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Environment.TickCount vs DateTime.Now

Asked 2008-10-28T13:40:20.293
78

Is it ever OK to use Environment.TickCount to calculate time spans?

int start = Environment.TickCount;
// Do stuff
int duration = Environment.TickCount - start;
Console.WriteLine("That took " + duration " ms");

Because TickCount is signed and will rollover after 25 days (it takes 50 days to hit all 32 bits, but you have to scrap the signed bit if you want to make any sense of the math), it seems like it's too risky to be useful.

I'm using DateTime.Now instead. Is this the best way to do this?

DateTime start = DateTime.Now;
// Do stuff
TimeSpan duration = DateTime.Now - start;
Console.WriteLine("That took " + duration.TotalMilliseconds + " ms");
c# .net datetime timespan
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2 Answers

9

If you're looking for the functionality of Environment.TickCount but without the overhead of creating new Stopwatch objects, you can use the static Stopwatch.GetTimestamp() method (along with Stopwatch.Frequency) to calculate long time spans. Because GetTimestamp() returns a long, it won't overflow for a very, very long time (over 100,000 years, on the machine I'm using to write this). It's also much more accurate than Environment.TickCount which has a maximum resolution of 10 to 16 milliseconds.

answered 2011-06-10T15:37:18.400
0

I use Environment.TickCount because:

  1. The Stopwatch class is not in the Compact Framework.
  2. Stopwatch uses the same underlying timing mechanism as TickCount, so the results won't be any more or less accurate.
  3. The wrap-around problem with TickCount is cosmically unlikely to be hit (you'd have to leave your computer running for 27 days and then try to measure a time that just happens to span the wrap-around moment), and even if you did hit it the result would be a huge negative time span (so it would kind of stand out).

That being said, I would also recommend using Stopwatch, if it's available to you. Or you could take about 1 minute and write a Stopwatch-like class that wraps Environment.TickCount.

BTW, I see nothing in the Stopwatch documentation that mentions the wrap-around problem with the underlying timer mechanism, so I wouldn't be surprised at all to find that Stopwatch suffers from the same problem. But again, I wouldn't spend any time worrying about it.

answered 2008-10-28T14:23:06.260

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