benchmark_HistogramRegistry.cxx

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// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.
 
#include "Framework/HistogramRegistry.h"
 
#include "TList.h"
 
#include <benchmark/benchmark.h>
#include <boost/format.hpp>
 
using namespace o2::framework;
using namespace arrow;
 
const int nLookups = 100000;
 
static void BM_HashedNameLookup(benchmark::State& state)
{
  for (auto _ : state) {
    state.PauseTiming();
    std::vector<HistogramSpec> histSpecs;
    for (auto i = 0; i < state.range(0); ++i) {
      histSpecs.push_back({fmt::format("histo{}", i + 1).c_str(), fmt::format("Histo {}", i + 1).c_str(), {HistType::kTH1F, {{100, 0, 1}}}});
    }
    HistogramRegistry registry{"registry", histSpecs};
    state.ResumeTiming();
 
    for (auto i = 0; i < nLookups; ++i) {
      auto x = registry.get<TH1>(HIST("histo4"));
      benchmark::DoNotOptimize(x);
    }
    state.counters["Average lookup distance"] = ((double)registry.lookup / (double)(state.range(0)));
  }
}
 
static void BM_StandardNameLookup(benchmark::State& state)
{
  for (auto _ : state) {
    state.PauseTiming();
    TList list;
    list.SetOwner();
    for (auto i = 1; i <= state.range(0); ++i) {
      list.Add(new TH1F((boost::format("histo%1%") % i).str().c_str(), (boost::format("Histo %1%") % i).str().c_str(), 100, 0, 1));
    }
    state.ResumeTiming();
 
    for (auto i = 0; i < nLookups; ++i) {
      auto x = list.FindObject("histo4");
      benchmark::DoNotOptimize(x);
    }
  }
}
BENCHMARK(BM_HashedNameLookup)->Arg(4)->Arg(8)->Arg(16)->Arg(64)->Arg(128)->Arg(256)->Arg(512);
BENCHMARK(BM_StandardNameLookup)->Arg(4)->Arg(8)->Arg(16)->Arg(64)->Arg(128)->Arg(256)->Arg(512);
 
BENCHMARK_MAIN();