net performance by bijoy singhal
TRANSCRIPT
.Net Performance – Tips and Techniques
Bijoy SinghalDeveloper Evangelist
Microsoft [email protected]
Key Take Aways…
• Understanding reasons behind common issues that a .NET developer faces day to day
• How to leverage the tools in .NET framework to solve day to day issues…
• Performance: What and How…
• MOST IMPORTANT: The POWER of .NET framework…
.NET Tools…the hidden gems
• FusLogVW.exe – Fusion Log Viewer• NGEN.exe – Native Image Generator• ILAsm.exe, ILDAsm.exe – IL Assembler and
Dis-assembler• MDA – Managed Debugging Assistants • SoS.dll -
Perfmon: What is it?
• The name says it all.• Used to monitor the performance parameters
of the system and the user applications.• How to use it?• What are the parameters that we can track?
A few .NET Performance Counters
• .NET CLR Memory Counters• .NET CLR Exceptions• .NET CLR Loading• .NET CLR JIT• Processor• Memory
Scenario I: Application Consuming lot of memory
• What should I look at?– Memory counters list
• Indicators: Memory Leak?– # bytes in all Heaps increasing – Gen 2 Heap Size increasing – # GC handles increasing – # total committed/Reserved Bytes increasing– % Time in GC
• Indicators: Memory Fragmentation?– # total reserved Bytes significantly larger than # total committed Bytes – # of Pinned Objects increasing – # GC handles increasing – # bytes in all heaps always increasing.
Scenario II: Application throwing lot of exceptions unnecessarily…
• Cost of throwing an exception• What else can go wrong?– Blocking exception handlers– Loss of exception context
• Perfmon Exception counters to look at:– # of Exceps Thrown – # of Exceps Thrown / Sec – # of Filters / Sec – Throw to Catch Depth / Sec
Scenario III: Application Takes too long to Load
• Possible Reasons:– Too many assemblies to load– Too much of jitting happening.
• Perfmon counters to look at:– % Time in Loading– Current Assemblies– Rate of Assemblies/AppDomains– # of IL Bytes JITted – # of methods JITed– % time in JIT
A Quick note on ASP.NET specific counters
• Two types:– System Counters– Application Counters
• Few important Counters:– ASP.NET/Application Restarts.– ASP.NET/Requests Queued– ASP.NET Application/Requests/sec– ASP.NET Application/Errors Total– AND many more…
.NET Application Performance
• Performance is a relative term:– What is good for you may not be good for others.
• Performance Bottlenecks in .NET:– Am I loading too many assemblies at the start?– Am I doing too many memory operations? Am I
trying to deal with the memory management on my own?
– Am I misusing Exceptions and defeating their purpose?
– The list is long…
.NET Application Performance
• Way outs:– Add trace messages in your application.– Debug it.– Use Debugging tools to do post mortem analysis.– Use Perfmon.
Scenario I: FileNotFoundException
• “Our application ran successfully on the Development machine but it is failing with FileNotFoundException when we deploy it in production”
• Fusion – How the CLR locates assemblies.• How can the fusion log viewer help us here• How to look into the Fusion Log• Fusion Log Viewer: Fuslogvw.exe• Demo
Scenario II: Slow To Load
• “Our application takes too long to load for the first time. It exhibits the same behavior once in a while…”
• What happens when a .NET application runs for the first time
• Native Images and how they speed up the loading process
• NGEN: Native image generation• How NGEN will help us here• Demo
Scenario III: Memory Leak
• “ My application is consuming lot of memory. It looks like a ‘Memory Leak’ to me…”
• .NET Memory Manager: GC• How to get managed heap information• How the CLRProfiler can help us here• Demo
Scenario IV: PInvoke Issues
• “ I used PInvoke to call a native API, I’m doing everything correct, but the call is failing/ the application is failing with AccessViolationException…”
• Crucial to match the native API signature exactly without any exception
• What is MDA• How MDA will help us here• Demo
