80 lines
2.5 KiB
C++
80 lines
2.5 KiB
C++
// Copyright 2004-present Facebook. All Rights Reserved.
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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) 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 of
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* a large number of small-ish calls. This is normally a problem for standard profilers
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* like Systrace because the overhead of the profiler itself skews the timings you
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* are able to collect. This is especially a problem when doing nested calls to
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* profiled functions, as the parent calls will contain the overhead of their profiling
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* plus the overhead of all their childrens' profiling.
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*
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* MicroProfiler attempts to be low overhead by 1) aggregating timings in memory and
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* 2) trying to remove estimated profiling overhead from the returned 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 average
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* cost of invoking the system clock. The former is subtracted out for each child
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* profiler section that is invoked within a parent profiler section. The latter is
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* 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 emitted
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* 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("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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} }
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