Friday, December 2, 2016

Performance and Memory tips

Two things play a very significant role in any application development, and those are application’s footprint and performance. Whenever I’m asked to work on these two tracks, I used to visit a huge list of sites to get many more ideas apart from what I already know. So, I thought, why can’t I collate all the good points and add them to my repository. At the same time, I thought of sharing those points in this blog.

Rather than making this blog post full of theory, I’m planning to make it simple by just adding the bullet points.

Uhh! Enough of gossip. Let’s get started by going through some common and important rules.
  • Create object only when it is really required
  • More the objects lesser the performance :( 
  • Grab resources, use them and release at the earliest
  • Default capacity of StringBuilder is 16. So, if you want to store less than 16 values then make sure to set the capacity.
  • Avoid unnecessary boxing and unboxing
  • Prefer lazy loading
  • Use Static variables cautiously as they will stay live throughout application life
  • Avoid using IDisposable everywhere
  • For web apps, enable server GC
  • Throw fever exceptions. Avoid using exceptions to control the program flow. Never catch exceptions that you can not handle. Use Performance Monitor to check exception count and other relevant information
  • Always implement Finally block
  • Prefer value types i.e. If structure can work then why to take class
  • Prefer AddRange() over Add() for adding multiple items to collection
  • Trim your working set. Use and load minimal and only required number of assemblies. Prefer single huge assembly rather than using multiple small assemblies
  • Prefer thread pool rather than creating a new thread for each request
  • Use For loop for string iterations rather than ForEach iterator
  • Use StringBuilder for string manipulation
  • Prefer early binding
  • Be careful while choosing .NET collections as each collection is designed for specific purpose
  • Use StringCollection class to store strings
  • Use Hashtable when frequent query is required on large number of records
  • Prefer ListDictionary as it is faster than HashTable for <10 records
  • For small data go for SortedList. For large data, go for ArrayList and then call Sort method on it.
  • Prefer arrays over collections unless you need some special functionality as they use contiguous memory arrangement and are faster
  • Avoid calling GC.Collect method because it traverse all the generations. If you have to call GC.Collect in your particular niche case, then make sure to clean finalized object also using GC.WaitForPendingFinalizers() and again call GC.Collect. This will collect all the dead objects.
  • Avoid implementing Finalize as it requires 2 GC cycle. Implement it only and only you hold unmanaged resources
  • Call GC.SuppressFinalize method inside Dispose method
  • Be cautious while using Thread.Suspend, as it may lead to deadlock due to incorrect synchronization.
  • Lock(object) is the cheapest method to perform synchronization
  • Avoid locking ‘this’ as it will lock entire object, even few of its member doesn’t require synchronization 
  • Prefer Using statement to ensure Dispose is called 
  • A very good diagram is given on MSDN which talks about few more concepts around this area: 





















Hope you enjoyed reading this article. Please drop your valuable comments, so that I can improvise this list further. Happy learning !!!


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