Add support for disabling background monitoring

This change adds a "Background monitoring" check box to the settings
dialog. This new check box is checked by default but can be unchecked
to disable most of the background monitoring threads, in order to
minimize how disruption of power measurements for light CPU loads, and
to allow long-term tracing without excessively draining power.

EventEmitter/EventEmitter.cpp

@@ -55,7 +55,7 @@ int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
 	CPowerStatusMonitor powerMonitor;
 	powerMonitor.SetPerfCounters(perfCounters);
 	if (bMonitorPowerStuff)
-		powerMonitor.StartThreads();
+		powerMonitor.StartThreads(CPowerStatusMonitor::MonitorType::HeavyLoad);
 
 	CCPUFrequencyMonitor CPUFrequencyMonitor;
 	if (bMonitorFrequencyStuff)

UIforETW/PowerStatus.cpp

@@ -39,7 +39,8 @@ limitations under the License.
 
 // This sampling frequency leads to roughly 20 context switches per second, which is
 // perhaps okay when tracing but must be avoided when tracing is not running.
-const int kSamplingInterval = 200;
+const int kHeavySamplingInterval = 200;
+const int kLightSamplingInterval = 1000;
 
 // These correspond to the funcID values returned by GetMsrFunc
 // They are documented here:
@@ -382,13 +383,19 @@ void CPowerStatusMonitor::PowerMonitorThread()
 	}
 
 	unsigned sampleNumber = 0;
+	DWORD samplingInterval = (monitorType_ == MonitorType::HeavyLoad) ?
+		kHeavySamplingInterval :
+		kLightSamplingInterval;
 	for (;;)
 	{
-		DWORD result = WaitForSingleObject(hExitEvent_, kSamplingInterval);
+		DWORD result = WaitForSingleObject(hExitEvent_, samplingInterval);
 		if (result == WAIT_OBJECT_0)
 			break;
 
-		SampleBatteryStat();
+		if (monitorType_ == MonitorType::HeavyLoad)
+		{
+			SampleBatteryStat();
+		}
 		SampleCPUPowerState();
 		SampleTimerState();
 
@@ -473,12 +480,13 @@ void CPowerStatusMonitor::SetPerfCounters(std::wstring& perfCounters)
 	}
 }
 
-void CPowerStatusMonitor::StartThreads()
+void CPowerStatusMonitor::StartThreads(MonitorType monitorType)
 {
 	UIETWASSERT(!hExitEvent_);
 
 	if (!hExitEvent_)
 	{
+		monitorType_ = monitorType;
 		hExitEvent_ = CreateEvent(nullptr, FALSE, FALSE, nullptr);
 		hThread_ = CreateThread(NULL, 0, StaticPowerMonitorThread, this, 0, nullptr);
 	}

UIforETW/PowerStatus.h

@@ -30,6 +30,11 @@ typedef int(*GetMaxTemperature_t)(int iNode, int* degreeC);
 class CPowerStatusMonitor
 {
 public:
+	enum class MonitorType
+	{
+		LightLoad,
+		HeavyLoad
+	};
 	CPowerStatusMonitor();
 	~CPowerStatusMonitor();
 
@@ -39,7 +44,7 @@ class CPowerStatusMonitor
 
 	// Start and stop the sampling threads so that they aren't running
 	// when tracing is not running.
-	void StartThreads();
+	void StartThreads(MonitorType monitorType);
 	void StopThreads();
 
 private:
@@ -53,6 +58,7 @@ class CPowerStatusMonitor
 
 	HANDLE hThread_ = nullptr;
 	HANDLE hExitEvent_ = nullptr;
+	MonitorType monitorType_ = MonitorType::HeavyLoad;
 
 	HMODULE energyLib_ = nullptr;
 	IntelEnergyLibInitialize_t IntelEnergyLibInitialize = nullptr;

UIforETW/Resource.h

@@ -77,6 +77,7 @@
 #define IDC_RECORD_PRE_TRACE            1039
 #define IDC_RECORD_PRE_TRACE2           1040
 #define IDC_IDENTIFY_CHROME_CPU         1040
+#define IDC_BACKGROUND_MONITORING       1041
 #define ID_TRACES_OPENTRACEINWPA        32771
 #define ID_TRACES_DELETETRACE           32772
 #define ID_TRACES_COMPRESSTRACE         32773

UIforETW/Settings.cpp

@@ -103,6 +103,7 @@ void CSettings::DoDataExchange(CDataExchange* pDX)
 	DDX_Control(pDX, IDC_CHECKFORNEWVERSIONS, btVersionChecks_);
 	DDX_Control(pDX, IDC_CHROME_CATEGORIES, btChromeCategories_);
 	DDX_Control(pDX, IDC_IDENTIFY_CHROME_CPU, btIdentifyChromeProcessesCPU_);
+	DDX_Control(pDX, IDC_BACKGROUND_MONITORING, btBackgroundMonitoring_);
 
 	CDialog::DoDataExchange(pDX);
 }
@@ -120,6 +121,7 @@ BEGIN_MESSAGE_MAP(CSettings, CDialog)
 	ON_BN_CLICKED(IDC_USE_OTHER_KERNEL_LOGGER, &CSettings::OnBnClickedUseOtherKernelLogger)
 	ON_BN_CLICKED(IDC_RECORD_PRE_TRACE, &CSettings::OnBnClickedRecordPreTrace)
 	ON_BN_CLICKED(IDC_IDENTIFY_CHROME_CPU, &CSettings::OnBnClickedIdentifyChromeCpu)
+	ON_BN_CLICKED(IDC_BACKGROUND_MONITORING, &CSettings::OnBnClickedBackgroundMonitoring)
 END_MESSAGE_MAP()
 
 BOOL CSettings::OnInitDialog()
@@ -128,6 +130,7 @@ BOOL CSettings::OnInitDialog()
 
 	SetDlgItemText(IDC_HEAPEXE, heapTracingExes_.c_str());
 	CheckDlgButton(IDC_USE_OTHER_KERNEL_LOGGER, bUseOtherKernelLogger_);
+	CheckDlgButton(IDC_BACKGROUND_MONITORING, bBackgroundTracing_);
 	CheckDlgButton(IDC_CHROMEDEVELOPER, bChromeDeveloper_);
 	CheckDlgButton(IDC_IDENTIFY_CHROME_CPU, bIdentifyChromeProcessesCPU_);
 	CheckDlgButton(IDC_AUTOVIEWTRACES, bAutoViewTraces_);
@@ -214,6 +217,10 @@ BOOL CSettings::OnInitDialog()
 		toolTip_.AddTool(&btIdentifyChromeProcessesCPU_, L"If this is checked and \"Chrome developer\" is "
 					L"checked then CPU usage details of Chrome processes will be added to the trace information "
 					L"file when traces are recorded. Calculating the CPU usage details can take a while.");
+		toolTip_.AddTool(&btBackgroundMonitoring_, L"When this is checked background threads will periodically "
+					L"(a few times per second) record information about system performance to the trace being "
+					L"recorded. This can be helpful in understanding performance problems but may affect "
+					L"power consumption.");
 	}
 
 	// Initialize the list of check boxes with all of the Chrome categories which
@@ -404,3 +411,9 @@ void CSettings::OnBnClickedRecordPreTrace()
 {
 	bRecordPreTrace_ = !bRecordPreTrace_;
 }
+
+
+void CSettings::OnBnClickedBackgroundMonitoring()
+{
+	bBackgroundTracing_ = !bBackgroundTracing_;
+}

UIforETW/Settings.h

@@ -41,6 +41,7 @@ class CSettings : public CDialog
 	std::wstring extraUserProviders_;
 	std::wstring perfCounters_;
 	bool bUseOtherKernelLogger_ = false;
+	bool bBackgroundTracing_ = true;
 	bool bChromeDeveloper_ = false;
 	bool bIdentifyChromeProcessesCPU_ = false;
 	bool bAutoViewTraces_ = false;
@@ -64,6 +65,7 @@ class CSettings : public CDialog
 	CButton btUseOtherKernelLogger_;
 	CButton btChromeDeveloper_;
 	CButton btIdentifyChromeProcessesCPU_;
+	CButton btBackgroundMonitoring_;
 	CButton btAutoViewTraces_;
 	CButton btRecordPreTrace_;
 	CButton btHeapStacks_;
@@ -96,4 +98,5 @@ class CSettings : public CDialog
 	afx_msg void OnBnClickedUseOtherKernelLogger();
 	afx_msg void OnBnClickedRecordPreTrace();
 	afx_msg void OnBnClickedIdentifyChromeCpu();
+	afx_msg void OnBnClickedBackgroundMonitoring();
 };

UIforETW/Support.cpp

@@ -65,6 +65,7 @@ void CUIforETWDlg::TransferSettings(bool saving)
 		{ L"CLRTracing", &bCLRTracing_ },
 		{ L"ShowCommands", &bShowCommands_ },
 		{ L"UseOtherKernelLogger", &bUseOtherKernelLogger_ },
+		{ L"BackgroundMonitoring", &bBackgroundMonitoring_ },
 		{ L"ChromeDeveloper", &bChromeDeveloper_ },
 		{ L"IdentifyChromeProcessesCPU", &bIdentifyChromeProcessesCPU_ },
 		{ L"AutoViewTraces", &bAutoViewTraces_ },

UIforETW/UIforETW.rc

@@ -129,7 +129,7 @@ BEGIN
     CONTROL         "Trace size:",IDC_TRACESIZE,"Static",SS_LEFTNOWORDWRAP | WS_GROUP,94,135,76,8
 END
 
-IDD_SETTINGS DIALOGEX 0, 0, 401, 197
+IDD_SETTINGS DIALOGEX 0, 0, 401, 203
 STYLE DS_SETFONT | DS_MODALFRAME | DS_FIXEDSYS | WS_POPUP | WS_CAPTION | WS_SYSMENU
 CAPTION "Settings"
 FONT 8, "MS Shell Dlg", 400, 0, 0x1
@@ -149,21 +149,23 @@ BEGIN
     CONTROL         "Perf counters:",IDC_STATIC,"Static",SS_LEFTNOWORDWRAP | WS_GROUP,7,112,52,8
     PUSHBUTTON      "Se&lect...",IDC_SELECT_PERF_COUNTERS,61,109,38,14
     EDITTEXT        IDC_PERFORMANCECOUNTERS,102,109,133,14,ES_AUTOHSCROLL
-    PUSHBUTTON      "&Copy startup profiles",IDC_COPYSTARTUPPROFILE,7,134,75,14
-    CONTROL         "&Identify Chrome CPU",IDC_IDENTIFY_CHROME_CPU,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,7,154,83,10
-    CONTROL         "Record pre-trace",IDC_RECORD_PRE_TRACE,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,7,167,71,10
+    PUSHBUTTON      "&Copy startup profiles",IDC_COPYSTARTUPPROFILE,7,126,75,14
+    CONTROL         "&Background monitoring",IDC_BACKGROUND_MONITORING,
+                    "Button",BS_AUTOCHECKBOX | WS_TABSTOP,7,147,89,10
+    CONTROL         "&Identify Chrome CPU",IDC_IDENTIFY_CHROME_CPU,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,7,160,83,10
+    CONTROL         "Record pre-trace",IDC_RECORD_PRE_TRACE,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,7,173,71,10
     CONTROL         "Use other kernel logger",IDC_USE_OTHER_KERNEL_LOGGER,
-                    "Button",BS_AUTOCHECKBOX | WS_TABSTOP,7,180,91,10
-    CONTROL         "Ch&rome developer",IDC_CHROMEDEVELOPER,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,103,128,75,10
-    CONTROL         "&Auto view traces",IDC_AUTOVIEWTRACES,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,103,141,70,10
-    CONTROL         "&Stacks on heap tracing",IDC_HEAPSTACKS,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,103,154,89,10
+                    "Button",BS_AUTOCHECKBOX | WS_TABSTOP,7,186,91,10
+    CONTROL         "Ch&rome developer",IDC_CHROMEDEVELOPER,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,103,134,75,10
+    CONTROL         "&Auto view traces",IDC_AUTOVIEWTRACES,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,103,147,70,10
+    CONTROL         "&Stacks on heap tracing",IDC_HEAPSTACKS,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,103,160,89,10
     CONTROL         "&VirtualAlloc stacks always",IDC_VIRTUALALLOCSTACKS,
-                    "Button",BS_AUTOCHECKBOX | WS_TABSTOP,103,167,97,10
-    CONTROL         "Check for new versions",IDC_CHECKFORNEWVERSIONS,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,103,180,105,10
+                    "Button",BS_AUTOCHECKBOX | WS_TABSTOP,103,173,97,10
+    CONTROL         "Check for new versions",IDC_CHECKFORNEWVERSIONS,"Button",BS_AUTOCHECKBOX | WS_TABSTOP,103,186,105,10
     CONTROL         "Chrome tracing cate&gories:",IDC_STATIC,"Static",SS_LEFTNOWORDWRAP | WS_GROUP,245,7,131,8
-    LISTBOX         IDC_CHROME_CATEGORIES,245,18,149,155,LBS_OWNERDRAWFIXED | LBS_HASSTRINGS | LBS_NOINTEGRALHEIGHT | LBS_DISABLENOSCROLL | WS_VSCROLL | WS_TABSTOP
-    DEFPUSHBUTTON   "OK",IDOK,286,176,50,14
-    PUSHBUTTON      "Cancel",IDCANCEL,344,176,50,14
+    LISTBOX         IDC_CHROME_CATEGORIES,245,18,149,162,LBS_OWNERDRAWFIXED | LBS_HASSTRINGS | LBS_NOINTEGRALHEIGHT | LBS_DISABLENOSCROLL | WS_VSCROLL | WS_TABSTOP
+    DEFPUSHBUTTON   "OK",IDOK,286,182,50,14
+    PUSHBUTTON      "Cancel",IDCANCEL,344,182,50,14
 END
 
 
@@ -235,7 +237,7 @@ BEGIN
         LEFTMARGIN, 7
         RIGHTMARGIN, 394
         TOPMARGIN, 7
-        BOTTOMMARGIN, 190
+        BOTTOMMARGIN, 196
     END
 END
 #endif    // APSTUDIO_INVOKED

UIforETW/UIforETWDlg.cpp

@@ -911,10 +911,15 @@ void CUIforETWDlg::StartEventThreads()
 	// that has run "too long". Checking every thirty seconds should be fine.
 	SetTimer(kTimerID, 30000, nullptr);
 
-	CPUFrequencyMonitor_.StartThreads();
+	if (bBackgroundMonitoring_)
+	{
+		CPUFrequencyMonitor_.StartThreads();
+		workingSetThread_.StartThreads();
+	}
 	PowerMonitor_.SetPerfCounters(perfCounters_);
-	PowerMonitor_.StartThreads();
-	workingSetThread_.StartThreads();
+	PowerMonitor_.StartThreads(bBackgroundMonitoring_ ?
+		CPowerStatusMonitor::MonitorType::HeavyLoad :
+		CPowerStatusMonitor::MonitorType::LightLoad);
 }
 
 void CUIforETWDlg::StopEventThreads()
@@ -1850,6 +1855,7 @@ void CUIforETWDlg::OnBnClickedSettings()
 	dlgSettings.extraUserProviders_ = extraUserProviders_;
 	dlgSettings.perfCounters_ = perfCounters_;
 	dlgSettings.bUseOtherKernelLogger_ = bUseOtherKernelLogger_;
+	dlgSettings.bBackgroundTracing_ = bBackgroundMonitoring_;
 	dlgSettings.bChromeDeveloper_ = bChromeDeveloper_;
 	dlgSettings.bIdentifyChromeProcessesCPU_ = bIdentifyChromeProcessesCPU_;
 	dlgSettings.bAutoViewTraces_ = bAutoViewTraces_;
@@ -1883,6 +1889,7 @@ void CUIforETWDlg::OnBnClickedSettings()
 		bIdentifyChromeProcessesCPU_ = dlgSettings.bIdentifyChromeProcessesCPU_;
 
 		// Copy over the remaining settings.
+		bBackgroundMonitoring_ = dlgSettings.bBackgroundTracing_;
 		bUseOtherKernelLogger_ = dlgSettings.bUseOtherKernelLogger_;
 		bRecordPreTrace_ = dlgSettings.bRecordPreTrace_;
 		WSMonitoredProcesses_ = dlgSettings.WSMonitoredProcesses_;

UIforETW/UIforETWDlg.h

@@ -223,6 +223,7 @@ class CUIforETWDlg : public CDialog
 	CToolTipCtrl toolTip_;
 
 	// Editable only by the settings dialog.
+	bool bBackgroundMonitoring_ = true;
 	bool bChromeDeveloper_ = false;
 	bool bIdentifyChromeProcessesCPU_ = false;
 	bool bAutoViewTraces_ = false;