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#include "cpuload.h"
#include <QFile>
#include <QDebug>
/*!
* \class CPULoad
* \brief CPULoad calculates the current CPU load.
*/
int CPULoad::m_forcedLoad = -1;
//! Constructor
CPULoad::CPULoad() :
m_load(-1)
{}
/*!
* Reads /proc/stat file
* ToDo: use sscanf if it faster
*/
CPULoad::TimeList CPULoad::readTimeList()
{
#ifdef Q_OS_LINUX
QFile fin(QStringLiteral("/proc/stat"));
if (fin.open(QIODevice::ReadOnly | QIODevice::Text))
return fin.readLine().split(' ');
#endif
return TimeList();
}
/*!
* Initialize. Currently only sets the value to -1.
*/
void CPULoad::init()
{
m_load = -1;
}
/*!
* Update the value.
* This must be called periodically (e.g. 1 - 5 seconds) in order to update the measurement.
* The data is obtained from first line of /proc/stat file
*/
void CPULoad::update()
{
// Read timing from the file
TimeList v(readTimeList());
if (m_timeList.length()) {
// Take delta with the previous timing
int sum = 0;
int idle = 0;
int iowait = 0;
int cpu = 0;
for (int i = 2; i < 7 && i < v.length(); i++)
sum += v.at(i).toInt() - m_timeList.at(i).toInt();
idle = v.at(5).toInt() - m_timeList.at(5).toInt();
iowait = v.at(6).toInt() - m_timeList.at(6).toInt();
cpu = sum - idle - iowait;
// Calculate load
m_load = 100.0 - (100.0 * idle / sum);
} else {
m_load = -1;
}
// Store the current timing
m_timeList = v;
}
/*!
* Returns The current value of the load in the range of 0 to 100
* or -1 if nothing measured.
*/
int CPULoad::cpuLoad() const
{
return m_forcedLoad > -1 ? m_forcedLoad : m_load;
}
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