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54b5091606
Add a new mode to only print metrics. Sometimes we don't care about the
raw values, just want the computed metrics. This allows more compact
printing, so with -I each sample is only a single line. This also
allows easier plotting and processing with other tools.
The main target is with using --topdown, but it also works with -T and
standard perf stat. A few metrics are not supported.
To avoiding having to hardcode all the metrics in the code it uses a two
pass approach: first compute dummy metrics and only print the headers in
the print_metric callback. Then use the callback to print the actual
values.
There are some additional changes in the stat printout code to handle
all metrics being on a single line.
One issue is that the column code doesn't know in advance what events
are not supported by the CPU, and it would be hard to find out as this
could change based on dynamic conditions. That causes empty columns in
some cases.
The output can be fairly wide, often you may need more than 80 columns.
Example:
% perf stat -a -I 1000 --metric-only
1.001452803 frontend cycles idle insn per cycle stalled cycles per insn branch-misses of all branches
1.001452803 158.91% 0.66 2.39 2.92%
2.002192321 180.63% 0.76 2.08 2.96%
3.003088282 150.59% 0.62 2.57 2.84%
4.004369835 196.20% 0.98 1.62 3.79%
5.005227314 231.98% 0.84 1.90 4.71%
v2: Lots of updates.
v3: Use slightly narrower columns
v4: Add comment
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/1457049458-28956-6-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
252 lines
7.3 KiB
Plaintext
252 lines
7.3 KiB
Plaintext
perf-stat(1)
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============
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NAME
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----
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perf-stat - Run a command and gather performance counter statistics
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SYNOPSIS
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--------
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[verse]
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'perf stat' [-e <EVENT> | --event=EVENT] [-a] <command>
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'perf stat' [-e <EVENT> | --event=EVENT] [-a] -- <command> [<options>]
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'perf stat' [-e <EVENT> | --event=EVENT] [-a] record [-o file] -- <command> [<options>]
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'perf stat' report [-i file]
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DESCRIPTION
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-----------
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This command runs a command and gathers performance counter statistics
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from it.
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OPTIONS
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-------
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<command>...::
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Any command you can specify in a shell.
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record::
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See STAT RECORD.
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report::
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See STAT REPORT.
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-e::
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--event=::
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Select the PMU event. Selection can be:
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- a symbolic event name (use 'perf list' to list all events)
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- a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a
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hexadecimal event descriptor.
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- a symbolically formed event like 'pmu/param1=0x3,param2/' where
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param1 and param2 are defined as formats for the PMU in
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/sys/bus/event_sources/devices/<pmu>/format/*
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- a symbolically formed event like 'pmu/config=M,config1=N,config2=K/'
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where M, N, K are numbers (in decimal, hex, octal format).
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Acceptable values for each of 'config', 'config1' and 'config2'
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parameters are defined by corresponding entries in
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/sys/bus/event_sources/devices/<pmu>/format/*
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-i::
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--no-inherit::
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child tasks do not inherit counters
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-p::
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--pid=<pid>::
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stat events on existing process id (comma separated list)
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-t::
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--tid=<tid>::
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stat events on existing thread id (comma separated list)
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-a::
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--all-cpus::
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system-wide collection from all CPUs
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-c::
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--scale::
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scale/normalize counter values
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-d::
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--detailed::
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print more detailed statistics, can be specified up to 3 times
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-d: detailed events, L1 and LLC data cache
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-d -d: more detailed events, dTLB and iTLB events
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-d -d -d: very detailed events, adding prefetch events
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-r::
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--repeat=<n>::
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repeat command and print average + stddev (max: 100). 0 means forever.
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-B::
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--big-num::
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print large numbers with thousands' separators according to locale
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-C::
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--cpu=::
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Count only on the list of CPUs provided. Multiple CPUs can be provided as a
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comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
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In per-thread mode, this option is ignored. The -a option is still necessary
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to activate system-wide monitoring. Default is to count on all CPUs.
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-A::
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--no-aggr::
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Do not aggregate counts across all monitored CPUs in system-wide mode (-a).
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This option is only valid in system-wide mode.
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-n::
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--null::
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null run - don't start any counters
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-v::
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--verbose::
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be more verbose (show counter open errors, etc)
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-x SEP::
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--field-separator SEP::
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print counts using a CSV-style output to make it easy to import directly into
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spreadsheets. Columns are separated by the string specified in SEP.
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-G name::
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--cgroup name::
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monitor only in the container (cgroup) called "name". This option is available only
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in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to
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container "name" are monitored when they run on the monitored CPUs. Multiple cgroups
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can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup
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to first event, second cgroup to second event and so on. It is possible to provide
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an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have
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corresponding events, i.e., they always refer to events defined earlier on the command
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line.
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-o file::
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--output file::
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Print the output into the designated file.
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--append::
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Append to the output file designated with the -o option. Ignored if -o is not specified.
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--log-fd::
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Log output to fd, instead of stderr. Complementary to --output, and mutually exclusive
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with it. --append may be used here. Examples:
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3>results perf stat --log-fd 3 -- $cmd
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3>>results perf stat --log-fd 3 --append -- $cmd
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--pre::
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--post::
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Pre and post measurement hooks, e.g.:
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perf stat --repeat 10 --null --sync --pre 'make -s O=defconfig-build/clean' -- make -s -j64 O=defconfig-build/ bzImage
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-I msecs::
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--interval-print msecs::
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Print count deltas every N milliseconds (minimum: 10ms)
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The overhead percentage could be high in some cases, for instance with small, sub 100ms intervals. Use with caution.
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example: 'perf stat -I 1000 -e cycles -a sleep 5'
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--metric-only::
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Only print computed metrics. Print them in a single line.
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Don't show any raw values. Not supported with -A or --per-thread.
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--per-socket::
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Aggregate counts per processor socket for system-wide mode measurements. This
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is a useful mode to detect imbalance between sockets. To enable this mode,
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use --per-socket in addition to -a. (system-wide). The output includes the
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socket number and the number of online processors on that socket. This is
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useful to gauge the amount of aggregation.
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--per-core::
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Aggregate counts per physical processor for system-wide mode measurements. This
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is a useful mode to detect imbalance between physical cores. To enable this mode,
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use --per-core in addition to -a. (system-wide). The output includes the
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core number and the number of online logical processors on that physical processor.
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--per-thread::
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Aggregate counts per monitored threads, when monitoring threads (-t option)
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or processes (-p option).
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-D msecs::
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--delay msecs::
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After starting the program, wait msecs before measuring. This is useful to
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filter out the startup phase of the program, which is often very different.
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-T::
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--transaction::
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Print statistics of transactional execution if supported.
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STAT RECORD
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-----------
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Stores stat data into perf data file.
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-o file::
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--output file::
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Output file name.
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STAT REPORT
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-----------
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Reads and reports stat data from perf data file.
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-i file::
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--input file::
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Input file name.
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--per-socket::
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Aggregate counts per processor socket for system-wide mode measurements.
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--per-core::
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Aggregate counts per physical processor for system-wide mode measurements.
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-A::
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--no-aggr::
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Do not aggregate counts across all monitored CPUs.
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EXAMPLES
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--------
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$ perf stat -- make -j
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Performance counter stats for 'make -j':
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8117.370256 task clock ticks # 11.281 CPU utilization factor
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678 context switches # 0.000 M/sec
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133 CPU migrations # 0.000 M/sec
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235724 pagefaults # 0.029 M/sec
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24821162526 CPU cycles # 3057.784 M/sec
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18687303457 instructions # 2302.138 M/sec
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172158895 cache references # 21.209 M/sec
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27075259 cache misses # 3.335 M/sec
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Wall-clock time elapsed: 719.554352 msecs
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CSV FORMAT
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----------
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With -x, perf stat is able to output a not-quite-CSV format output
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Commas in the output are not put into "". To make it easy to parse
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it is recommended to use a different character like -x \;
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The fields are in this order:
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- optional usec time stamp in fractions of second (with -I xxx)
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- optional CPU, core, or socket identifier
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- optional number of logical CPUs aggregated
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- counter value
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- unit of the counter value or empty
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- event name
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- run time of counter
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- percentage of measurement time the counter was running
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- optional variance if multiple values are collected with -r
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- optional metric value
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- optional unit of metric
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Additional metrics may be printed with all earlier fields being empty.
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SEE ALSO
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--------
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linkperf:perf-top[1], linkperf:perf-list[1]
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