diff options
Diffstat (limited to 'mozglue/baseprofiler/public/BaseProfilerState.h')
| -rw-r--r-- | mozglue/baseprofiler/public/BaseProfilerState.h | 386 |
1 files changed, 386 insertions, 0 deletions
diff --git a/mozglue/baseprofiler/public/BaseProfilerState.h b/mozglue/baseprofiler/public/BaseProfilerState.h new file mode 100644 index 0000000000..26988c25de --- /dev/null +++ b/mozglue/baseprofiler/public/BaseProfilerState.h @@ -0,0 +1,386 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +// The Gecko Profiler is an always-on profiler that takes fast and low overhead +// samples of the program execution using only userspace functionality for +// portability. The goal of this module is to provide performance data in a +// generic cross-platform way without requiring custom tools or kernel support. +// +// Samples are collected to form a timeline with optional timeline event +// (markers) used for filtering. The samples include both native stacks and +// platform-independent "label stack" frames. + +#ifndef BaseProfilerState_h +#define BaseProfilerState_h + +// This header contains most functions that give information about the Base +// Profiler: Whether it is active or not, paused, the selected features, and +// some generic process and thread information. +// It is safe to include unconditionally, but uses of structs and functions must +// be guarded by `#ifdef MOZ_GECKO_PROFILER`. + +#include "mozilla/BaseProfilerUtils.h" + +#ifndef MOZ_GECKO_PROFILER + +# define AUTO_PROFILER_STATS(name) + +namespace mozilla::baseprofiler { + +[[nodiscard]] inline bool profiler_is_active() { return false; } +[[nodiscard]] inline bool profiler_is_active_and_unpaused() { return false; } + +} // namespace mozilla::baseprofiler + +#else // !MOZ_GECKO_PROFILER + +# include "mozilla/Atomics.h" +# include "mozilla/Maybe.h" + +# include <stdint.h> +# include <string> + +// Uncomment the following line to display profiler runtime statistics at +// shutdown. +// # define PROFILER_RUNTIME_STATS + +# ifdef PROFILER_RUNTIME_STATS +# include "mozilla/TimeStamp.h" +# endif + +namespace mozilla::baseprofiler { + +# ifdef PROFILER_RUNTIME_STATS +// This class gathers durations and displays some basic stats when destroyed. +// It is intended to be used as a static variable (see `AUTO_PROFILER_STATS` +// below), to display stats at the end of the program. +class StaticBaseProfilerStats { + public: + explicit StaticBaseProfilerStats(const char* aName) : mName(aName) {} + + ~StaticBaseProfilerStats() { + // Using unsigned long long for computations and printfs. + using ULL = unsigned long long; + ULL n = static_cast<ULL>(mNumberDurations); + if (n != 0) { + ULL sumNs = static_cast<ULL>(mSumDurationsNs); + printf( + "[%d] Profiler stats `%s`: %llu ns / %llu = %llu ns, max %llu ns\n", + int(profiler_current_process_id().ToNumber()), mName, sumNs, n, + sumNs / n, static_cast<ULL>(mLongestDurationNs)); + } else { + printf("[%d] Profiler stats `%s`: (nothing)\n", + int(profiler_current_process_id().ToNumber()), mName); + } + } + + void AddDurationFrom(TimeStamp aStart) { + DurationNs duration = static_cast<DurationNs>( + (TimeStamp::Now() - aStart).ToMicroseconds() * 1000 + 0.5); + mSumDurationsNs += duration; + ++mNumberDurations; + // Update mLongestDurationNs if this one is longer. + for (;;) { + DurationNs longest = mLongestDurationNs; + if (MOZ_LIKELY(longest >= duration)) { + // This duration is not the longest, nothing to do. + break; + } + if (MOZ_LIKELY(mLongestDurationNs.compareExchange(longest, duration))) { + // Successfully updated `mLongestDurationNs` with the new value. + break; + } + // Otherwise someone else just updated `mLongestDurationNs`, we need to + // try again by looping. + } + } + + private: + using DurationNs = uint64_t; + using Count = uint32_t; + + Atomic<DurationNs> mSumDurationsNs{0}; + Atomic<DurationNs> mLongestDurationNs{0}; + Atomic<Count> mNumberDurations{0}; + const char* mName; +}; + +// RAII object that measure its scoped lifetime duration and reports it to a +// `StaticBaseProfilerStats`. +class MOZ_RAII AutoProfilerStats { + public: + explicit AutoProfilerStats(StaticBaseProfilerStats& aStats) + : mStats(aStats), mStart(TimeStamp::Now()) {} + + ~AutoProfilerStats() { mStats.AddDurationFrom(mStart); } + + private: + StaticBaseProfilerStats& mStats; + TimeStamp mStart; +}; + +// Macro that should be used to collect basic statistics from measurements of +// block durations, from where this macro is, until the end of its enclosing +// scope. The name is used in the static variable name and when displaying stats +// at the end of the program; Another location could use the same name but their +// stats will not be combined, so use different name if these locations should +// be distinguished. +# define AUTO_PROFILER_STATS(name) \ + static ::mozilla::baseprofiler::StaticBaseProfilerStats sStat##name( \ + #name); \ + ::mozilla::baseprofiler::AutoProfilerStats autoStat##name(sStat##name); + +# else // PROFILER_RUNTIME_STATS + +# define AUTO_PROFILER_STATS(name) + +# endif // PROFILER_RUNTIME_STATS else + +//--------------------------------------------------------------------------- +// Profiler features +//--------------------------------------------------------------------------- + +# if defined(__APPLE__) && defined(__aarch64__) +# define POWER_HELP "Sample per process power use" +# elif defined(__APPLE__) && defined(__x86_64__) +# define POWER_HELP \ + "Record the power used by the entire system with each sample." +# elif defined(__linux__) && defined(__x86_64__) +# define POWER_HELP \ + "Record the power used by the entire system with each sample. " \ + "Only available with Intel CPUs and requires setting " \ + "the sysctl kernel.perf_event_paranoid to 0." +# elif defined(_MSC_VER) +# define POWER_HELP \ + "Record the value of every energy meter available on the system with " \ + "each sample. Only available on Windows 11 with Intel CPUs." +# else +# define POWER_HELP "Not supported on this platform." +# endif + +// Higher-order macro containing all the feature info in one place. Define +// |MACRO| appropriately to extract the relevant parts. Note that the number +// values are used internally only and so can be changed without consequence. +// Any changes to this list should also be applied to the feature list in +// toolkit/components/extensions/schemas/geckoProfiler.json. +// *** Synchronize with lists in ProfilerState.h and geckoProfiler.json *** +# define BASE_PROFILER_FOR_EACH_FEATURE(MACRO) \ + MACRO(0, "java", Java, "Profile Java code, Android only") \ + \ + MACRO(1, "js", JS, \ + "Get the JS engine to expose the JS stack to the profiler") \ + \ + MACRO(2, "mainthreadio", MainThreadIO, "Add main thread file I/O") \ + \ + MACRO(3, "fileio", FileIO, \ + "Add file I/O from all profiled threads, implies mainthreadio") \ + \ + MACRO(4, "fileioall", FileIOAll, \ + "Add file I/O from all threads, implies fileio") \ + \ + MACRO(5, "noiostacks", NoIOStacks, \ + "File I/O markers do not capture stacks, to reduce overhead") \ + \ + MACRO(6, "screenshots", Screenshots, \ + "Take a snapshot of the window on every composition") \ + \ + MACRO(7, "seqstyle", SequentialStyle, \ + "Disable parallel traversal in styling") \ + \ + MACRO(8, "stackwalk", StackWalk, \ + "Walk the C++ stack, not available on all platforms") \ + \ + MACRO(9, "jsallocations", JSAllocations, \ + "Have the JavaScript engine track allocations") \ + \ + MACRO(10, "nostacksampling", NoStackSampling, \ + "Disable all stack sampling: Cancels \"js\", \"stackwalk\" and " \ + "labels") \ + \ + MACRO(11, "preferencereads", PreferenceReads, \ + "Track when preferences are read") \ + \ + MACRO(12, "nativeallocations", NativeAllocations, \ + "Collect the stacks from a smaller subset of all native " \ + "allocations, biasing towards collecting larger allocations") \ + \ + MACRO(13, "ipcmessages", IPCMessages, \ + "Have the IPC layer track cross-process messages") \ + \ + MACRO(14, "audiocallbacktracing", AudioCallbackTracing, \ + "Audio callback tracing") \ + \ + MACRO(15, "cpu", CPUUtilization, "CPU utilization") \ + \ + MACRO(16, "notimerresolutionchange", NoTimerResolutionChange, \ + "Do not adjust the timer resolution for fast sampling, so that " \ + "other Firefox timers do not get affected") \ + \ + MACRO(17, "cpuallthreads", CPUAllThreads, \ + "Sample the CPU utilization of all registered threads") \ + \ + MACRO(18, "samplingallthreads", SamplingAllThreads, \ + "Sample the stacks of all registered threads") \ + \ + MACRO(19, "markersallthreads", MarkersAllThreads, \ + "Record markers from all registered threads") \ + \ + MACRO(20, "unregisteredthreads", UnregisteredThreads, \ + "Discover and profile unregistered threads -- beware: expensive!") \ + \ + MACRO(21, "processcpu", ProcessCPU, \ + "Sample the CPU utilization of each process") \ + \ + MACRO(22, "power", Power, POWER_HELP) +// *** Synchronize with lists in ProfilerState.h and geckoProfiler.json *** + +struct ProfilerFeature { +# define DECLARE(n_, str_, Name_, desc_) \ + static constexpr uint32_t Name_ = (1u << n_); \ + [[nodiscard]] static constexpr bool Has##Name_(uint32_t aFeatures) { \ + return aFeatures & Name_; \ + } \ + static constexpr void Set##Name_(uint32_t& aFeatures) { \ + aFeatures |= Name_; \ + } \ + static constexpr void Clear##Name_(uint32_t& aFeatures) { \ + aFeatures &= ~Name_; \ + } + + // Define a bitfield constant, a getter, and two setters for each feature. + BASE_PROFILER_FOR_EACH_FEATURE(DECLARE) + +# undef DECLARE +}; + +namespace detail { + +// RacyFeatures is only defined in this header file so that its methods can +// be inlined into profiler_is_active(). Please do not use anything from the +// detail namespace outside the profiler. + +// Within the profiler's code, the preferred way to check profiler activeness +// and features is via ActivePS(). However, that requires locking gPSMutex. +// There are some hot operations where absolute precision isn't required, so we +// duplicate the activeness/feature state in a lock-free manner in this class. +class RacyFeatures { + public: + MFBT_API static void SetActive(uint32_t aFeatures); + + MFBT_API static void SetInactive(); + + MFBT_API static void SetPaused(); + + MFBT_API static void SetUnpaused(); + + MFBT_API static void SetSamplingPaused(); + + MFBT_API static void SetSamplingUnpaused(); + + [[nodiscard]] MFBT_API static bool IsActive(); + + [[nodiscard]] MFBT_API static bool IsActiveWithFeature(uint32_t aFeature); + + // True if profiler is active, and not fully paused. + // Note that periodic sampling *could* be paused! + [[nodiscard]] MFBT_API static bool IsActiveAndUnpaused(); + + // True if profiler is active, and sampling is not paused (though generic + // `SetPaused()` or specific `SetSamplingPaused()`). + [[nodiscard]] MFBT_API static bool IsActiveAndSamplingUnpaused(); + + private: + static constexpr uint32_t Active = 1u << 31; + static constexpr uint32_t Paused = 1u << 30; + static constexpr uint32_t SamplingPaused = 1u << 29; + +// Ensure Active/Paused don't overlap with any of the feature bits. +# define NO_OVERLAP(n_, str_, Name_, desc_) \ + static_assert(ProfilerFeature::Name_ != SamplingPaused, \ + "bad feature value"); + + BASE_PROFILER_FOR_EACH_FEATURE(NO_OVERLAP); + +# undef NO_OVERLAP + + // We combine the active bit with the feature bits so they can be read or + // written in a single atomic operation. + // TODO: Could this be MFBT_DATA for better inlining optimization? + static Atomic<uint32_t, MemoryOrdering::Relaxed> sActiveAndFeatures; +}; + +MFBT_API bool IsThreadBeingProfiled(); + +} // namespace detail + +//--------------------------------------------------------------------------- +// Get information from the profiler +//--------------------------------------------------------------------------- + +// Is the profiler active? Note: the return value of this function can become +// immediately out-of-date. E.g. the profile might be active but then +// profiler_stop() is called immediately afterward. One common and reasonable +// pattern of usage is the following: +// +// if (profiler_is_active()) { +// ExpensiveData expensiveData = CreateExpensiveData(); +// PROFILER_OPERATION(expensiveData); +// } +// +// where PROFILER_OPERATION is a no-op if the profiler is inactive. In this +// case the profiler_is_active() check is just an optimization -- it prevents +// us calling CreateExpensiveData() unnecessarily in most cases, but the +// expensive data will end up being created but not used if another thread +// stops the profiler between the CreateExpensiveData() and PROFILER_OPERATION +// calls. +[[nodiscard]] inline bool profiler_is_active() { + return baseprofiler::detail::RacyFeatures::IsActive(); +} + +// Same as profiler_is_active(), but also checks if the profiler is not paused. +[[nodiscard]] inline bool profiler_is_active_and_unpaused() { + return baseprofiler::detail::RacyFeatures::IsActiveAndUnpaused(); +} + +// Is the profiler active and unpaused, and is the current thread being +// profiled? (Same caveats and recommented usage as profiler_is_active().) +[[nodiscard]] inline bool profiler_thread_is_being_profiled() { + return baseprofiler::detail::RacyFeatures::IsActiveAndUnpaused() && + baseprofiler::detail::IsThreadBeingProfiled(); +} + +// Is the profiler active and paused? Returns false if the profiler is inactive. +[[nodiscard]] MFBT_API bool profiler_is_paused(); + +// Is the profiler active and sampling is paused? Returns false if the profiler +// is inactive. +[[nodiscard]] MFBT_API bool profiler_is_sampling_paused(); + +// Is the current thread sleeping? +[[nodiscard]] MFBT_API bool profiler_thread_is_sleeping(); + +// Get all the features supported by the profiler that are accepted by +// profiler_start(). The result is the same whether the profiler is active or +// not. +[[nodiscard]] MFBT_API uint32_t profiler_get_available_features(); + +// Check if a profiler feature (specified via the ProfilerFeature type) is +// active. Returns false if the profiler is inactive. Note: the return value +// can become immediately out-of-date, much like the return value of +// profiler_is_active(). +[[nodiscard]] MFBT_API bool profiler_feature_active(uint32_t aFeature); + +// Returns true if any of the profiler mutexes are currently locked *on the +// current thread*. This may be used by re-entrant code that may call profiler +// functions while the same of a different profiler mutex is locked, which could +// deadlock. +[[nodiscard]] bool profiler_is_locked_on_current_thread(); + +} // namespace mozilla::baseprofiler + +#endif // !MOZ_GECKO_PROFILER + +#endif // BaseProfilerState_h |