How to profile? - profiler

I've developed a little screenshot application but I've heard that I should profile my code to see where it's using a lot of resources and stuff.
What is a profiler? what does it do? Where can i get it for free? and How do I use it?

A profiler is a software tool which intercepts and measures every executed code path in a certain run of an application. They store this information and later report graphically (or tabularly) where does your code spend most of the running time so you can optimize where it really matters.
About where to get one, it depends on your platform/language combination.

What language are you developing in? For C#, check this question.
Any decent C# profilers out there?
Here's one for C++
Decent profiler for Windows?
In fact, check the profiler tag to see all the questions tagged in connection with profilers.
https://stackoverflow.com/questions/tagged/profiler

See:
what-techniques-can-you-use-to-profile-your-code
You didn't say what language you use. For C/C++ (and probably others) a free ones are:
gcov
gprof

Related

Updating a VB6 application to .net

I know a lot of questions have been asked about VB6 migration (and I've read most of them), but I'm still not entirely certain on what the best way to go about this is.
We have a client that we built an order tracking application for about a decade back and they came to us this week saying they were having some issues with it. The app was written entirely in VB6, which has been something of a hassle as tracking down the necessary tools to work with a project so old took some considerable effort. In an effort to make any future maintenance less of a headache, my boss wants to pitch the idea to them of updating the app to .net and wants to know what exactly that would entail. I've never done anything like this before, but what I've read (both here and elsewhere) suggests that Microsoft's "auto-update" from VB6 to .net simply doesn't work very well and I'd pretty much have to rebuild the app from the ground up.
To get to the crux of my question: is this the case? Would I pretty much just need to rewrite it, or is there another means of going about this that could/would save me a lot of time/effort?
Any insight would be greatly appreciated.
VB6 and VB.NET are radically different. The syntax has changed, and so has the underlying structures, forms, custom controls, and almost every single aspect you can possibly think about.
A complete redesign and reassessment of needs and functionality is imperative. With .NET the plethora of new libraries and features supersede the antiquated VB6 libraries, OCXs, etc. Also if you feel bold, you can migrate your code to C# and other CIL languages aside from VB.
Out of hand, the Microsoft migration tool will not do much. Moreover, it also depends on whether you have your business logic well separated from your GUI. Otherwise, it will make it even harder. Depending on the size of your application, it might make it quite expensive. Another possible solution you might consider is to run your app in a virtual environment or on a remote app http://technet.microsoft.com/en-us/library/cc730673(v=ws.10).aspx that will ease the deployment pain.
I have also researched this topic.
Try the smart rewrite solution that converts 95% of the code automatically.
first, run your app through the assessment wizard to determine estimated costs and resources needed.
http://visualwebgui.com/Gizmox/Solutions/InstantbCloudmoveb/tabid/744/Default.aspx

Benchmark Tools For Delphi

I'm looking for some tools to improve my Delphi development.
And a tool that I could not found any free project is a benchmark tool.
Some one have some hit about some project to use ?
Today to check where I must focus my optimizations I use sample profiling, but it's not enough
I must file the function that spent more time overage, not just the top called functions.
Tks
I think the acknowledged leader in this field is AQtime.
If you have no money then you can try Sampling Profiler.
I'm sure others will be along in due course to offer yet more suggestions!
Check out my question on Profiler and Memory Analysis Tools for Delphi. In my Addenum 4, I mention André's Open Source Profiler for Delphi called AsmProfiler that he made. See his answer to that question that led me to it.
I had downloaded it and tried it and it is quite good. It is an instrumenting profiler like AQTime, so it may be better than a Sampling Profiler for certain optimizations. It does procedure-based timings, so the one thing it can't do that AQTime is line-by-line based timings. But for a free program that works well, most often procedure-based timings are good enough. I had used GpProfile very productively for many years which was very similar but it is no longer available for current versions of Delphi.

Encoding Ruby on Rails code?

Are there any applications out there that will let me encode my Ruby on Rails code so others can't read it? I plan on selling a few small applications, but I really don't want everyone knowing my code.
Thanks.
Only example I have seen in the wild is Mingle from ThoughtWorks, which runs on JRuby, which I think they must have modified in some way to run the encrypted code.
http://www.thoughtworks-studios.com/mingle-agile-project-management
I think they may have used something like this AOT compiler:
http://kenai.com/projects/jruby/pages/RailsAOT
This also looks promising:
http://www.infoq.com/news/2008/10/rubyencoder
Check out this answer for other ideas.
Can you Distribute a Ruby on Rails Application without Source?
If you want people to able to run your code (and if you don't, then why did you write it in the first place?), then their CPU needs to be able to execute your code. In order to be able to execute the code, the CPU needs to be able to understand it.
Since CPUs are dumb, and humans aren't, this means that humans can understand the code as well.
The only way you can protect your code through technical means, is if you "own" the entire execution path: you need to build your own CPU, your own computer, write your own operating system and your own Ruby interpreter. Then, and only then can you protect your code. (But note that even the tiniest mistake will render all of your protections useless. Microsoft, Apple, Sony, the Music Industry and the Movie Industry can attest to that.)
Or, you could just do nothing, which means that your code will be automatically protected by copyright law.
Thanks for all your answers! Currently I'm looking at jRuby and Ruby Encoder options but if I find neither are what I want then I think I should just sell the code and focus more on getting customers. It really doesn't make sense to spend all this time and money on an encryption that can be easily cracked anyways.
Maybe you could host the application yourself.
This way nobody will have ever access to your code and you're clients will use the application everywhere via Internet and also will pay you for the support.
In order to host rails application the easiest way you could try http://heroku.com/ or even set a small VPS with apache and mod_passenger.
No, there is no way to have executable code that can't be read. Hard to read yes, impossible to read is... impossible. Best you can do is obfuscate, of which there are many examples around the net (but I don't know of any libraries that do it for you).

How can I test if my web application could handle heavy traffic?

What would be a proper way to simulate a large number of requests to test if my web application can handle it?
You could try using Microsoft's WCAT tools. Look here: http://support.microsoft.com/kb/231282
They're free, too. That's always nice.
Depending on your budget, you may be interested in some load testing software designed for this. A Google search brings up all sorts of alternatives. This is probably the best way to do it.
This one has a free trial version and isn't too pricey, but I would recommend shopping around first.
I've used JMeter in the past, and I find it to be very useful for stress/load testing as website, even ones written in ASP.NET (with or without MVC).
In general you would want to (with any tool) write a script of what an average user of your site would do. You may even end up creating multiple of these scripts. Tools like JMeter even allow for a random element to be added to a script. With these scripts created a load testing tool can then simulate as many users as you desire hitting your site.
I would recommend allow JMeter to slowly ramp up the number of concurrent users and watch the response time graph. At the point where the response time starts increasing too highly is at the point where you've hit the maximum number of users (given you scripts) that your site can handle.
ab and httperf are two, more unixy options, if you don't mind delving in that direction.
There's a nice screencast for using httperf by peepcode.
Use the load testing tools from Visual Studio Team System. 2010 if you can get it.
The tools are great to use and provide wonderful instrumentation. There is also a programming model to go with the tools, allowing you to make some very complex testing scenarios possible.
Post the URL on stackoverflow.
Make it sound like a challenge, so lots of people come check it out: "Can you find the hidden performance problem in this app?"

Which is the programming language to retrieve info. such as OS info, memory, processes/threads, program version, DLL version etc?

I want to develop an application that can retrieve information such as, DLL version, DLL build mode(debug or release), info. regarding OS, memory, processer, processes/threads, program version etc. I am developing this mainly for Windows, but it'd be good if the application supports Linux too(wherever applicable).
I am basically a java programmer, and I know C, C++ to some extent.
Which programming language should I go for, that'd make my job easy? i.e. which language has APIs to fetch these kind of information?
Well... APIs are available regardless of the language... But the easiest way to get at what you are trying to do is going to be a C or C++ app. That doesn't mean it'll be easy (getting a DLL version is easy, getting memory and processor type is easy. The other stuff is certainly possible, but you may have to roll up your sleeves and learn the win32 API).
You might want to take a look at an application that already does exactly what you are asking about (Process Explorer) before you try to develop this yourself... It's going to be a big undertaking - and the folks at Sys Internals are really, really good at this stuff, and have already done it.
You commented on Kevin Day's answer that you would prefer to use Java for this.
Java is not very well suited for this, because the information you want to get is very platform-specific, and since Java is designed to be platform-independent, there are not a lot of ways to get at this kind of information from Java.
There are some methods in classes java.lang.System and java.lang.Runtime to get information about the platform that your Java program is running on. For example, class Runtime has a method availableProcessors() that tells you how many processors are available to the Java virtual machine. Note that this is not the same as the number of processors (or cores) that exist in the computer; the documentation even says that the number may change while the program is running.
Lookup the documentation for java.lang.System and java.lang.Runtime for more information.
Most likely you're not going to get exactly the information that you need by using pure Java - C or C++ will be better suited to get this kind of platform-specific information. If you would need this information from a Java program, you could write a small DLL or shared library and use JNI to call into it from your Java program.
Since DLLs are mentioned I presume we are talking about Windows.
I would recommend using WMI queries. They look very much like SQL and give you access to many very useful classes.
e.g. all info about the OS can be found here - in W32_OperatingSystem:
http://msdn.microsoft.com/en-us/library/aa394239(VS.85).aspx
You can use WMI classes from any language including C++.
As a side note - if you start a new application from scratch consider using PowerShell - new scripting language from Microsoft.

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