NAME

       perf-trace - strace inspired tool

SYNOPSIS

       perf trace
       perf trace record

DESCRIPTION

       This command will show the events associated with the target, initially syscalls, but
       other system events like pagefaults, task lifetime events, scheduling events, etc.

       This is a live mode tool in addition to working with perf.data files like the other perf
       tools. Files can be generated using the perf record command but the session needs to
       include the raw_syscalls events (-e raw_syscalls:*). Alternatively, perf trace record can
       be used as a shortcut to automatically include the raw_syscalls events when writing events
       to a file.

       The following options apply to perf trace; options to perf trace record are found in the
       perf record man page.

OPTIONS

       -a, --all-cpus
           System-wide collection from all CPUs.

       -e, --expr
           List of syscalls to show, currently only syscall names. Prefixing with ! shows all
           syscalls but the ones specified. You may need to escape it.

       -o, --output=
           Output file name.

       -p, --pid=
           Record events on existing process ID (comma separated list).

       -t, --tid=
           Record events on existing thread ID (comma separated list).

       -u, --uid=
           Record events in threads owned by uid. Name or number.

       --filter-pids=
           Filter out events for these pids and for trace itself (comma separated list).

       -v, --verbose=
           Verbosity level.

       --no-inherit
           Child tasks do not inherit counters.

       -m, --mmap-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.

       -C, --cpu
           Collect samples 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. In
           per-thread mode with inheritance mode on (default), Events are captured only when the
           thread executes on the designated CPUs. Default is to monitor all CPUs.

       --duration: Show only events that had a duration greater than N.M ms.

       --sched: Accrue thread runtime and provide a summary at the end of the session.

       -i --input Process events from a given perf data file.

       -T --time Print full timestamp rather time relative to first sample.

       --comm
           Show process COMM right beside its ID, on by default, disable with --no-comm.

       -s, --summary
           Show only a summary of syscalls by thread with min, max, and average times (in msec)
           and relative stddev.

       -S, --with-summary
           Show all syscalls followed by a summary by thread with min, max, and average times (in
           msec) and relative stddev.

       --tool_stats
           Show tool stats such as number of times fd→pathname was discovered thru hooking the
           open syscall return + vfs_getname or via reading /proc/pid/fd, etc.

       -F=[all|min|maj], --pf=[all|min|maj]
           Trace pagefaults. Optionally, you can specify whether you want minor, major or all
           pagefaults. Default value is maj.

       --syscalls
           Trace system calls. This options is enabled by default.

       --event
           Trace other events, see perf list for a complete list.

       --proc-map-timeout
           When processing pre-existing threads /proc/XXX/mmap, it may take a long time, because
           the file may be huge. A time out is needed in such cases. This option sets the time
           out limit. The default value is 500 ms.

PAGEFAULTS

       When tracing pagefaults, the format of the trace is as follows:

       <min|maj>fault [<ip.symbol>+<ip.offset>] ⇒ <addr.dso@addr.offset[1]> (<map type><addr
       level>).

       •   min/maj indicates whether fault event is minor or major;

       •   ip.symbol shows symbol for instruction pointer (the code that generated the fault); if
           no debug symbols available, perf trace will print raw IP;

       •   addr.dso shows DSO for the faulted address;

       •   map type is either d for non-executable maps or x for executable maps;

       •   addr level is either k for kernel dso or .  for user dso.

       For symbols resolution you may need to install debugging symbols.

       Please be aware that duration is currently always 0 and doesn’t reflect actual time it
       took for fault to be handled!

       When --verbose specified, perf trace tries to print all available information for both IP
       and fault address in the form of dso@symbol[2]+offset.

EXAMPLES

       Trace only major pagefaults:

           $ perf trace --no-syscalls -F

       Trace syscalls, major and minor pagefaults:

           $ perf trace -F all

           1416.547 ( 0.000 ms): python/20235 majfault [CRYPTO_push_info_+0x0] => /lib/x86_64-linux-gnu/libcrypto.so.1.0.0@0x61be0 (x.)

           As you can see, there was major pagefault in python process, from
           CRYPTO_push_info_ routine which faulted somewhere in libcrypto.so.

SEE ALSO

       perf-record(1), perf-script(1)

NOTES

        1. addr.dso@addr.offset
           mailto:addr.dso@addr.offset

        2. dso@symbol
           mailto:dso@symbol