improve zenserver startup time (#879)

- Improvement: Lazy initialize CpuSampler - reduces startup time by ~600 ms
- Bugfix: Don't try to wipe .sentry-native folder at missing manifest - sentry is already running. Reduces startup time by ~450 ms when data folder is empty

1 files changed, 21 insertions, 11 deletions

diff --git a/src/zencore/system.cpp b/src/zencore/system.cpp
index 8985a8a76..23178814c 100644
--- a/src/zencore/system.cpp
+++ b/src/zencore/system.cpp
@@ -445,23 +445,15 @@ struct CpuSampler
 	PDH_HQUERY		   QueryHandle		 = nullptr;
 	PDH_HCOUNTER	   CounterHandle	 = nullptr;
 	bool			   HasPreviousSample = false;
+	bool			   IsInitialized	 = false;
 	bool			   IsWine			 = false;
 	ProcStatCpuSampler ProcStat{"Z:\\proc\\stat"};
 
 	CpuSampler()
 	{
 		IsWine = zen::windows::IsRunningOnWine();
-
-		if (!IsWine)
-		{
-			if (PdhOpenQueryW(nullptr, 0, &QueryHandle) == ERROR_SUCCESS)
-			{
-				if (PdhAddEnglishCounterW(QueryHandle, L"\\Processor(_Total)\\% Processor Time", 0, &CounterHandle) != ERROR_SUCCESS)
-				{
-					CounterHandle = nullptr;
-				}
-			}
-		}
+		// PDH initialization is deferred to the first Sample() call because
+		// PdhAddEnglishCounterW can take hundreds of milliseconds on first invocation.
 	}
 
 	~CpuSampler()
@@ -472,6 +464,22 @@ struct CpuSampler
 		}
 	}
 
+	void InitializePdh()
+	{
+		if (IsInitialized)
+		{
+			return;
+		}
+		IsInitialized = true;
+		if (PdhOpenQueryW(nullptr, 0, &QueryHandle) == ERROR_SUCCESS)
+		{
+			if (PdhAddEnglishCounterW(QueryHandle, L"\\Processor(_Total)\\% Processor Time", 0, &CounterHandle) != ERROR_SUCCESS)
+			{
+				CounterHandle = nullptr;
+			}
+		}
+	}
+
 	float Sample()
 	{
 		if (IsWine)
@@ -479,6 +487,8 @@ struct CpuSampler
 			return ProcStat.Sample();
 		}
 
+		InitializePdh();
+
 		if (!QueryHandle || !CounterHandle)
 		{
 			return 0.0f;