[RFC 00/12] perf diff: Factor diff command

From: Jiri Olsa
Date: Thu Sep 06 2012 - 11:47:44 EST

hi,
this patchset factors the perf diff command to be usable for
differential profiling following paper from Paul McKenney:
(thanks to Arnaldo for sharing it with me).

http://www2.rdrop.com/users/paulmck/scalability/paper/profiling.2002.06.04.pdf

The 'perf diff' and 'std/hist' code is now changed to allow computations
mentioned in the paper. Two of them are implemented within this patchset:
1) ratio differential profiling
2) weighted differential profiling

The standard ratio delta computation stays as default.

To sum it up:
- perf diff displays output for matching event pairs within 2 given perf.data files
- stdio ui code is factored to allow easy insertion of new data column
- added perf diff '-b' option to display only matched hist entries
(hist entries found in both files)
- added perf diff '-c' option to choose diff computation,
support for:
delta: the current default one
ratio: ratio differential profile
wdiff: weighted differential profile
- added perf diff '-c+' option to sort entries based on the computation data
- added perf diff '-F' option to show formula used to compute the data
- added perf diff '-p' option to display hist entries periods


Attached patches:
01/12 perf diff: Make diff command work with evsel hists
02/12 perf tools: Replace sort's standalone field_sep with symbol_conf.field_sep
03/12 perf hists: Add struct hists pointer to struct hist_entry
04/12 perf diff: Refactor diff displacement possition info
05/12 perf diff: Refactor stdio ui data columns output
06/12 perf diff: Add -b option for perf diff to display paired entries only
07/12 perf diff: Add ratio computation way to compare hist entries
08/12 perf diff: Add option to sort entries based on diff computation
09/12 perf diff: Add weighted diff computation way to compare hist entries
10/12 perf diff: Add -p option to display period values for hist entries
11/12 perf diff: Add -F option to display formula for computation
12/12 perf diff: Add -F option for ratio computation


I'm still testing this, trying to find out useful outputs/computations/options,
so looking for any ideas and recommendations ;)

thanks,
jirka


Eamples:

display default profile
-----------------------------------------------------------------------------------
$ ./perf diff
# Event 'cache-misses:u'
#
# Baseline Delta Shared Object Symbol
# ........ ........ .................. .................................
#
0.00% +63.54% libc-2.15.so [.] __dcigettext
0.00% +5.38% libc-2.15.so [.] _dl_addr
0.00% +5.30% libc-2.15.so [.] __register_atfork
0.31% +3.94% [kernel.kallsyms] [k] page_fault
0.00% +4.07% ld-2.15.so [.] check_match.11335
0.00% +3.65% ld-2.15.so [.] version_check_doit
0.00% +3.56% ld-2.15.so [.] _dl_fixup
0.00% +3.05% ld-2.15.so [.] _dl_map_object
0.00% +2.90% [kernel.kallsyms] [k] system_call
3.94% -1.53% [kernel.kallsyms] [k] device_not_available
0.00% +1.21% libc-2.15.so [.] __GI___libc_write
0.00% +0.54% libc-2.15.so [.] __memcpy_ssse3_back
0.00% +0.11% libc-2.15.so [.] execvp
7.71% -7.69% ld-2.15.so [.] _dl_start
0.03% -0.02% libpthread-2.15.so [.] __read_nocancel
0.20% -0.18% perf [.] perf_evlist__prepare_workload



display ratio profile
-----------------------------------------------------------------------------------
$ ./perf diff -cratio
# Event 'cache-misses:u'
#
# Baseline Ratio Shared Object Symbol
# ........ .............. .................. .................................
#
0.00% 0.000 libc-2.15.so [.] __dcigettext
0.00% 0.000 libc-2.15.so [.] _dl_addr
0.00% 0.000 libc-2.15.so [.] __register_atfork
0.31% 15.450 [kernel.kallsyms] [k] page_fault
0.00% 0.000 ld-2.15.so [.] check_match.11335
0.00% 0.000 ld-2.15.so [.] version_check_doit
0.00% 0.000 ld-2.15.so [.] _dl_fixup
0.00% 0.000 ld-2.15.so [.] _dl_map_object
0.00% 0.000 [kernel.kallsyms] [k] system_call
3.94% 0.678 [kernel.kallsyms] [k] device_not_available
0.00% 0.000 libc-2.15.so [.] __GI___libc_write
0.00% 0.000 libc-2.15.so [.] __memcpy_ssse3_back
0.00% 0.000 libc-2.15.so [.] execvp
7.71% 0.002 ld-2.15.so [.] _dl_start
0.03% 0.500 libpthread-2.15.so [.] __read_nocancel
0.20% 0.077 perf [.] perf_evlist__prepare_workload



display ratio profile only with entries matched in both files
-----------------------------------------------------------------------------------
$ ./perf diff -cratio -b

# Event 'cache-misses:u'
#
# Baseline Ratio Shared Object Symbol
# ........ .............. .................. .................................
#
0.31% 15.450 [kernel.kallsyms] [k] page_fault
3.94% 0.678 [kernel.kallsyms] [k] device_not_available
7.71% 0.002 ld-2.15.so [.] _dl_start
0.03% 0.500 libpthread-2.15.so [.] __read_nocancel
0.20% 0.077 perf [.] perf_evlist__prepare_workload



display ratio profile only with entries matched in both files and sorted
-----------------------------------------------------------------------------------
$ ./perf diff -c+ratio -b

# Event 'cache-misses:u'
#
# Baseline Ratio Shared Object Symbol
# ........ .............. .................. .................................
#
0.31% 15.450 [kernel.kallsyms] [k] page_fault
3.94% 0.678 [kernel.kallsyms] [k] device_not_available
0.03% 0.500 libpthread-2.15.so [.] __read_nocancel
0.20% 0.077 perf [.] perf_evlist__prepare_workload
7.71% 0.002 ld-2.15.so [.] _dl_start



display weighted profile with weights w1=1 w2=2, with formula, sorted, matching
entries only and with periods displayed
-----------------------------------------------------------------------------------
$ ./perf diff -c+wdiff:1,2 -F -b -p

# Baseline Weighted diff Formula Baseline Period Period Shared Object Symbol
# ........ ............. .................................................. ............... ............ .................. .................................
#
0.31% +598 (309 * 2) - (20 * 1) 20 309 [kernel.kallsyms] [k] page_fault
3.94% +92 (175 * 2) - (258 * 1) 258 175 [kernel.kallsyms] [k] device_not_available
0.03% +0 (1 * 2) - (2 * 1) 2 1 libpthread-2.15.so [.] __read_nocancel
0.20% -11 (1 * 2) - (13 * 1) 13 1 perf [.] perf_evlist__prepare_workload
7.71% -503 (1 * 2) - (505 * 1) 505 1 ld-2.15.so [.] _dl_start


Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>

---
tools/perf/Documentation/perf-diff.txt | 63 ++++++++++
tools/perf/builtin-diff.c | 488 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------
tools/perf/builtin-report.c | 6 +-
tools/perf/builtin-top.c | 6 +-
tools/perf/ui/stdio/hist.c | 574 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-----------------------------------
tools/perf/ui/stdio/hist.h | 26 ++++
tools/perf/util/evsel.h | 7 ++
tools/perf/util/hist.c | 7 +-
tools/perf/util/hist.h | 24 +++-
tools/perf/util/session.h | 4 +-
tools/perf/util/sort.c | 6 +-
tools/perf/util/sort.h | 22 +++-
12 files changed, 957 insertions(+), 276 deletions(-)
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