Performance of the system.threading.timers in windows service

vrushali katkade

15y6.7kC#

I have developed the windows service in C#.NET . In this, I have used system.threading.timer .
when i have start the 10 second interval timer there is some variation between the execution timing.
//code
public void SetTimers(int timer, DataRow row)
{
TimeSpan dueTime;
TimeSpan interval;
SetTimeIntervals(row, out dueTime, out interval); timer1[timer] = new System.Threading.Timer(databaseTrensfer, row, dueTime, interval);
}
public void databaseTrensfer()
{
//code
}
private void SetTimeIntervals(DataRow row, out TimeSpan tsDueTime, out TimeSpan tsPeriod)
{
string alarmType = Convert.ToString(row["EBase"]);
string EType = Convert.ToString(row["EType"]);
string EFrequency = Convert.ToString(row["EFrequncy"]);
if (alarmType == "Milisecond")
{
int frquency1 = Convert.ToInt32(row["Tfrquency"]);
tsDueTime = new TimeSpan(0, 0, 0, 0, frquency1);//frquency1=interval
tsPeriod = new TimeSpan(0, 0, 0, 0, frquency1);
}
else if (alarmType == "Second")
{
int frquency1 = Convert.ToInt32(row["Tfrquency"]);
tsDueTime = new TimeSpan(0, 0, 0, frquency1);
tsPeriod = new TimeSpan(0, 0, 0, frquency1);
}
else if (alarmType == "Once")
{
tsDueTime = new TimeSpan(0, 0, 0);
tsPeriod = new TimeSpan(0, 0, 0);
}
else if (alarmType == "Minute")
{
int frquency1 = Convert.ToInt32(row["Tfrquency"]);
tsDueTime = new TimeSpan(0, frquency1, 0);
tsPeriod = new TimeSpan(0, frquency1, 0);
}
else if (alarmType == "Hour")
{
int minute = 0;
int frquency1 = 1;
if (Convert.ToString(row["RelativeFactor"]) != "")
minute = Convert.ToInt32(row["RelativeFactor"]);
if (Convert.ToString(row["Tfrquency"]) != "")
frquency1 = Convert.ToInt32(row["Tfrquency"]);
tsDueTime = new TimeSpan(frquency1, minute, 0);
tsPeriod = new TimeSpan(frquency1, 0, 0);
}
else
{
tsDueTime = new TimeSpan();
tsPeriod = new TimeSpan();
}
}
i have pass the frequency to set the timer & start the number of timer simultaneously
my o/p
2011-08-22 13:42:08.0
2011-08-22 13:42:18.0
2011-08-22 13:42:28.0
2011-08-22 13:42:38.15
.
.
.
2011-08-22 14:28:38.984
2011-08-22 14:28:48.984
2011-08-22 14:28:59.15
2011-08-22 14:29:09.15
2011-08-22 14:29:19.15
.
.
2011-08-22 15:14:59.953
2011-08-22 15:15:09.968
2011-08-22 15:15:19.968
i got this o/p timer started at the 08 seconds of variation then shifting to the 09 second
why all timers are not executing in exact timing?
thanks in advance

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes15y ago
Accepted answer
The following attempts to resynchronize the timer with the system clock after each interval of a second or longer has elapsed.

The code is 'off the top of my head' and so might not be quite right:

// add these fields

private TimeSpan[] _interval;
private DateTime[] _startTime;

// when you create timer1 array, need to initialize the above arrays

int len = timer1.Length;
_interval = new TimeSpan[len];
_startTime = new DateTime[len];

// change SetTimers method as follows;

public void SetTimers(int timer, DataRow row)
{
TimeSpan dueTime;
TimeSpan interval;
SetTimeIntervals(row, out dueTime, out interval);

_interval[timer] = interval;
_startTime[timer] = DateTime.Now + dueTime;
object[] obj = new object[2]{row, timer};
timer1[timer] = new System.Threading.Timer(databaseTrensfer, obj, dueTime, interval);
}

// change databaseTrensfer method as follows

public void databaseTrensfer(object state)
{
object[] obj = (object[])state;
DataRow row = (DataRow)obj[0];
string alarmType = Convert.ToString(row["EBase"]);
if (alarmType != "Milisecond" && alarmType != "Once")
{
int timer = (int)obj[1];
DateTime dt = DateTime.Now;
long elapsedMs = Convert.ToInt64((dt - _startTime[timer]).TotalMilliseconds);
long intervalMs = Convert.ToInt64(_interval[timer].TotalMilliseconds);
long remainder = elapsedMs % intervalMs;
if (remainder != 0L)
{
timer1[timer].Change(_interval[timer] - TimeSpan.FromMilliseconds(remainder), _interval[timer]);
}
}
//code
}
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vrushali katkade15y ago
Thanks a lot... it's working fine
0
vrushali katkade15y ago
what is the procedure of the resynchronizing the timer with the system clock every minute ?
0
Vulpes15y ago
Well, the resolution of the System.Threading.Timer is about 10 to 20 ms, so I don't think it's an accuracy problem as such.

However, the operation of the timer may be affected by what else is running on the machine. The TimerCallback method runs on a threadpool thread and if other processes are making heavy use of the CPU and/or threadpool, obtaining a thread from the pool or a time-slice for that thread at the exact time it's needed may be difficult.

If the loss of accuracy is a problem, I'd try resynchronizing the timer with the system clock every minute, say.
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