perf, tools: Refactor and support interval and CSV metrics

[Andi Kleen]

Fixed last feedback.

[v5: Fix mainly bisect problems. No regressions introduced by one
patch and fixed again later. Some minor fixes in addition]
[v6: Fix running/noise printing patch.]
[v7: Reorder and merge two patches to avoid a bisect hole where unsupported was
printed as 0]
[v8: Minor fixes for review feedback. See changelog in patches.]
[v9: Fix newline bug. Add support for -A for --metric-only]
[v10: Remove extra "noise" printing (Jiri)
      Fix fields in documentation (Jiri)]
[v11: Fix manpage again. Avoid extra metric output in CSV mode.]
[v12: Move CSV metrics fields to after running/enabled/variance.
      Minor fixes.]
[v13: Address review comments. Now probe for stalled events 
      in advance to avoid empty columns or lines. Fix -A shadowing.
      Various minor changes. Drop merged patches.]
[v14: Fix empty lines with CSV metrics. Avoid one more empty column
      in metric-only.]

Currently perf stat does not support printing computed metrics for interval (-I xxx)
or CSV (-x,) mode. For example IPC or TSX metrics over time are quite useful to know.

This patch implements them. The main obstacle was that the
metrics printing was all open coded all over the metrics computation code.
The second patch refactors the metrics printing to work through call backs that
can be more easily changed. This also cleans up the metrics printing significantly.
The indentation is now handled through printf, no more need to manually count spaces.

Then based on that it implements metrics printing for CSV and interval mode,
and finally a --metric-only mode.

Example output:

% perf stat  -I1000 -a sleep 1
#          time              counts unit events                    metric                              multiplex
     1.001301370       12020.049593      task-clock (msec)                                             (100.00%)
     1.001301370              3,952      context-switches          #    0.329 K/sec                    (100.00%)
     1.001301370                 69      cpu-migrations            #    0.006 K/sec                    (100.00%)
     1.001301370                 76      page-faults               #    0.006 K/sec                  
     1.001301370        386,582,789      cycles                    #    0.032 GHz                      (100.00%)
     1.001301370        716,441,544      stalled-cycles-frontend   #  185.33% frontend cycles idle     (100.00%)
     1.001301370    <not supported>      stalled-cycles-backend   
     1.001301370        101,751,678      instructions              #    0.26  insn per cycle         
     1.001301370                                                   #    7.04  stalled cycles per insn  (100.00%)
     1.001301370         20,914,692      branches                  #    1.740 M/sec                    (100.00%)
     1.001301370          1,943,630      branch-misses             #    9.29% of all branches        

CSV mode:

% perf stat  -x, -I1000 -a sleep 1
     1.000982778,12006.549977,,task-clock,12006547787,100.00,,,,
     1.000982778,12822,,context-switches,12007100604,100.00,0.001,M/sec
     1.000982778,175,,cpu-migrations,12007180306,100.00,0.015,K/sec
     1.000982778,3404,,page-faults,12007185482,100.00,0.284,K/sec
     1.000982778,1930307489,,cycles,12007018233,100.00,0.161,GHz
     1.000982778,6971803638,,stalled-cycles-frontend,12006902870,100.00,361.18,frontend cycles idle
     1.000982778,464493941,,instructions,12006873327,100.00,0.24,insn per cycle
     1.000982778,,,,,,15.01,stalled cycles per insn
     1.000982778,86548409,,branches,12006758420,100.00,7.208,M/sec
     1.000982778,4933638,,branch-misses,12006648104,100.00,5.70,of all branches

Now includes metrics

Metric only mode:

Concicse information if you only care about computed metrics, not raw values

% perf stat --metric-only  -a -I 1000
         1.001452803 frontend cycles idle insn per cycle       stalled cycles per insn branch-misses of all branches
         1.001452803  158.91%               0.66                2.39                    2.92%
         2.002192321  180.63%               0.76                2.08                    2.96%
         3.003088282  150.59%               0.62                2.57                    2.84%
         4.004369835  196.20%               0.98                1.62                    3.79%
         5.005227314  231.98%               0.84                1.90                    4.71%


Metric only mode in CSV (flat format, easy to plot and analyze in statistical tools like JMP, R, pandas, gnuplot):

% perf stat -x, --metric-only  -a -I 1000
     1.001381652,frontend cycles idle,insn per cycle,stalled cycles per insn,branch-misses of all branches,
     1.001381652,173.32,0.83,2.09,1.73,
     2.002073343,199.47,1.07,1.60,2.14,
     3.002875524,109.52,0.22,7.83,1.63,
     4.003970059,132.10,0.17,10.85,1.51,
     5.004818754,181.60,0.22,8.87,2.22,


Available in
git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc-2.6 perf/stat-metrics-18