Commit f85d120c authored by Ian Rogers's avatar Ian Rogers Committed by Arnaldo Carvalho de Melo
Browse files

perf jevents: Sort strings in the big C string to reduce faults 



Sort the strings within the big C string based on whether they were
for a metric and then by when they were added. This helps group
related strings and reduce minor faults by approximately 10 in 1740,
about 0.57%.

Signed-off-by: default avatarIan Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230824041330.266337-18-irogers@google.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 8d4b6d37

tools/perf/pmu-events/jevents.py

+23 −8
Original line number Diff line number Diff line
@@ -113,13 +113,24 @@ class BigCString: 
  strings: Set[str]

  big_string: Sequence[str]

  offsets: Dict[str, int]

  insert_number: int

  insert_point: Dict[str, int]

  metrics: Set[str]



  def __init__(self):

    self.strings = set()

    self.insert_number = 0;

    self.insert_point = {}

    self.metrics = set()



  def add(self, s: str) -> None:

  def add(self, s: str, metric: bool) -> None:

    """Called to add to the big string."""

    if s not in self.strings:

      self.strings.add(s)

      self.insert_point[s] = self.insert_number

      self.insert_number += 1

      if metric:

        self.metrics.add(s)



  def compute(self) -> None:

    """Called once all strings are added to compute the string and offsets."""
@@ -160,8 +171,11 @@ class BigCString: 
    self.big_string = []

    self.offsets = {}



    def string_cmp_key(s: str) -> Tuple[bool, int, str]:

      return (s in self.metrics, self.insert_point[s], s)



    # Emit all strings that aren't folded in a sorted manner.

    for s in sorted(self.strings):

    for s in sorted(self.strings, key=string_cmp_key):

      if s not in folded_strings:

        self.offsets[s] = big_string_offset

        self.big_string.append(f'/* offset={big_string_offset} */ "')
@@ -574,19 +588,20 @@ def preprocess_one_file(parents: Sequence[str], item: os.DirEntry) -> None: 
      assert len(mgroup) > 1, parents

      description = f"{metricgroup_descriptions[mgroup]}\\000"

      mgroup = f"{mgroup}\\000"

      _bcs.add(mgroup)

      _bcs.add(description)

      _bcs.add(mgroup, metric=True)

      _bcs.add(description, metric=True)

      _metricgroups[mgroup] = description

    return



  topic = get_topic(item.name)

  for event in read_json_events(item.path, topic):

    pmu_name = f"{event.pmu}\\000"

    _bcs.add(pmu_name)

    if event.name:

      _bcs.add(event.build_c_string(metric=False))

      _bcs.add(pmu_name, metric=False)

      _bcs.add(event.build_c_string(metric=False), metric=False)

    if event.metric_name:

      _bcs.add(event.build_c_string(metric=True))

      _bcs.add(pmu_name, metric=True)

      _bcs.add(event.build_c_string(metric=True), metric=True)



def process_one_file(parents: Sequence[str], item: os.DirEntry) -> None:

  """Process a JSON file during the main walk."""