Download Stopwatch Video

[Hebe Zuelke]

Theonline stopwatch counts the time to the millisecond that passes after you click the "Start" button. It allows you to add laps. If you close the stopwatch, the value and laps will be automatically saved. If the period is sufficiently large, the number of days passed will be displayed, too.

Click the "Start" or "Stop" buttons to start or stop the stopwatch. Click the "Lap" button to add one lap and the current stopwatch value to the lap list. To reset laps and the stopwatch value, click the "Reset" button (the button appears when the stopwatch is stopped).

To clarify my concerns, stopwatch benchmarking is subject to error due to operating system scheduling. On a given run of your program the OS might schedule another process (or several) in the middle of the function you're timing. In Java, things are even a little bit worse if you're trying to time a threaded application, as the JVM scheduler throws even a little bit more randomness into the mix.

Stopwatch benchmarking is fine, provided you measure enough iterations to be meaningful. Typically, I require a total elapsed time of some number of single digit seconds. Otherwise, your results are easily significantly skewed by scheduling, and other O/S interruptions to your process.

For the profiling work I have used jProfiler for a number of years and have found it very good. I have recently looked over YourKit, which seems great from the WebSite, but I've not used it at all, personally.

To answer the question on scheduling interruptions, I find that doing repeated runs until consistency is achieved/observed works in practice to weed out anomalous results from process scheduling. I also find that thread scheduling has no practical impact for runs of between 5 and 30 seconds. Lastly, after you pass the few seconds threshold scheduling has, in my experience, negligible impact on the results - I find that a 5 second run consistently averages out the same as a 5 minute run for time/iteration.

It is not always possible to obtain this time using the available tools, for instance most testing tools do not include the time it takes for a browser to render a page so an overcomplex page with badly written css will show sub second response times to the testing tools, but, 5 seconds plus response time to the user.

You need to test a realistic number of iterations as you will get different answers depending on how you test the timing. If you only perform an operation once, it could be misleading to take the average of many iterations. If you want to know the time it takes after the JVM has warmed up you might run many (e.g. 10,000) iterations which are not included in the timings.

I also suggest you use System.nanoTime() as it's much more accurate. If your test time is around 10 micro-seconds or less, you don't want to call this too often or it can change your result. (e.g. If I am testing for say 5 seconds and I want to know when this is up I only get the nanoTime every 1000 iterations, if I know an iteration is very quick)

Profilers can get in the way of timings, so I would use a combination of stopwatch timing to identify overall performance problems, then use the profiler to work out where the time is being spent. Repeat the process as required.

Usually what's most important to optimize is whatever interferes with the user experience - which is most often a function of how frequently you perform the action, and whatever else is going on at the same time. Other forms of benchmarking often just help zero in on these.

I sometimes even use physical stopwatch measurements to see if something takes minutes, hours, days, or even weeks to compute (I am working with an application where run times on the orders of several days are not unheard of, even if seconds and minutes are the most common time spans).

However, the automation afforded by calls to any kind of clock system on the computer, like the java millis call referred to in the linked article, is clearly superior to manually seeing how long something runs.

Profilers are nice, when they work, but I have had problems applying them to our application, which usually involves dynamic code generation, dynamic loading of DLLs, and work performed in the two built-in just-in-time-compiled scripting languages of my application. They are quite often limited to assuming a single source language and other unrealistic expectations for complex software.

I ran a program today that searched through and collected information from a bunch of dBase files, it took just over an hour to run. I took a look at the code, made an educated guess at what the bottleneck was, made a minor improvement to the algorithm, and re-ran the program, this time it completed in 2.5 minutes.

I didn't need any fancy profiling tools or benchmark suites to tell me the new version was a significant improvement. If I needed to further optimize the running time I probably would have done some more sophisticated analysis but this wasn't necessary. I find that this sort of "stopwatch benchmarking" is an acceptable solution in quite a number of cases and resorting to more advanced tools would actually be more time-consuming in these cases.

I don't think stopwatch benchmarking is too horrible, but if you can get onto a Solaris or OS X machine you should check out DTrace. I've used it to get some great information about timing in my applications.

I want to know what should I add in the end of this output. Is it ms (01:20:17.0550410ms) or just s (01:20:17.0550410s)?And further more if I want to take only the msportion of this output and do some calculation with it which value should I take, is it .0550410 or 55.041? My questions might sound silly but I'm really confused!please help.

A Stopwatch instance can measure elapsed time for one interval, or the total of elapsed time across multiple intervals. In a typical Stopwatch scenario, you call the Start method, then eventually call the Stop method, and then you check elapsed time using the Elapsed property.

Before we begin looking at the Properties of the Stopwatch, we need to understand that in order for the Stopwatch to work, there needs to be a way to store a Magnitude of Time (information). A Magnitude of Time in this case a numerical representation of the difference between two points in time; in this case the when the Stopwatch Starts and when the Stopwatch Ends. Microsoft .Net has created a structure called TimeSpan to store this value.

It should be obvious that 01 is hours, 20 is minutes, 17 is seconds and .0550410 are tenths of seconds (decisecond). Adding any string values at the end will most likely make no sense because all the numbers are of different time durations. The only way I think it would make sense if you wanted be more specific is to change it to:

Elasped is a TimeSpan, what you're showing is the representation from writing it to the console (Same as calling .ToString() on any non string object), that representation is in hours:minutes:seconds.fraction of second. If you want to show this in a specific amount there are properties for this on the TimeSpan so instead of doing

It looks like you are just using the default .ToString() method of the Stopwatch.Elapsed property, which actually is a TimeSpan object. You can absolutely control the string formatting of this TimeSpan, as well as use numeric components of it for mathematical operations (rounding, adding, etc.). Please read this: Stopwatch.Elapsed Property

A quick search of 'c# stopwatch' returns the MSDN documentation showing that Stopwatch.Elapsed is a TimeSpan. Then a search on 'c# TimeSpan' returns the MSDN documentation showing that TimeSpan.ToString() returns a string with the following format: [-][d.]hh:mm:ss[.fffffff]. And that's just using google. Next time try doing some research before asking your question.

I prepared one glide table which has only one column. It has 5 items.

I create the page like this: when I chose one title item from 5 items on page A, detail page appears, and I added the stopwatch component there.

As @Darren_Murphy pointed out, the stopwatch REQUIRES 2 columns to function correctly. It requires one column to temporarily hold the start time and another column to temporarily hold the duration. Both columns should be user specific columns. You do not need to collect and save the values from each user, but you MUST point the Start Time and Duration settings, in the component settings, to columns that will hold those values. Otherwise, the stopwatch will not work correctly.

I just received my 830 and I really like it. There is, however, one functionality that i am missing. I do a lot of interval training but I cannot find a stopwatch functionality anywhere. I know that I can create training plans, but in this case I am in a training group where I only learn the training a minute before it starts, so not really an option.

It's even easier if you use the Garmin remote as you then only have to press the lap button with a finger or thumb rather than the button on the Garmin which means letting go of the bars to do it with one hand which is not good at the start of a sprint interval etc.

JordJansen, I have the same feelings about missing stop watch. I think it should be mandatory in sport device. Even outdoorsy Oregon has it. Stop watch is implemented there in very nice way: you can have it as part of screen (still seeing other parameters) or full screen app with many stop watch sections. I really miss this in Edge 830.

I was looking in Connect IQ for anything similar. In most cases I found really simple stopwatches, nothing comparable to the one from Oregon. Please let me know if you find something good there. Here is photo showing Oregon 700:

But, if your doing a "pyramid" of a set of steps, say 10 to 20 steps ie each step 2 minutes, then it's ideal for that, but once again once again if you have a rest, then it will keep logging 2 minute laps, but, if your rest period is say 10 minutes, then it's still workable as your rest period would just log it as 5 laps.

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