tools/perf/Documentation/perf-trace.txt

   1 perf-trace(1)
   2 =============
   3
   4 NAME
   5 ----
   6 perf-trace - strace inspired tool
   7
   8 SYNOPSIS
   9 --------
  10 [verse]
  11 'perf trace'
  12 'perf trace record'
  13
  14 DESCRIPTION
  15 -----------
  16 This command will show the events associated with the target, initially
  17 syscalls, but other system events like pagefaults, task lifetime events,
  18 scheduling events, etc.
  19
  20 This is a live mode tool in addition to working with perf.data files like
  21 the other perf tools. Files can be generated using the 'perf record' command
  22 but the session needs to include the raw_syscalls events (-e 'raw_syscalls:*').
  23 Alternatively, 'perf trace record' can be used as a shortcut to
  24 automatically include the raw_syscalls events when writing events to a file.
  25
  26 The following options apply to perf trace; options to perf trace record are
  27 found in the perf record man page.
  28
  29 OPTIONS
  30 -------
  31
  32 -a::
  33 --all-cpus::
  34         System-wide collection from all CPUs.
  35
  36 -e::
  37 --expr::
  38         List of syscalls to show, currently only syscall names.
  39         Prefixing with ! shows all syscalls but the ones specified.  You may
  40         need to escape it.
  41
  42 -o::
  43 --output=::
  44         Output file name.
  45
  46 -p::
  47 --pid=::
  48         Record events on existing process ID (comma separated list).
  49
  50 -t::
  51 --tid=::
  52         Record events on existing thread ID (comma separated list).
  53
  54 -u::
  55 --uid=::
  56         Record events in threads owned by uid. Name or number.
  57
  58 --filter-pids=::
  59         Filter out events for these pids and for 'trace' itself (comma separated list).
  60
  61 -v::
  62 --verbose=::
  63         Verbosity level.
  64
  65 --no-inherit::
  66         Child tasks do not inherit counters.
  67
  68 -m::
  69 --mmap-pages=::
  70         Number of mmap data pages (must be a power of two) or size
  71         specification with appended unit character - B/K/M/G. The
  72         size is rounded up to have nearest pages power of two value.
  73
  74 -C::
  75 --cpu::
  76 Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a
  77 comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.
  78 In per-thread mode with inheritance mode on (default), Events are captured only when
  79 the thread executes on the designated CPUs. Default is to monitor all CPUs.
  80
  81 --duration:
  82         Show only events that had a duration greater than N.M ms.
  83
  84 --sched:
  85         Accrue thread runtime and provide a summary at the end of the session.
  86
  87 -i
  88 --input
  89         Process events from a given perf data file.
  90
  91 -T
  92 --time
  93         Print full timestamp rather time relative to first sample.
  94
  95 --comm::
  96         Show process COMM right beside its ID, on by default, disable with --no-comm.
  97
  98 -s::
  99 --summary::
 100         Show only a summary of syscalls by thread with min, max, and average times
 101     (in msec) and relative stddev.
 102
 103 -S::
 104 --with-summary::
 105         Show all syscalls followed by a summary by thread with min, max, and
 106     average times (in msec) and relative stddev.
 107
 108 --tool_stats::
 109         Show tool stats such as number of times fd->pathname was discovered thru
 110         hooking the open syscall return + vfs_getname or via reading /proc/pid/fd, etc.
 111
 112 -F=[all|min|maj]::
 113 --pf=[all|min|maj]::
 114         Trace pagefaults. Optionally, you can specify whether you want minor,
 115         major or all pagefaults. Default value is maj.
 116
 117 --syscalls::
 118         Trace system calls. This options is enabled by default.
 119
 120 --call-graph [mode,type,min[,limit],order[,key][,branch]]::
 121         Setup and enable call-graph (stack chain/backtrace) recording.
 122         See `--call-graph` section in perf-record and perf-report
 123         man pages for details. The ones that are most useful in 'perf trace'
 124         are 'dwarf' and 'lbr', where available, try: 'perf trace --call-graph dwarf'.
 125
 126         Using this will, for the root user, bump the value of --mmap-pages to 4
 127         times the maximum for non-root users, based on the kernel.perf_event_mlock_kb
 128         sysctl. This is done only if the user doesn't specify a --mmap-pages value.
 129
 130 --kernel-syscall-graph::
 131          Show the kernel callchains on the syscall exit path.
 132
 133 --event::
 134         Trace other events, see 'perf list' for a complete list.
 135
 136 --max-stack::
 137         Set the stack depth limit when parsing the callchain, anything
 138         beyond the specified depth will be ignored. Note that at this point
 139         this is just about the presentation part, i.e. the kernel is still
 140         not limiting, the overhead of callchains needs to be set via the
 141         knobs in --call-graph dwarf.
 142
 143         Implies '--call-graph dwarf' when --call-graph not present on the
 144         command line, on systems where DWARF unwinding was built in.
 145
 146         Default: /proc/sys/kernel/perf_event_max_stack when present for
 147                  live sessions (without --input/-i), 127 otherwise.
 148
 149 --min-stack::
 150         Set the stack depth limit when parsing the callchain, anything
 151         below the specified depth will be ignored. Disabled by default.
 152
 153         Implies '--call-graph dwarf' when --call-graph not present on the
 154         command line, on systems where DWARF unwinding was built in.
 155
 156 --proc-map-timeout::
 157         When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
 158         because the file may be huge. A time out is needed in such cases.
 159         This option sets the time out limit. The default value is 500 ms.
 160
 161 PAGEFAULTS
 162 ----------
 163
 164 When tracing pagefaults, the format of the trace is as follows:
 165
 166 <min|maj>fault [<ip.symbol>+<ip.offset>] => <addr.dso@addr.offset> (<map type><addr level>).
 167
 168 - min/maj indicates whether fault event is minor or major;
 169 - ip.symbol shows symbol for instruction pointer (the code that generated the
 170   fault); if no debug symbols available, perf trace will print raw IP;
 171 - addr.dso shows DSO for the faulted address;
 172 - map type is either 'd' for non-executable maps or 'x' for executable maps;
 173 - addr level is either 'k' for kernel dso or '.' for user dso.
 174
 175 For symbols resolution you may need to install debugging symbols.
 176
 177 Please be aware that duration is currently always 0 and doesn't reflect actual
 178 time it took for fault to be handled!
 179
 180 When --verbose specified, perf trace tries to print all available information
 181 for both IP and fault address in the form of dso@symbol+offset.
 182
 183 EXAMPLES
 184 --------
 185
 186 Trace only major pagefaults:
 187
 188  $ perf trace --no-syscalls -F
 189
 190 Trace syscalls, major and minor pagefaults:
 191
 192  $ perf trace -F all
 193
 194   1416.547 ( 0.000 ms): python/20235 majfault [CRYPTO_push_info_+0x0] => /lib/x86_64-linux-gnu/libcrypto.so.1.0.0@0x61be0 (x.)
 195
 196   As you can see, there was major pagefault in python process, from
 197   CRYPTO_push_info_ routine which faulted somewhere in libcrypto.so.
 198
 199 SEE ALSO
 200 --------
 201 linkperf:perf-record[1], linkperf:perf-script[1]