alistair23-linux/tools/perf/Documentation/perf-diff.txt
Jiri Olsa 863e451f69 perf diff: Make diff command work with evsel hists
Putting 'perf diff' command back on track with the 'latest'
evsel hists changes. Each evsel has its own 'hists' object
gathering stats for the particular event.

While currently counts are accumulated for the whole session
regardless of the events diversification within compared
sessions.

The 'perf diff' command now outputs all matching events within
compared sessions (with event name specified). The per event
diff output stays the same.

  $ ./perf diff
  # Event 'cycles'
  #
  # Baseline  Delta          Shared Object                          Symbol
  # ........ ..........  .................  ..............................
  #
       0.00%    +15.14%  [kernel.kallsyms]  [k] __wake_up
       0.00%    +13.38%  [kernel.kallsyms]  [k] ext4fs_dirhash

... SNIP

       0.00%     +0.42%  [kernel.kallsyms]  [k] local_clock
       0.17%     -0.05%  [kernel.kallsyms]  [k] native_write_msr_safe

  # Event 'faults'
  #
  # Baseline  Delta          Shared Object                          Symbol
  # ........ ..........  .................  ..............................
  #
       0.00%    +79.12%  ld-2.15.so         [.] _dl_relocate_object
       0.00%    +11.62%  ld-2.15.so         [.] openaux

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1346946426-13496-2-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-09-07 21:44:02 -03:00

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perf-diff(1)
============
NAME
----
perf-diff - Read two perf.data files and display the differential profile
SYNOPSIS
--------
[verse]
'perf diff' [oldfile] [newfile]
DESCRIPTION
-----------
This command displays the performance difference amongst two perf.data files
captured via perf record.
If no parameters are passed it will assume perf.data.old and perf.data.
The differential profile is displayed only for events matching both
specified perf.data files.
OPTIONS
-------
-M::
--displacement::
Show position displacement relative to baseline.
-D::
--dump-raw-trace::
Dump raw trace in ASCII.
-m::
--modules::
Load module symbols. WARNING: use only with -k and LIVE kernel
-d::
--dsos=::
Only consider symbols in these dsos. CSV that understands
file://filename entries.
-C::
--comms=::
Only consider symbols in these comms. CSV that understands
file://filename entries.
-S::
--symbols=::
Only consider these symbols. CSV that understands
file://filename entries.
-s::
--sort=::
Sort by key(s): pid, comm, dso, symbol.
-t::
--field-separator=::
Use a special separator character and don't pad with spaces, replacing
all occurrences of this separator in symbol names (and other output)
with a '.' character, that thus it's the only non valid separator.
-v::
--verbose::
Be verbose, for instance, show the raw counts in addition to the
diff.
-f::
--force::
Don't complain, do it.
--symfs=<directory>::
Look for files with symbols relative to this directory.
SEE ALSO
--------
linkperf:perf-record[1]