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PERF-TOP(1) perf Manual PERF-TOP(1)

NAME

perf-top - System profiling tool.

SYNOPSIS

perf top [-e <EVENT> | --event=EVENT] [<options>]

DESCRIPTION

This command generates and displays a performance counter profile in real time.

OPTIONS

-a, --all-cpus

System-wide collection. (default)

-c <count>, --count=<count>

Event period to sample.

-C <cpu-list>, --cpu=<cpu>

Monitor 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. Default is to monitor all CPUS.

-d <seconds>, --delay=<seconds>

Number of seconds to delay between refreshes.

-e <event>, --event=<event>

Select the PMU event. Selection can be a symbolic event name (use perf list to list all events) or a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a hexadecimal event descriptor.

-E <entries>, --entries=<entries>

Display this many functions.

-f <count>, --count-filter=<count>

Only display functions with more events than this.

--group

Put the counters into a counter group.

-F <freq>, --freq=<freq>

Profile at this frequency.

-i, --inherit

Child tasks do not inherit counters.

-k <path>, --vmlinux=<path>

Path to vmlinux. Required for annotation functionality.

-m <pages>, --mmap-pages=<pages>

Number of mmap data pages (must be a power of two) or size specification with appended unit character - B/K/M/G. The size is rounded up to have nearest pages power of two value.

-p <pid>, --pid=<pid>

Profile events on existing Process ID (comma separated list).

-t <tid>, --tid=<tid>

Profile events on existing thread ID (comma separated list).

-u, --uid=

Record events in threads owned by uid. Name or number.

-r <priority>, --realtime=<priority>

Collect data with this RT SCHED_FIFO priority.

--sym-annotate=<symbol>

Annotate this symbol.

-K, --hide_kernel_symbols

Hide kernel symbols.

-U, --hide_user_symbols

Hide user symbols.

--demangle-kernel

Demangle kernel symbols.

-D, --dump-symtab

Dump the symbol table used for profiling.

-v, --verbose

Be more verbose (show counter open errors, etc).

-z, --zero

Zero history across display updates.

-s, --sort

Sort by key(s): pid, comm, dso, symbol, parent, srcline, weight, local_weight, abort, in_tx, transaction, overhead, sample, period. Please see description of --sort in the perf-report man page.

--fields=

Specify output field - multiple keys can be specified in CSV format. Following fields are available: overhead, overhead_sys, overhead_us, overhead_children, sample and period. Also it can contain any sort key(s). 

By default, every sort keys not specified in --field will be appended
automatically.

-n, --show-nr-samples

Show a column with the number of samples.

--show-total-period

Show a column with the sum of periods.

--dsos

Only consider symbols in these dsos. This option will affect the percentage of the overhead column. See --percentage for more info.

--comms

Only consider symbols in these comms. This option will affect the percentage of the overhead column. See --percentage for more info.

--symbols

Only consider these symbols. This option will affect the percentage of the overhead column. See --percentage for more info.

-M, --disassembler-style=

Set disassembler style for objdump.

--source

Interleave source code with assembly code. Enabled by default, disable with --no-source.

--asm-raw

Show raw instruction encoding of assembly instructions.

-g

Enables call-graph (stack chain/backtrace) recording.

--call-graph

Setup and enable call-graph (stack chain/backtrace) recording, implies -g.

--children

Accumulate callchain of children to parent entry so that then can show up in the output. The output will have a new "Children" column and will be sorted on the data. It requires -g/--call-graph option enabled.

--max-stack

Set the stack depth limit when parsing the callchain, anything beyond the specified depth will be ignored. This is a trade-off between information loss and faster processing especially for workloads that can have a very long callchain stack. 

Default: 127

--ignore-callees=<regex>

Ignore callees of the function(s) matching the given regex. This has the effect of collecting the callers of each such function into one place in the call-graph tree.

--percent-limit

Do not show entries which have an overhead under that percent. (Default: 0).

--percentage

Determine how to display the overhead percentage of filtered entries. Filters can be applied by --comms, --dsos and/or --symbols options and Zoom operations on the TUI (thread, dso, etc). 

"relative" means it´s relative to filtered entries only so that the
sum of shown entries will be always 100%. "absolute" means it retains
the original value before and after the filter is applied.

-w, --column-widths=<width[,width...]>

Force each column width to the provided list, for large terminal readability. 0 means no limit (default behavior).

-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. For a full list of modifiers please see the perf record manpage. 

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.

INTERACTIVE PROMPTING KEYS

[d]

Display refresh delay.

[e]

Number of entries to display.

[E]

Event to display when multiple counters are active.

[f]

Profile display filter (>= hit count).

[F]

Annotation display filter (>= % of total).

[s]

Annotate symbol.

[S]

Stop annotation, return to full profile display.

[z]

Toggle event count zeroing across display updates.

[qQ]

Quit.

Pressing any unmapped key displays a menu, and prompts for input.

SEE ALSO

perf-stat(1), perf-list(1), perf-report(1)

05/02/2024 perf