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* [PATCH v2 0/5] Don't compute events that won't be used in a metric.
@ 2020-11-18  5:03 Ian Rogers
  2020-11-18  5:03 ` [PATCH v2 1/5] perf metric: Restructure struct expr_parse_ctx Ian Rogers
                   ` (4 more replies)
  0 siblings, 5 replies; 9+ messages in thread
From: Ian Rogers @ 2020-11-18  5:03 UTC (permalink / raw)
  To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
	Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
	linux-kernel, Andi Kleen, Jin Yao, John Garry, Paul Clarke,
	kajoljain
  Cc: Stephane Eranian, Sandeep Dasgupta, linux-perf-users, Ian Rogers

    
For a metric like:
  EVENT1 if #smt_on else EVENT2
    
currently EVENT1 and EVENT2 will be measured and then when the metric
is reported EVENT1 or EVENT2 will be printed depending on the value
from smt_on() during the expr parsing. Computing both events is
unnecessary and can lead to multiplexing as discussed in this thread:
https://lore.kernel.org/lkml/20201110100346.2527031-1-irogers@google.com/

This change modifies expression parsing so that constants are
considered when building the set of ids (events) and only events not
contributing to a constant value are measured.

v2. is a rebase.

Ian Rogers (5):
  perf metric: Restructure struct expr_parse_ctx.
  perf metric: Use NAN for missing event IDs.
  perf metric: Rename expr__find_other.
  perf metric: Add utilities to work on ids map.
  perf metric: Don't compute unused events.

 tools/perf/tests/expr.c       | 148 ++++++++++-----
 tools/perf/tests/pmu-events.c |  42 +++--
 tools/perf/util/expr.c        | 136 ++++++++++++--
 tools/perf/util/expr.h        |  17 +-
 tools/perf/util/expr.l        |   9 -
 tools/perf/util/expr.y        | 343 +++++++++++++++++++++++++++-------
 tools/perf/util/metricgroup.c |  44 +++--
 tools/perf/util/stat-shadow.c |  54 ++++--
 8 files changed, 586 insertions(+), 207 deletions(-)

-- 
2.29.2.299.gdc1121823c-goog


^ permalink raw reply	[flat|nested] 9+ messages in thread

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Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
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2020-11-18  5:03 [PATCH v2 0/5] Don't compute events that won't be used in a metric Ian Rogers
2020-11-18  5:03 ` [PATCH v2 1/5] perf metric: Restructure struct expr_parse_ctx Ian Rogers
2020-11-18  5:03 ` [PATCH v2 2/5] perf metric: Use NAN for missing event IDs Ian Rogers
2020-11-19 19:47   ` Jiri Olsa
2020-11-18  5:03 ` [PATCH v2 3/5] perf metric: Rename expr__find_other Ian Rogers
2020-11-18  5:03 ` [PATCH v2 4/5] perf metric: Add utilities to work on ids map Ian Rogers
2020-11-18  5:03 ` [PATCH v2 5/5] perf metric: Don't compute unused events Ian Rogers
2020-11-19 20:59   ` Jiri Olsa
     [not found]     ` <CAP-5=fWjzwDg7SbfBq+mHqT+zDEEpei8M5AF8+Bk8sU19Ta_hg@mail.gmail.com>
2020-11-20 19:35       ` Jiri Olsa

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