perf report: Add weight[123] output fields

perf report: Add weight[123] output fields

Add weight1, weight2 and weight3 fields to -F/--fields and their aliases
like 'ins_lat', 'p_stage_cyc' and 'retire_lat'.  Note that they are in
the sort keys too but the difference is that output fields will sum up
the weight values and display the average.

In the sort key, users can see the distribution of weight value and I
think it's confusing we have local vs. global weight for the same weight.

For example, I experiment with mem-loads events to get the weights.  On
my laptop, it seems only weight1 field is supported.

  $ perf mem record -- perf test -w noploop

Let's look at the noploop function only.  It has 7 samples.

  $ perf script -F event,ip,sym,weight | grep noploop
  # event                         weight     ip           sym
  cpu/mem-loads,ldlat=30/P:           43     55b3c122bffc noploop
  cpu/mem-loads,ldlat=30/P:           48     55b3c122bffc noploop
  cpu/mem-loads,ldlat=30/P:           38     55b3c122bffc noploop    <--- same weight
  cpu/mem-loads,ldlat=30/P:           38     55b3c122bffc noploop    <--- same weight
  cpu/mem-loads,ldlat=30/P:           59     55b3c122bffc noploop
  cpu/mem-loads,ldlat=30/P:           33     55b3c122bffc noploop
  cpu/mem-loads,ldlat=30/P:           38     55b3c122bffc noploop    <--- same weight

When you use the 'weight' sort key, it'd show entries with a separate
weight value separately.  Also note that the first entry has 3 samples
with weight value 38, so they are displayed together and the weight
value is the sum of 3 samples (114 = 38 * 3).

  $ perf report -n -s +weight | grep -e Weight -e noploop
  # Overhead  Samples  Command   Shared Object   Symbol         Weight
       0.53%        3     perf   perf            [.] noploop    114
       0.18%        1     perf   perf            [.] noploop    59
       0.18%        1     perf   perf            [.] noploop    48
       0.18%        1     perf   perf            [.] noploop    43
       0.18%        1     perf   perf            [.] noploop    33

If you use 'local_weight' sort key, you can see the actual weight.

  $ perf report -n -s +local_weight | grep -e Weight -e noploop
  # Overhead  Samples  Command   Shared Object   Symbol         Local Weight
       0.53%        3     perf   perf            [.] noploop    38
       0.18%        1     perf   perf            [.] noploop    59
       0.18%        1     perf   perf            [.] noploop    48
       0.18%        1     perf   perf            [.] noploop    43
       0.18%        1     perf   perf            [.] noploop    33

But when you use the -F/--field option instead, you can see the average
weight for the while noploop function (as it won't group samples by
weight value and use the default 'comm,dso,sym' sort keys).

  $ perf report -n -F +weight | grep -e Weight -e noploop
  Warning:
  --fields weight shows the average value unlike in the --sort key.
  # Overhead  Samples  Weight1  Command  Shared Object  Symbol
       1.23%        7     42.4  perf     perf           [.] noploop

The weight1 field shows the average value:
  (38 * 3 + 59 + 48 + 43 + 33) / 7 = 42.4

Also it'd show the warning that 'weight' field has the average value.
Using 'weight1' can remove the warning.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240411181718.2367948-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>