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perf_stats: Mark GetMeanFrametime() as const

The general pattern is to mark mutexes as mutable when it comes to
matters of constness, given the mutex acts as a transient member of a
data structure.
This commit is contained in:
Lioncash 2020-08-03 08:12:03 -04:00
parent 05781ce8c4
commit d767be65be
2 changed files with 9 additions and 9 deletions

View file

@ -74,15 +74,16 @@ void PerfStats::EndGameFrame() {
game_frames += 1; game_frames += 1;
} }
double PerfStats::GetMeanFrametime() { double PerfStats::GetMeanFrametime() const {
std::lock_guard lock{object_mutex}; std::lock_guard lock{object_mutex};
if (current_index <= IgnoreFrames) { if (current_index <= IgnoreFrames) {
return 0; return 0;
} }
const double sum = std::accumulate(perf_history.begin() + IgnoreFrames, const double sum = std::accumulate(perf_history.begin() + IgnoreFrames,
perf_history.begin() + current_index, 0.0); perf_history.begin() + current_index, 0.0);
return sum / (current_index - IgnoreFrames); return sum / static_cast<double>(current_index - IgnoreFrames);
} }
PerfStatsResults PerfStats::GetAndResetStats(microseconds current_system_time_us) { PerfStatsResults PerfStats::GetAndResetStats(microseconds current_system_time_us) {
@ -111,7 +112,7 @@ PerfStatsResults PerfStats::GetAndResetStats(microseconds current_system_time_us
return results; return results;
} }
double PerfStats::GetLastFrameTimeScale() { double PerfStats::GetLastFrameTimeScale() const {
std::lock_guard lock{object_mutex}; std::lock_guard lock{object_mutex};
constexpr double FRAME_LENGTH = 1.0 / 60; constexpr double FRAME_LENGTH = 1.0 / 60;

View file

@ -30,7 +30,6 @@ struct PerfStatsResults {
class PerfStats { class PerfStats {
public: public:
explicit PerfStats(u64 title_id); explicit PerfStats(u64 title_id);
~PerfStats(); ~PerfStats();
using Clock = std::chrono::high_resolution_clock; using Clock = std::chrono::high_resolution_clock;
@ -42,18 +41,18 @@ public:
PerfStatsResults GetAndResetStats(std::chrono::microseconds current_system_time_us); PerfStatsResults GetAndResetStats(std::chrono::microseconds current_system_time_us);
/** /**
* Returns the Arthimetic Mean of all frametime values stored in the performance history. * Returns the arithmetic mean of all frametime values stored in the performance history.
*/ */
double GetMeanFrametime(); double GetMeanFrametime() const;
/** /**
* Gets the ratio between walltime and the emulated time of the previous system frame. This is * Gets the ratio between walltime and the emulated time of the previous system frame. This is
* useful for scaling inputs or outputs moving between the two time domains. * useful for scaling inputs or outputs moving between the two time domains.
*/ */
double GetLastFrameTimeScale(); double GetLastFrameTimeScale() const;
private: private:
std::mutex object_mutex{}; mutable std::mutex object_mutex;
/// Title ID for the game that is running. 0 if there is no game running yet /// Title ID for the game that is running. 0 if there is no game running yet
u64 title_id{0}; u64 title_id{0};
@ -61,7 +60,7 @@ private:
std::size_t current_index{0}; std::size_t current_index{0};
/// Stores an hour of historical frametime data useful for processing and tracking performance /// Stores an hour of historical frametime data useful for processing and tracking performance
/// regressions with code changes. /// regressions with code changes.
std::array<double, 216000> perf_history = {}; std::array<double, 216000> perf_history{};
/// Point when the cumulative counters were reset /// Point when the cumulative counters were reset
Clock::time_point reset_point = Clock::now(); Clock::time_point reset_point = Clock::now();