linux/tools/perf/Documentation/perf-trace.txt
Arnaldo Carvalho de Melo c522739d72 perf trace: Use vfs_getname hook if available
Initially it tries to find a probe:vfs_getname that should be setup
with:

 perf probe 'vfs_getname=getname_flags:65 pathname=result->name:string'

or with slight changes to cope with code flux in the getname_flags code.

In the future, if a "vfs:getname" tracepoint becomes available, then it
will be preferred.

This is not strictly required and more expensive method of reading the
/proc/pid/fd/ symlink will be used when the fd->path array entry is not
populated by a previous vfs_getname + open syscall ret sequence.

As with any other 'perf probe' probe the setup must be done just once
and the probe will be left inactive, waiting for users, be it 'perf
trace' of any other tool.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-ujg8se8glq5izmu8cdkq15po@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-10-16 11:18:24 -03:00

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perf-trace(1)
=============
NAME
----
perf-trace - strace inspired tool
SYNOPSIS
--------
[verse]
'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:*').
Alernatively, the '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 events 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.
-v::
--verbose=::
Verbosity level.
-i::
--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.
--summary::
Show a summary of syscalls 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.
SEE ALSO
--------
linkperf:perf-record[1], linkperf:perf-script[1]