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.

1 files changed, 6 insertions, 0 deletions

diff --git a/Userland/DevTools/Profiler/SamplesModel.cpp b/Userland/DevTools/Profiler/SamplesModel.cpp
index ce8161d343..af23693c70 100644
--- a/Userland/DevTools/Profiler/SamplesModel.cpp
+++ b/Userland/DevTools/Profiler/SamplesModel.cpp
@@ -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;
         }