Introduction
From my experience , i have found that when carefully optimized, you can maximize your application performance up to 30%
using these .net optimization techniques. Many programmers try to write the code first and optimize later, that is a bad design
principle, learn to implement these best practices throughout the design, development and deployment cycles.
Try them and feel the difference.
1) Use Option Explicit and Option Strict
2)Donot Late Bind
Calls on Object cause late binding. Such binding requires work at runtime. The binding process in .net is more complex than in VB6. Using operators on objects can cause late binding:
eg:-
Dim o, o1, o2 As Object
o = o1 + o2 ' Late bound
3)Use the Right Types
Understand the 2 kinds of types: Value types and Reference Types. The reference types are allocated on heaps and copies do not attract a performance cost whereas the value types are allocated "in place" and copies have a performance cost.
There is no "one rule that fits all". The rule of thumb is to use value types for small objects and reference type for large objects.
4)Avoid Slow Conversions
Understand boxing and unboxing. When you assign a value type to an object a boxing operation occurs, similarly when you convert an object type to original type an unboxing occurs. Boxing and unboxing can prove as bottlenecks to application
performance. Use Option Strict On to catch such slow type conversions
5)Beware of Multidimensional Arrays and uninitialized arrays
Make sure you use ArrayList object to avoid usage of "ReDim", "Preserve" keywords. Runtime memory allocation is not recommended practice in programming world. Use array of arrays instead of multi-dimensional arrays, they are relatively quicker.
6) String Tips
Strings are now immutable in .net Framework. There are a few nibble areas you need to be careful.
When you use "&" operator actually is new string is created to produce the concatenated string. That means more memory allocation!!!. Use System.Text.StringBuilder to build long concatenated strings, it is extremely
efficient.
Word of caution do not do this. It is extremely inefficient try using replace instead
mid(str,2,4)="abcd"
If globalization isn't important: Use Option Binary instead of Text. Use ".ToString" to perform string formats instead of Format function
7) Minimize Exceptions
Use exceptions only for errors, exceptions are not events. I see many people using it to pass error messages back to calling routine. Please be aware that throwing exception is extremely expensive!!!
For VB guys use Try ...Catch instead of "On Error" statements
8) Make your calls Chunky not Chatty
Calls across your runtime boundaries are expensive. Be careful when you use Declare Statements,COM objects,AppDomains and Remoting. When you design calls ensure you minimize calls and maximize data!!!
Other Tips
Don't
--> Allocate memory when you donot need.
--> Have large number of local variables.
--> write really large methods(rule of thumb is 25 lines, more than that consider refactoring your code).
---> Use Overridable Methods Only when needed, calls to such methods are little expensive
---> Use Release Builds
---> Remove integer overflow checks if your application is not calcuation intensive
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| Author: Ravi Makwana 06 Oct 2004 | Member Level: Bronze Points : 0 |
A nice & valuable article. This will prove to be a control measure for performance of any application.
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