202 lines
6.3 KiB
Plaintext
202 lines
6.3 KiB
Plaintext
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perf-trace(1)
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=============
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NAME
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----
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perf-trace - strace inspired tool
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SYNOPSIS
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--------
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[verse]
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'perf trace'
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'perf trace record'
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DESCRIPTION
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-----------
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This command will show the events associated with the target, initially
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syscalls, but other system events like pagefaults, task lifetime events,
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scheduling events, etc.
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This is a live mode tool in addition to working with perf.data files like
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the other perf tools. Files can be generated using the 'perf record' command
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but the session needs to include the raw_syscalls events (-e 'raw_syscalls:*').
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Alternatively, 'perf trace record' can be used as a shortcut to
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automatically include the raw_syscalls events when writing events to a file.
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The following options apply to perf trace; options to perf trace record are
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found in the perf record man page.
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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 from all CPUs.
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-e::
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--expr::
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List of syscalls to show, currently only syscall names.
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Prefixing with ! shows all syscalls but the ones specified. You may
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need to escape it.
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-o::
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--output=::
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Output file name.
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-p::
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--pid=::
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Record events on existing process ID (comma separated list).
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-t::
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--tid=::
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Record 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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--filter-pids=::
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Filter out events for these pids and for 'trace' itself (comma separated list).
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-v::
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--verbose=::
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Verbosity level.
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--no-inherit::
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Child tasks do not inherit counters.
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-m::
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--mmap-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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-C::
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--cpu::
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Collect samples 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 with inheritance mode on (default), Events are captured only when
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the thread executes on the designated CPUs. Default is to monitor all CPUs.
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--duration:
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Show only events that had a duration greater than N.M ms.
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--sched:
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Accrue thread runtime and provide a summary at the end of the session.
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-i
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--input
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Process events from a given perf data file.
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-T
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--time
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Print full timestamp rather time relative to first sample.
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--comm::
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Show process COMM right beside its ID, on by default, disable with --no-comm.
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-s::
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--summary::
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Show only a summary of syscalls by thread with min, max, and average times
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(in msec) and relative stddev.
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-S::
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--with-summary::
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Show all syscalls followed by a summary by thread with min, max, and
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average times (in msec) and relative stddev.
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--tool_stats::
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Show tool stats such as number of times fd->pathname was discovered thru
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hooking the open syscall return + vfs_getname or via reading /proc/pid/fd, etc.
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-F=[all|min|maj]::
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--pf=[all|min|maj]::
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Trace pagefaults. Optionally, you can specify whether you want minor,
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major or all pagefaults. Default value is maj.
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--syscalls::
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Trace system calls. This options is enabled by default.
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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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See `--call-graph` section in perf-record and perf-report
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man pages for details. The ones that are most useful in 'perf trace'
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are 'dwarf' and 'lbr', where available, try: 'perf trace --call-graph dwarf'.
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Using this will, for the root user, bump the value of --mmap-pages to 4
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times the maximum for non-root users, based on the kernel.perf_event_mlock_kb
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sysctl. This is done only if the user doesn't specify a --mmap-pages value.
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--kernel-syscall-graph::
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Show the kernel callchains on the syscall exit path.
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--event::
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Trace other events, see 'perf list' for a complete list.
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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. Note that at this point
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this is just about the presentation part, i.e. the kernel is still
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not limiting, the overhead of callchains needs to be set via the
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knobs in --call-graph dwarf.
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Implies '--call-graph dwarf' when --call-graph not present on the
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command line, on systems where DWARF unwinding was built in.
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Default: /proc/sys/kernel/perf_event_max_stack when present for
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live sessions (without --input/-i), 127 otherwise.
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--min-stack::
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Set the stack depth limit when parsing the callchain, anything
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below the specified depth will be ignored. Disabled by default.
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Implies '--call-graph dwarf' when --call-graph not present on the
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command line, on systems where DWARF unwinding was built in.
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--proc-map-timeout::
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When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
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because the file may be huge. A time out is needed in such cases.
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This option sets the time out limit. The default value is 500 ms.
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PAGEFAULTS
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----------
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When tracing pagefaults, the format of the trace is as follows:
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<min|maj>fault [<ip.symbol>+<ip.offset>] => <addr.dso@addr.offset> (<map type><addr level>).
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- min/maj indicates whether fault event is minor or major;
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- ip.symbol shows symbol for instruction pointer (the code that generated the
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fault); if no debug symbols available, perf trace will print raw IP;
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- addr.dso shows DSO for the faulted address;
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- map type is either 'd' for non-executable maps or 'x' for executable maps;
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- addr level is either 'k' for kernel dso or '.' for user dso.
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For symbols resolution you may need to install debugging symbols.
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Please be aware that duration is currently always 0 and doesn't reflect actual
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time it took for fault to be handled!
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When --verbose specified, perf trace tries to print all available information
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for both IP and fault address in the form of dso@symbol+offset.
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EXAMPLES
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--------
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Trace only major pagefaults:
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$ perf trace --no-syscalls -F
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Trace syscalls, major and minor pagefaults:
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$ perf trace -F all
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1416.547 ( 0.000 ms): python/20235 majfault [CRYPTO_push_info_+0x0] => /lib/x86_64-linux-gnu/libcrypto.so.1.0.0@0x61be0 (x.)
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As you can see, there was major pagefault in python process, from
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CRYPTO_push_info_ routine which faulted somewhere in libcrypto.so.
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SEE ALSO
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--------
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linkperf:perf-record[1], linkperf:perf-script[1]
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