feat add profiling

3party/cppuprofile/lib/util/cpumonitor.cpp

@@ -0,0 +1,100 @@
+// Software Name : cppuprofile
+// SPDX-FileCopyrightText: Copyright (c) 2022 Orange
+// SPDX-License-Identifier: BSD-3-Clause
+//
+// This software is distributed under the BSD License;
+// see the LICENSE file for more details.
+//
+// Author: Cédric CHEDALEUX <cedric.chedaleux@orange.com> et al.
+
+#include "cpumonitor.h"
+#include <fstream>
+#include <sstream>
+
+using namespace std;
+
+uprofile::CpuMonitor::CpuMonitor() :
+    m_nbCpus(getNumberOfCPUCores())
+{
+    m_lastIdleTimes.resize(m_nbCpus, 0);
+    m_lastTotalTimes.resize(m_nbCpus, 0);
+}
+
+uprofile::CpuMonitor::~CpuMonitor()
+{
+}
+
+size_t uprofile::CpuMonitor::getNumberOfCPUCores()
+{
+    size_t nbCores = 0;
+#if defined(__linux__)
+    ifstream meminfo("/proc/cpuinfo");
+    string str;
+    while (getline(meminfo, str)) {
+        if (str.rfind("processor", 0) == 0) {
+            nbCores++;
+        }
+    }
+#endif
+    return nbCores;
+}
+
+void uprofile::CpuMonitor::extractCpuTimes(const string& cpuInfo, size_t& idleTime, size_t& totalTime)
+{
+    // Remove 'cpu<index' word and
+    // extract the idle time and sum all other times
+    size_t spacePos = cpuInfo.find(' ');
+    if (spacePos == string::npos) {
+        return;
+    }
+
+    stringstream times(cpuInfo.substr(spacePos + 1));
+    int index = 0;
+    for (size_t time; times >> time; ++index) {
+        if (index == 3) { // idle time i s the 4th param
+            idleTime = time;
+        }
+        totalTime += time;
+    }
+}
+
+vector<float> uprofile::CpuMonitor::getUsage()
+{
+    vector<float> usages;
+#if defined(__linux__)
+    ifstream procStat("/proc/stat");
+    // /proc/stat dumps the following info:
+    //      user nice system idle iowait irq softirq
+    // cpu  2255 34 2290 22625563 6290 127 456
+    // cpu0 1132 34 1441 11311718 3675 127 438
+    // cpu1 1123 0 849 11313845 2614 0 18
+    // ...
+    // Each numbers represents the amount of time the CPU has spent performing
+    // different kind of work
+
+    for (size_t cpuIndex = 0; cpuIndex < m_nbCpus; ++cpuIndex) {
+        string cpuName("cpu");
+        cpuName += to_string(cpuIndex);
+
+        // Look in /proc/stack the CPU info
+        string line;
+        while (getline(procStat, line)) {
+            if (line.find(cpuName) != std::string::npos) {
+                size_t idleTime = 0, totalTime = 0;
+                extractCpuTimes(line, idleTime, totalTime);
+
+                // To compute CPU load, we compute the time the CPU has been idle since the last read.
+                float cpuLoad = 100.0 * (1.0 - (float)(idleTime - m_lastIdleTimes[cpuIndex]) / (totalTime - m_lastTotalTimes[cpuIndex]));
+                usages.push_back(cpuLoad);
+
+                // Save the times value for the next read
+                m_lastIdleTimes[cpuIndex] = idleTime;
+                m_lastTotalTimes[cpuIndex] = totalTime;
+                break;
+            }
+        }
+    }
+#endif
+
+    return usages;
+}