Allow pushing process monitoring metrics from user code

CMakeLists.txt

@@ -182,6 +182,7 @@ set(EXAMPLES
   examples/6-Increment.cxx
   examples/7-InternalBenchamrk.cxx
   examples/8-DbFiller.cxx
+  examples/9-ProcessMonitoring.cxx
   examples/10-Buffering.cxx
 )
 

README.md

@@ -149,6 +149,12 @@ This feature provides basic performance status of the process. Note that is runs
 ```cpp
 enableProcessMonitoring([interval in seconds]);
 ```
+
+As an alternative, without a need of a new thread, user can manually trigger:
+```
+pushProcessMonitoringMetrics()
+```
+
 Following metrics are generated every time interval:
 CPU measurements:
  + **cpuUsedPercentage** - percentage of a core usage (kernel + user mode) over time interval

examples/9-ProcessMonitoring.cxx

@@ -0,0 +1,17 @@
+///
+/// \file 9-ProcessMonitoring.cxx
+/// \author Adam Wegrzynek <adam.wegrzynek@cern.ch>
+///
+
+#include "Monitoring/MonitoringFactory.h"
+
+using namespace o2::monitoring;
+
+int main()
+{
+  auto monitoring = MonitoringFactory::Get("influxdb-stdout://");
+  for (int i = 0; i < 5; i++) {
+    monitoring->pushProcessMonitoringMetrics();
+    std::this_thread::sleep_for(std::chrono::milliseconds(1000));
+  }
+}

include/Monitoring/Monitoring.h

@@ -88,10 +88,8 @@ class Monitoring
   /// \param value            tag value
   void addGlobalTag(tags::Key key, tags::Value value);
 
-  /// Returns a metric which will be periodically sent to backends
-  /// \param name 		metric name
-  /// \return 		periodically send metric
-  //ComplexMetric& getAutoPushMetric(std::string name, unsigned int interval = 1);
+  /// Allows user to push process monitoring metrics without having separate thread
+  void pushProcessMonitoringMetrics();
 
  private:
   /// Sends multiple (not related to each other) metrics

include/Monitoring/ProcessMonitor.h

@@ -57,8 +57,8 @@ class ProcessMonitor
 
   static std::vector<std::string> getAvailableMetricsNames();
   std::vector<Metric> getPerformanceMetrics();
+  std::vector<Metric> makeLastMeasurementAndGetMetrics();
 
- public:
   /// Prepares externam software commands (ps)
   ProcessMonitor();
 
@@ -73,7 +73,6 @@ class ProcessMonitor
   /// Retrievs total memory size from /proc/meminfo
   void setTotalMemory();
 
- private:
   static constexpr const char* metricsNames[] = {"memoryUsagePercentage", "virtualMemorySize", "residentSetSize",
                                                  "cpuUsedPercentage", "involuntaryContextSwitches", "voluntaryContextSwitches", "cpuUsedAbsolute",
                                                  "averageResidentSetSize", "averageVirtualMemorySize", "averageCpuUsedPercentage",
@@ -108,8 +107,6 @@ class ProcessMonitor
 
   /// Retrieves CPU usage (%) and number of context switches during the interval
   std::vector<Metric> getCpuAndContexts();
-
-  std::vector<Metric> makeLastMeasurementAndGetMetrics();
 };
 
 } // namespace monitoring

src/Monitoring.cxx

@@ -178,6 +178,11 @@ void Monitoring::send(Metric&& metric, DerivedMetricMode mode)
   transmit(std::move(metric));
 }
 
+void Monitoring::pushProcessMonitoringMetrics()
+{
+  transmit(mProcessMonitor->getPerformanceMetrics());
+}
+
 inline bool Monitoring::matchVerbosity(Verbosity backend, Verbosity metric)
 {
   return (static_cast<std::underlying_type<Verbosity>::type>(backend) >= static_cast<std::underlying_type<Verbosity>::type>(metric));

src/ProcessMonitor.cxx

@@ -22,11 +22,10 @@ namespace monitoring
 ProcessMonitor::ProcessMonitor()
 {
   mPid = static_cast<unsigned int>(::getpid());
-  mTimeLastRun = std::chrono::high_resolution_clock::now();
-  getrusage(RUSAGE_SELF, &mPreviousGetrUsage);
 #ifdef O2_MONITORING_OS_LINUX
   setTotalMemory();
 #endif
+  init();
 }
 
 void ProcessMonitor::init()