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perf_stats: Mark GetMeanFrametime() as const

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

11
src/core/perf_stats.h
View file

@ -30,7 +30,6 @@ struct PerfStatsResults {
class PerfStats {
public:
explicit PerfStats(u64 title_id);
~PerfStats();
using Clock = std::chrono::high_resolution_clock;
@ -42,18 +41,18 @@ public:
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
* useful for scaling inputs or outputs moving between the two time domains.
*/
double GetLastFrameTimeScale();
double GetLastFrameTimeScale() const;
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
u64 title_id{0};
@ -61,7 +60,7 @@ private:
std::size_t current_index{0};
/// Stores an hour of historical frametime data useful for processing and tracking performance
/// regressions with code changes.
std::array<double, 216000> perf_history = {};
std::array<double, 216000> perf_history{};
/// Point when the cumulative counters were reset
Clock::time_point reset_point = Clock::now();