351 строка
10 KiB
Plaintext
351 строка
10 KiB
Plaintext
perf-top(1)
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===========
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NAME
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----
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perf-top - System profiling tool.
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SYNOPSIS
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--------
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[verse]
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'perf top' [-e <EVENT> | --event=EVENT] [<options>]
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DESCRIPTION
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-----------
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This command generates and displays a performance counter profile in real time.
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OPTIONS
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-------
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-a::
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--all-cpus::
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System-wide collection. (default)
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-c <count>::
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--count=<count>::
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Event period to sample.
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-C <cpu-list>::
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--cpu=<cpu>::
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Monitor 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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Default is to monitor all CPUS.
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-d <seconds>::
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--delay=<seconds>::
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Number of seconds to delay between refreshes.
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-e <event>::
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--event=<event>::
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Select the PMU event. Selection can be a symbolic event name
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(use 'perf list' to list all events) or a raw PMU
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event (eventsel+umask) in the form of rNNN where NNN is a
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hexadecimal event descriptor.
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-E <entries>::
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--entries=<entries>::
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Display this many functions.
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-f <count>::
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--count-filter=<count>::
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Only display functions with more events than this.
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--group::
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Put the counters into a counter group.
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-F <freq>::
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--freq=<freq>::
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Profile at this frequency. Use 'max' to use the currently maximum
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allowed frequency, i.e. the value in the kernel.perf_event_max_sample_rate
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sysctl.
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-i::
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--inherit::
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Child tasks do not inherit counters.
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-k <path>::
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--vmlinux=<path>::
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Path to vmlinux. Required for annotation functionality.
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--ignore-vmlinux::
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Ignore vmlinux files.
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--kallsyms=<file>::
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kallsyms pathname
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-m <pages>::
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--mmap-pages=<pages>::
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Number of mmap data pages (must be a power of two) or size
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specification with appended unit character - B/K/M/G. The
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size is rounded up to have nearest pages power of two value.
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-p <pid>::
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--pid=<pid>::
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Profile events on existing Process ID (comma separated list).
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-t <tid>::
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--tid=<tid>::
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Profile events on existing thread ID (comma separated list).
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-u::
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--uid=::
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Record events in threads owned by uid. Name or number.
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-r <priority>::
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--realtime=<priority>::
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Collect data with this RT SCHED_FIFO priority.
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--sym-annotate=<symbol>::
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Annotate this symbol.
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-K::
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--hide_kernel_symbols::
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Hide kernel symbols.
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-U::
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--hide_user_symbols::
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Hide user symbols.
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--demangle-kernel::
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Demangle kernel symbols.
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-D::
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--dump-symtab::
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Dump the symbol table used for profiling.
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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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-z::
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--zero::
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Zero history across display updates.
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-s::
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--sort::
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Sort by key(s): pid, comm, dso, symbol, parent, srcline, weight,
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local_weight, abort, in_tx, transaction, overhead, sample, period.
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Please see description of --sort in the perf-report man page.
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--fields=::
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Specify output field - multiple keys can be specified in CSV format.
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Following fields are available:
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overhead, overhead_sys, overhead_us, overhead_children, sample and period.
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Also it can contain any sort key(s).
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By default, every sort keys not specified in --field will be appended
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automatically.
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-n::
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--show-nr-samples::
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Show a column with the number of samples.
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--show-total-period::
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Show a column with the sum of periods.
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--dsos::
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Only consider symbols in these dsos. This option will affect the
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percentage of the overhead column. See --percentage for more info.
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--comms::
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Only consider symbols in these comms. This option will affect the
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percentage of the overhead column. See --percentage for more info.
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--symbols::
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Only consider these symbols. This option will affect the
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percentage of the overhead column. See --percentage for more info.
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-M::
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--disassembler-style=:: Set disassembler style for objdump.
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--source::
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Interleave source code with assembly code. Enabled by default,
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disable with --no-source.
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--asm-raw::
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Show raw instruction encoding of assembly instructions.
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-g::
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Enables call-graph (stack chain/backtrace) recording.
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--call-graph [mode,type,min[,limit],order[,key][,branch]]::
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Setup and enable call-graph (stack chain/backtrace) recording,
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implies -g. See `--call-graph` section in perf-record and
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perf-report man pages for details.
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--children::
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Accumulate callchain of children to parent entry so that then can
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show up in the output. The output will have a new "Children" column
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and will be sorted on the data. It requires -g/--call-graph option
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enabled. See the `overhead calculation' section for more details.
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Enabled by default, disable with --no-children.
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--max-stack::
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Set the stack depth limit when parsing the callchain, anything
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beyond the specified depth will be ignored. This is a trade-off
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between information loss and faster processing especially for
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workloads that can have a very long callchain stack.
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Default: /proc/sys/kernel/perf_event_max_stack when present, 127 otherwise.
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--ignore-callees=<regex>::
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Ignore callees of the function(s) matching the given regex.
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This has the effect of collecting the callers of each such
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function into one place in the call-graph tree.
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--percent-limit::
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Do not show entries which have an overhead under that percent.
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(Default: 0).
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--percentage::
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Determine how to display the overhead percentage of filtered entries.
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Filters can be applied by --comms, --dsos and/or --symbols options and
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Zoom operations on the TUI (thread, dso, etc).
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"relative" means it's relative to filtered entries only so that the
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sum of shown entries will be always 100%. "absolute" means it retains
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the original value before and after the filter is applied.
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-w::
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--column-widths=<width[,width...]>::
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Force each column width to the provided list, for large terminal
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readability. 0 means no limit (default behavior).
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--proc-map-timeout::
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When processing pre-existing threads /proc/XXX/mmap, it may take
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a long time, because the file may be huge. A time out is needed
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in such cases.
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This option sets the time out limit. The default value is 500 ms.
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-b::
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--branch-any::
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Enable taken branch stack sampling. Any type of taken branch may be sampled.
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This is a shortcut for --branch-filter any. See --branch-filter for more infos.
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-j::
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--branch-filter::
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Enable taken branch stack sampling. Each sample captures a series of consecutive
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taken branches. The number of branches captured with each sample depends on the
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underlying hardware, the type of branches of interest, and the executed code.
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It is possible to select the types of branches captured by enabling filters.
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For a full list of modifiers please see the perf record manpage.
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The option requires at least one branch type among any, any_call, any_ret, ind_call, cond.
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The privilege levels may be omitted, in which case, the privilege levels of the associated
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event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege
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levels are subject to permissions. When sampling on multiple events, branch stack sampling
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is enabled for all the sampling events. The sampled branch type is the same for all events.
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The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k
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Note that this feature may not be available on all processors.
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--raw-trace::
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When displaying traceevent output, do not use print fmt or plugins.
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--hierarchy::
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Enable hierarchy output.
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--overwrite::
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Enable this to use just the most recent records, which helps in high core count
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machines such as Knights Landing/Mill, but right now is disabled by default as
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the pausing used in this technique is leading to loss of metadata events such
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as PERF_RECORD_MMAP which makes 'perf top' unable to resolve samples, leading
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to lots of unknown samples appearing on the UI. Enable this if you are in such
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machines and profiling a workload that doesn't creates short lived threads and/or
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doesn't uses many executable mmap operations. Work is being planed to solve
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this situation, till then, this will remain disabled by default.
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--force::
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Don't do ownership validation.
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--num-thread-synthesize::
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The number of threads to run when synthesizing events for existing processes.
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By default, the number of threads equals to the number of online CPUs.
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--namespaces::
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Record events of type PERF_RECORD_NAMESPACES and display it with the
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'cgroup_id' sort key.
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--switch-on EVENT_NAME::
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Only consider events after this event is found.
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E.g.:
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Find out where broadcast packets are handled
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perf probe -L icmp_rcv
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Insert a probe there:
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perf probe icmp_rcv:59
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Start perf top and ask it to only consider the cycles events when a
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broadcast packet arrives This will show a menu with two entries and
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will start counting when a broadcast packet arrives:
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perf top -e cycles,probe:icmp_rcv --switch-on=probe:icmp_rcv
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Alternatively one can ask for --group and then two overhead columns
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will appear, the first for cycles and the second for the switch-on event.
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perf top --group -e cycles,probe:icmp_rcv --switch-on=probe:icmp_rcv
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This may be interesting to measure a workload only after some initialization
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phase is over, i.e. insert a perf probe at that point and use the above
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examples replacing probe:icmp_rcv with the just-after-init probe.
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--switch-off EVENT_NAME::
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Stop considering events after this event is found.
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--show-on-off-events::
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Show the --switch-on/off events too. This has no effect in 'perf top' now
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but probably we'll make the default not to show the switch-on/off events
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on the --group mode and if there is only one event besides the off/on ones,
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go straight to the histogram browser, just like 'perf top' with no events
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explicitely specified does.
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INTERACTIVE PROMPTING KEYS
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--------------------------
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[d]::
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Display refresh delay.
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[e]::
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Number of entries to display.
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[E]::
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Event to display when multiple counters are active.
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[f]::
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Profile display filter (>= hit count).
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[F]::
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Annotation display filter (>= % of total).
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[s]::
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Annotate symbol.
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[S]::
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Stop annotation, return to full profile display.
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[K]::
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Hide kernel symbols.
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[U]::
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Hide user symbols.
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[z]::
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Toggle event count zeroing across display updates.
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[qQ]::
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Quit.
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Pressing any unmapped key displays a menu, and prompts for input.
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include::callchain-overhead-calculation.txt[]
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SEE ALSO
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--------
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linkperf:perf-stat[1], linkperf:perf-list[1], linkperf:perf-report[1]
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