Source code of Windows XP (NT5)
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125 lines
3.6 KiB

//+---------------------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1995.
//
// File: Idle.cxx
//
// Contents: Idle time tracker.
//
// Classes: CIdleTime
//
// History: 15-Nov-95 KyleP Created
//
//----------------------------------------------------------------------------
#include <pch.cxx>
#pragma hdrstop
#include "idle.hxx"
//+---------------------------------------------------------------------------
//
// Member: CIdleTime::CIdleTime, private
//
// Effects: Initialize idle time tracker.
//
// History: 15-Nov-95 KyleP Created
//
//----------------------------------------------------------------------------
CIdleTime::CIdleTime()
: _liLastIdleTime( 0 ),
_liLastTotalTime( 0 ),
_cProcessors( 0 )
{
NTSTATUS status = NtQuerySystemInformation(
SystemProcessorPerformanceInformation,
_aProcessorTime,
sizeof(_aProcessorTime),
&_cProcessors );
if ( !NT_ERROR( status ) )
{
Win4Assert( _cProcessors % sizeof(_aProcessorTime[0]) == 0 );
_cProcessors = _cProcessors / sizeof(_aProcessorTime[0]);
for ( unsigned i = 0; i < _cProcessors; i++ )
{
_liLastIdleTime += _aProcessorTime[i].IdleTime.QuadPart;
_liLastTotalTime += _aProcessorTime[i].KernelTime.QuadPart + _aProcessorTime[i].UserTime.QuadPart;
}
//
// Don't check for overflow. This will overflow in about
// 58K years!
//
Win4Assert( _liLastIdleTime < 0x0FFFFFFFFFFFFFFF );
Win4Assert( _liLastTotalTime < 0x0FFFFFFFFFFFFFFF );
}
else
{
ciDebugOut(( DEB_ERROR, "NtQuerySystemInformation returned 0x%x\n", status ));
_cProcessors = 0;
}
}
//+---------------------------------------------------------------------------
//
// Member: CIdleTime::PercentIdle, private
//
// Returns: Percent idle time since last call to this method.
//
// History: 15-Nov-95 KyleP Created
//
//----------------------------------------------------------------------------
unsigned CIdleTime::PercentIdle()
{
unsigned pctIdle;
NTSTATUS status = NtQuerySystemInformation (
SystemProcessorPerformanceInformation,
_aProcessorTime,
sizeof(_aProcessorTime[0]) * _cProcessors,
0 );
if ( !NT_ERROR( status ) )
{
LONGLONG liIdleTime = 0;
LONGLONG liTotalTime = 0;
for ( unsigned i = 0; i < _cProcessors; i++ )
{
liIdleTime += _aProcessorTime[i].IdleTime.QuadPart;
liTotalTime += _aProcessorTime[i].KernelTime.QuadPart + _aProcessorTime[i].UserTime.QuadPart;
}
Win4Assert( liIdleTime >= _liLastIdleTime );
Win4Assert( liTotalTime >= _liLastTotalTime );
pctIdle = (unsigned)((liIdleTime - _liLastIdleTime) * 100 / (1 + liTotalTime - _liLastTotalTime));
_liLastIdleTime = liIdleTime;
_liLastTotalTime = liTotalTime;
//
// Don't check for overflow. This will overflow in about
// 58K years!
//
Win4Assert( _liLastIdleTime < 0x0FFFFFFFFFFFFFFF );
Win4Assert( _liLastTotalTime < 0x0FFFFFFFFFFFFFFF );
}
else
{
ciDebugOut(( DEB_ERROR, "NtQuerySystemInformation returned 0x%x\n", status ));
pctIdle = 0;
}
Win4Assert( pctIdle <= 100 );
return pctIdle;
}