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Kernel+Profiler: Track lost time between profiler timer ticks

We can lose profiling timer events for a few reasons, for example
disabled interrupts or system slowness. This accounts for lost
time between CPU samples by adding a field lost_samples to each
profiling event which tracks how many samples were lost immediately
preceding the event.
This commit is contained in:
Gunnar Beutner 2021-05-13 22:14:07 +02:00 committed by Andreas Kling
parent 8614d18956
commit c41f13f10b
8 changed files with 30 additions and 11 deletions

View file

@ -228,6 +228,7 @@ Result<NonnullOwnPtr<Profile>, String> Profile::load_from_perfcore_file(const St
Event event;
event.timestamp = perf_event.get("timestamp").to_number<u64>();
event.lost_samples = perf_event.get("lost_samples").to_number<u32>();
event.type = perf_event.get("type").to_string();
event.pid = perf_event.get("pid").to_i32();
event.tid = perf_event.get("tid").to_i32();

View file

@ -166,6 +166,7 @@ public:
String executable;
int pid { 0 };
int tid { 0 };
u32 lost_samples { 0 };
bool in_kernel { false };
Vector<Frame> frames;
};

View file

@ -45,6 +45,8 @@ String SamplesModel::column_name(int column) const
return "TID";
case Column::ExecutableName:
return "Executable";
case Column::LostSamples:
return "Lost Samples";
case Column::InnermostStackFrame:
return "Innermost Frame";
default:
@ -81,6 +83,10 @@ GUI::Variant SamplesModel::data(const GUI::ModelIndex& index, GUI::ModelRole rol
return (u32)event.timestamp;
}
if (index.column() == Column::LostSamples) {
return event.lost_samples;
}
if (index.column() == Column::InnermostStackFrame) {
return event.frames.last().symbol;
}

View file

@ -25,6 +25,7 @@ public:
ProcessID,
ThreadID,
ExecutableName,
LostSamples,
InnermostStackFrame,
__Count
};

View file

@ -78,7 +78,7 @@ void TimelineTrack::paint_event(GUI::PaintEvent& event)
}
auto& histogram = event.in_kernel ? kernel_histogram : usermode_histogram;
histogram.insert(clamp_timestamp(event.timestamp), 1);
histogram.insert(clamp_timestamp(event.timestamp), 1 + event.lost_samples);
}
decltype(kernel_histogram.at(0)) max_value = 0;