[PATCH RFC 00/10] counter read during perf sampling

[kan . liang]

From: Kan Liang <kan.liang@xxxxxxxxx>

The patch series intends to read counter statistics with fixed frequency
during sampling. The instant benefit is that we can read memory bandwidth
from uncore event during cpu PMU event is sampling.

Introduce 'C' event/group modifier. The event with this modifier
will do counting not sampling. If a group with this modifier, only
group leader do sampling. The counter statistics will be wrote in
new RECORD type PERF_RECORD_COUNTER_READ and stored in perf.data.
So perf report can present the counter statistics data accordingly.

There may be an alternative way to get counter statistics during
sampling by running perf record and perf stat together by script.
But the script way have various issue and complex to parses the
output.

Example:

 $perf record -e 'cycles,uncore_imc_1/cas_count_read/C'
  --counter-read-interval 10 -a ./tchain_edit
 [ perf record: Woken up 438 times to write data ]
 [ perf record: Captured and wrote 1.232 MB perf.data (17901 samples) ]


 $perf report -D

 0x3cae0 [0x28]: PERF_RECORD_COUNTER_READ: uncore_imc_1/cas_count_read/C
                CPU 0: val 1205 ena 2046148 run 2046148

 0x3cb08 [0x28]: PERF_RECORD_COUNTER_READ: uncore_imc_1/cas_count_read/C
                CPU 18: val 1315 ena 2001918 run 2001918

 0x3dba0 [0x28]: PERF_RECORD_COUNTER_READ: uncore_imc_1/cas_count_read/C
                CPU 0: val 1588 ena 12191520 run 12191520

 0x3dbc8 [0x28]: PERF_RECORD_COUNTER_READ: uncore_imc_1/cas_count_read/C
                CPU 18: val 1686 ena 12162202 run 12162202

 $perf report --stdio --socket-filter 0

 # To display the perf.data header info, please use --header/--header-only options.
 #
 #
 # Total Lost Samples: 0
 #
 # Samples: 17K of event 'cycles'
 # Event count (approx.): 10119095556
 # Processor Socket: 0
 #
 # Overhead  Command       Shared Object        Symbol
 # ........  ............  ...................  ..................................
 #
    97.68%  tchain_edit   tchain_edit          [.] f3
     0.07%  tchain_edit   tchain_edit          [.] f2
     0.04%  swapper       [kernel.vmlinux]     [k] run_timer_softirq
     0.04%  swapper       [kernel.vmlinux]     [k] find_busiest_group

 # Samples: 0  of event 'uncore_imc_1/cas_count_read/C'
 # Event count (approx.): 0
 # Processor Socket: 0
 # uncore_imc_1/cas_count_read/C: 35937


Kan Liang (10):
  perf,tools: Add 'C' event/group modifier
  perf,tools: Enable counter statistic read for perf record
  perf,tools: don't validate counter read event
  perf,tools: New RECORD type PERF_RECORD_COUNTER_READ
  perf,tools: record counter statistics during sampling
  perf,tools: option to set counter read interval
  perf,report: handle PERF_RECORD_COUNTER_READ
  perf,tools: store counter val in events_stats
  perf,tools: show counter read result in studio
  perf,tools: show counter read result in tui browser title

 tools/perf/Documentation/perf-list.txt   |   5 ++
 tools/perf/Documentation/perf-record.txt |   8 +++
 tools/perf/builtin-record.c              |  73 ++++++++++++++++++++++
 tools/perf/builtin-report.c              | 101 ++++++++++++++++++++++++++++++-
 tools/perf/ui/browsers/hists.c           |  37 +++++++++++
 tools/perf/util/event.c                  |   1 +
 tools/perf/util/event.h                  |  21 +++++++
 tools/perf/util/evlist.c                 |  20 ++++++
 tools/perf/util/evsel.c                  |  29 +++++++++
 tools/perf/util/evsel.h                  |   1 +
 tools/perf/util/parse-events.c           |   8 ++-
 tools/perf/util/parse-events.l           |   2 +-
 tools/perf/util/record.c                 |   6 +-
 tools/perf/util/session.c                |  16 +++++
 tools/perf/util/tool.h                   |   1 +
 15 files changed, 324 insertions(+), 5 deletions(-)

-- 
1.8.3.1

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