90 строки
2.7 KiB
C++
90 строки
2.7 KiB
C++
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#pragma once
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#include <atomic>
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#include <thread>
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// #define WITH_MICRO_PROFILER 1
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#ifdef WITH_MICRO_PROFILER
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#define MICRO_PROFILER_SECTION(name) MicroProfilerSection __b(name)
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#define MICRO_PROFILER_SECTION_NAMED(var_name, name) \
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MicroProfilerSection var_name(name)
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#else
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#define MICRO_PROFILER_SECTION(name)
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#define MICRO_PROFILER_SECTION_NAMED(var_name, name)
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#endif
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namespace facebook {
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namespace react {
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enum MicroProfilerName {
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__INTERNAL_BENCHMARK_INNER,
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__INTERNAL_BENCHMARK_OUTER,
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__LENGTH__,
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};
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/**
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* MicroProfiler is a performance profiler for measuring the cumulative impact
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* of a large number of small-ish calls. This is normally a problem for standard
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* profilers like Systrace because the overhead of the profiler itself skews the
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* timings you are able to collect. This is especially a problem when doing
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* nested calls to profiled functions, as the parent calls will contain the
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* overhead of their profiling plus the overhead of all their childrens'
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* profiling.
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*
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* MicroProfiler attempts to be low overhead by 1) aggregating timings in memory
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* and 2) trying to remove estimated profiling overhead from the returned
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* timings.
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*
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* To remove estimated overhead, at the beginning of each trace we calculate the
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* average cost of profiling a no-op code section, as well as invoking the
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* average cost of invoking the system clock. The former is subtracted out for
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* each child profiler section that is invoked within a parent profiler section.
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* The latter is subtracted from each section, child or not.
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*
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* After MicroProfiler::stopProfiling() is called, a table of tracing data is
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* emitted to glog (which shows up in logcat on Android).
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*/
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struct MicroProfiler {
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static const char *profilingNameToString(MicroProfilerName name) {
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switch (name) {
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case __INTERNAL_BENCHMARK_INNER:
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return "__INTERNAL_BENCHMARK_INNER";
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case __INTERNAL_BENCHMARK_OUTER:
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return "__INTERNAL_BENCHMARK_OUTER";
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case __LENGTH__:
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throw std::runtime_error("__LENGTH__ has no name");
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default:
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throw std::runtime_error(
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"Trying to convert unknown MicroProfilerName to string");
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}
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}
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static void startProfiling();
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static void stopProfiling();
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static bool isProfiling();
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static void runInternalBenchmark();
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};
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class MicroProfilerSection {
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public:
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MicroProfilerSection(MicroProfilerName name);
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~MicroProfilerSection();
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private:
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bool isProfiling_;
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MicroProfilerName name_;
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uint_fast64_t startTime_;
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uint_fast32_t startNumProfileSections_;
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};
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} // namespace react
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} // namespace facebook
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