original perf event
type PERF_TYPE_HARDWARE can’t carry pmu information. So now this
type is extended to be PMU aware type. The PMU type ID is stored
at attr.config[63:32].
PMU type ID is retrieved from sysfs.
/sys/bus/event_source/devices/cpu_atom/type
/sys/bus/event_source/devices/cpu_core/type
The new attr.config layout for PERF_TYPE_HARDWARE:
PERF_TYPE_HARDWARE: 0xEEEEEEEE000000AA AA: hardware event ID
EEEEEEEE: PMU type ID
Cache event is similar. The type PERF_TYPE_HW_CACHE is extended to
be PMU aware type. The PMU type ID is stored at
attr.config[63:32].
The new attr.config layout for PERF_TYPE_HW_CACHE:
PERF_TYPE_HW_CACHE: 0xEEEEEEEE00DDCCBB BB: hardware cache ID CC:
hardware cache op ID DD: hardware cache op result ID EEEEEEEE: PMU
type ID
When enabling a hardware event without specified pmu, such as,
perf stat -e cycles -a (use system-wide in this example), two
events are created automatically.
------------------------------------------------------------
perf_event_attr:
size 120
config 0x400000000
sample_type IDENTIFIER
read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
disabled 1
inherit 1
exclude_guest 1
------------------------------------------------------------
and
------------------------------------------------------------
perf_event_attr:
size 120
config 0x800000000
sample_type IDENTIFIER
read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
disabled 1
inherit 1
exclude_guest 1
------------------------------------------------------------
type 0 is PERF_TYPE_HARDWARE. 0x4 in 0x400000000 indicates it’s
cpu_core pmu. 0x8 in 0x800000000 indicates it’s cpu_atom pmu (atom
pmu type id is random).
The kernel creates cycles (0x400000000) on cpu0-cpu15 (core cpus),
and create cycles (0x800000000) on cpu16-cpu23 (atom cpus).
For perf-stat result, it displays two events:
Performance counter stats for 'system wide':
6,744,979 cpu_core/cycles/
1,965,552 cpu_atom/cycles/
The first cycles is core event, the second cycles is atom event.
Thread mode example:
perf-stat reports the scaled counts for hybrid event and with a
percentage displayed. The percentage is the event’s running
time/enabling time.
One example, triad_loop runs on cpu16 (atom core), while we can
see the scaled value for core cycles is 160,444,092 and the
percentage is 0.47%.
perf stat -e cycles -- taskset -c 16 ./triad_loop
As previous, two events are created.
.ft C
perf_event_attr:
size 120
config 0x400000000
sample_type IDENTIFIER
read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
disabled 1
inherit 1
enable_on_exec 1
exclude_guest 1
.ft
and
.ft C
perf_event_attr:
size 120
config 0x800000000
sample_type IDENTIFIER
read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
disabled 1
inherit 1
enable_on_exec 1
exclude_guest 1
.ft
Performance counter stats for 'taskset -c 16 ./triad_loop':
233,066,666 cpu_core/cycles/ (0.43%)
604,097,080 cpu_atom/cycles/ (99.57%)
perf-record:
If there is no -e specified in perf record, on hybrid platform, it
creates two default cycles and adds them to event list. One is for
core, the other is for atom.
perf-stat:
If there is no -e specified in perf stat, on hybrid platform,
besides of software events, following events are created and added
to event list in order.
cpu_core/cycles/, cpu_atom/cycles/, cpu_core/instructions/,
cpu_atom/instructions/, cpu_core/branches/, cpu_atom/branches/,
cpu_core/branch-misses/, cpu_atom/branch-misses/
Of course, both perf-stat and perf-record support to enable hybrid
event with a specific pmu.
e.g. perf stat -e cpu_core/cycles/ perf stat -e cpu_atom/cycles/
perf stat -e cpu_core/r1a/ perf stat -e cpu_atom/L1-icache-loads/
perf stat -e cpu_core/cycles/,cpu_atom/instructions/ perf stat -e
{cpu_core/cycles/,cpu_core/instructions/}
But {cpu_core/cycles/,cpu_atom/instructions/} will return warning
and disable grouping, because the pmus in group are not matched
(cpu_core vs. cpu_atom).
With -j, perf stat is able to print out a JSON format output that
can be used for parsing.
• interval : optional timestamp in fractions of second (with -I)
• optional aggregate options:
• core : core identifier (with --per-core)
• die : die identifier (with --per-die)
• socket : socket identifier (with --per-socket)
• node : node identifier (with --per-node)
• thread : thread identifier (with --per-thread)
• counters : number of aggregated PMU counters
• counter-value : counter value
• unit : unit of the counter value or empty
• event : event name
• variance : optional variance if multiple values are collected
(with -r)
• event-runtime : run time of the event
• pcnt-running : percentage of time the event was running
• metric-value : optional metric value
• metric-unit : optional unit of metric
perf-top(1), perf-list(1)
This page is part of the perf (Performance analysis tools for
Linux (in Linux source tree)) project. Information about the
project can be found at
⟨https://perf.wiki.kernel.org/index.php/Main_Page⟩. If you have a
bug report for this manual page, send it to
[email protected]. This page was obtained from the
project's upstream Git repository
⟨http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git⟩
on 2025-08-11. (At that time, the date of the most recent commit
that was found in the repository was 2025-08-10.) If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a
mail to [email protected]
perf 2025-06-27 PERF-STAT(1)
Pages that refer to this page: perf(1), perf-iostat(1), perf-kvm(1), perf-list(1), perf-record(1), perf-report(1), perf-top(1)
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