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.orgSigned-off-by: 
Arnaldo Carvalho de Melo <acme@redhat.com>
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