Skip to main content

Ce nu trebuie sa facem cand vrem sa masuram viteza de executie a unei zone de cod

Cand testam viteza de executie a unui aplicatii sau a unei parti din cod nu trebuie sa uitam:
Sa masuram doar codul care trebuie masurat
Cand trebuie sa verificam viteza de execuție a unei porțiuni din cod, trebuie sa încercam sa eliminam cat mai mult cu putința liniile de cod care nu ne interesează si care nu trebuie masurate.
De exemplu in codul de mai jos se doreste cronometrarea doar in zona in care se procesează datele, fara timpul necesar citirii datelor si inițializarea altor obiecte.
public void DoTest()
{
//Start monitorizare.

var items=ReadData();
var container=new Container();
container.Init();

//Proceseaza datele.
...

Save(items);

//Stop monitorizare
}
Corect ar fi:
public void DoTest()
{
var items=ReadData();
var container=new Container();
container.Init();

//Start monitorizare.
//Proceseaza datele.
//Stop monitorizare

Save(items);
}
Dezactivati mesajele de debug
Toate mesajele de genul Debug.Writeline("..."), Trace("..."), Logger.WriteLine("...") trebuie dezactivate. Acestea consuma resurse si timp, iar un functie de accesul la disk, ele pot sa afecteze timpii finali, a.i. sa se obtina timpi foarte diferiti la mai multe rulari.
Nu faceti testele de viteza in Debug
Cand testati in Debug, pe langa codul propriu-zis apar nenumarate simboluri de debug si calluri care interactioneaza cu debugul. De foarte multe ori codul compilat in release, ruleaza de zeci de ori mai rapid.
Nu folositi DateTime.Now
Pentru a calcula durata de executie nu este recomanda sa folositi DateTime.Now. Daca de exemplul threadul este suspendat de OS, pot sa apara intarzieri care sa afecteze timpul final. Pentru a masura durata de executie se poate folosi Stopwatch. Aceasta are metoda Start(), Stop() pentru controlul cronometrului. Pentru a obtine durata putem sa apelam propietatile Elapsed, ElapsedMilliseconds sau ElapsedTicks. Daca dorim sa verificam daca cronometrul ruleaza putem sa ne folosim de propietate IsRunning.
public void DoTest()
{
var items=ReadData();
var container=new Container();
container.Init();

Stopwatch stopwatch=new Stopwatch();
stopwatch.Start();
//Proceseaza datele.
stopwatch.Stop()

Console.WriteLine(string.Format("Durata: {0}",stopwatch.Elapsed);

Save(items);
}
Masurati de mai multe ori si calculati valoarea medie a timpilor de executie
Deoarece pe acelasi procesor ruleaza mai multe procese de la SO la antivirus, timpii pe care ii obtinem pot sa difere. Este recomandat sa se ruleze un test de cel putin 1000 de ori daca este posibil si sa se calculeze media aritmetica. Datele obtinute se pot salva, iar la sfarsit informatia se poate prelucra.
static void CalculareTimpMediu()
{
var items = ReadData();

var watch = new Stopwatch();
var cycles = Math.Pow(10, 3);
var times = 0D;

for (var i = 0; i < cycles; i++)
{
watch.Reset();
watch.Start();

//Proceseaza datele.

watch.Stop();
times += watch.ElapsedMilliseconds;
}

inputList.Clear();
Console.WriteLine("Durata: " + (times / cycles));
}
Exista nenumarate aplicatii care ne pot ajuta sa masuram viteza de executie. Dar pentru o testare simpla, putem sa face totul manual. Putem sa ne cream o librărie simpla care sa ne ajute. Timpii intermediari obtinuti e bine sa ii salvati in memorie si doar la sfarsit pe disk. In cazul in care stocati timpii sau alte date pentru testare in siruri, este bine sa alocati de la bun inceput spatiul necesar pentru acestea.

Comments

Popular posts from this blog

How to check in AngularJS if a service was register or not

There are cases when you need to check in a service or a controller was register in AngularJS.
For example a valid use case is when you have the same implementation running on multiple application. In this case, you may want to intercept the HTTP provider and add a custom step there. This step don’t needs to run on all the application, only in the one where the service exist and register.
A solution for this case would be to have a flag in the configuration that specify this. In the core you would have an IF that would check the value of this flag.
Another solution is to check if a specific service was register in AngularJS or not. If the service was register that you would execute your own logic.
To check if a service was register or not in AngularJS container you need to call the ‘has’ method of ‘inhector’. It will return TRUE if the service was register.
if ($injector.has('httpInterceptorService')) { $httpProvider.interceptors.push('httpInterceptorService&#…

ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded

Today blog post will be started with the following error when running DB tests on the CI machine:
threw exception: System.InvalidOperationException: The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information. at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName) This error happened only on the Continuous Integration machine. On the devs machines, everything has fine. The classic problem – on my machine it’s working. The CI has the following configuration:

TeamCity.NET 4.51EF 6.0.2VS2013
It seems that there …

Run native .NET application in Docker (.NET Framework 4.6.2)

Scope
The main scope of this post is to see how we can run a legacy application written in .NET Framework in Docker.

Context
First of all, let’s define what is a legacy application in our context. By a legacy application we understand an application that runs .NET Framework 3.5 or higher in a production environment where we don’t have any more the people or documentation that would help us to understand what is happening behind the scene.
In this scenarios, you might want to migrate the current solution from a standard environment to Docker. There are many advantages for such a migration, like:

Continuous DeploymentTestingIsolationSecurity at container levelVersioning ControlEnvironment Standardization
Until now, we didn’t had the possibility to run a .NET application in Docker. With .NET Core, there was support for .NET Core in Docker, but migration from a full .NET framework to .NET Core can be costly and even impossible. Not only because of lack of features, but also because once you…