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Performance is a Feature!

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Starting with the premise that "Performance is a Feature", Matt Warren will show you how to measure, what to measure and how to get the best performance from your .NET code.

We will look at real-world examples from the Roslyn code-base and StackOverflow (the product), including how the .NET Garbage Collector needs to be tamed!

The presentation covers:
Why we should care about performance
Pitfalls to avoid when measuring performance
How the .NET Garbage Collector can hurt performance
Real-world performance lessons from open-source code

The webinar recording can be found here: http://www.postsharp.net/blog/post/webinar-recording-performance-is-a-feature

Published in: Software
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Performance is a Feature!

  1. 1. Performance is a Feature!
  2. 2. Performance is a Feature! Matt Warren ca.com/apm www.mattwarren.org @matthewwarren
  3. 3. Watch the webinar recording here: http://www.postsharp.net/blog/pos t/webinar-recording-performance- is-a-feature
  4. 4. Front-end Database & Caching .NET CLR Mechanical Sympathy
  5. 5. Why does performance matter? What do we need to measure? How we can fix the issues?
  6. 6. Why? Save money Save power Bad perf == broken Lost customers Half a second delay caused a 20% drop in traffic (Google)
  7. 7. Why? “The most amazing achievement of the computer software industry is its continuing cancellation of the steady and staggering gains made by the computer hardware industry.” - Henry Petroski
  8. 8. Why? “We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%.“ - Donald Knuth
  9. 9. Why? “We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%.“ - Donald Knuth
  10. 10. Never give up your performance accidentally Rico Mariani, Performance Architect @ Microsoft
  11. 11. What? Averages are bad
  12. 12. "most people have more than the average number of legs" - Hans Rosling
  13. 13. https://www.ted.com/talks/hans_rosling_shows_the_best_stats_you_ve_ever_seen
  14. 14. https://blogs.msdn.microsoft.com/bharry/2016/03/28/introducing-application-analytics/ Application Insights Analytics
  15. 15. Watch the webinar recording here: http://www.postsharp.net/blog/pos t/webinar-recording-performance- is-a-feature
  16. 16. When? In production You won't see ANY perf issues during unit tests You won't see ALL perf issues in Development
  17. 17. How? Measure, measure, measure 1. Identify bottlenecks 2. Verify the optimisation works
  18. 18. How? “The simple act of putting a render time in the upper right hand corner of every page we serve forced us to fix all our performance regressions and omissions.”
  19. 19. How? https://github.com/opserver/Opserver
  20. 20. How? https://github.com/opserver/Opserver
  21. 21. How? Micro-benchmarks
  22. 22. How? Profiling -> Micro-benchmarks
  23. 23. http://www.hanselman.com/blog/BenchmarkingNETCode.aspx
  24. 24. using BenchmarkDotNet.Attributes; using BenchmarkDotNet.Running; static Uri @object = new Uri("http://google.com/search"); [Benchmark(Baseline = true)] public string RegularPropertyCall() { return @object.Host; } [Benchmark] public object Reflection() { Type @class = @object.GetType(); PropertyInfo property = @class.GetProperty(propertyName, bindingFlags); return property.GetValue(@object); } static void Main(string[] args) { var summary = BenchmarkRunner.Run<Program>(); }
  25. 25. Watch the webinar recording here: http://www.postsharp.net/blog/pos t/webinar-recording-performance- is-a-feature
  26. 26. Compared to one second • Millisecond – ms –thousandth (0.001 or 1/1000) • Microsecond - μs –millionth (0.000001 or 1/1,000,000) • Nanosecond - ns –billionth (0.000000001 or 1/1,000,000,000)
  27. 27. BenchmarkDotNet BenchmarkDotNet=v0.9.4.0 OS=Microsoft Windows NT 6.1.7601 Service Pack 1 Processor=Intel(R) Core(TM) i7-4800MQ CPU @ 2.70GHz, ProcessorCount=8 HostCLR=MS.NET 4.0.30319.42000, Arch=32-bit RELEASE JitModules=clrjit-v4.6.100.0 Type=Program Mode=Throughput Method | Median | StdDev | Scaled | --------------------- |------------ |----------- |------- | RegularPropertyCall | Reflection |
  28. 28. BenchmarkDotNet BenchmarkDotNet=v0.9.4.0 OS=Microsoft Windows NT 6.1.7601 Service Pack 1 Processor=Intel(R) Core(TM) i7-4800MQ CPU @ 2.70GHz, ProcessorCount=8 HostCLR=MS.NET 4.0.30319.42000, Arch=32-bit RELEASE JitModules=clrjit-v4.6.100.0 Type=Program Mode=Throughput Method | Median | StdDev | Scaled | --------------------- |------------ |----------- |------- | RegularPropertyCall | 13.4053 ns | 1.5826 ns | 1.00 | Reflection | 232.7240 ns | 32.0018 ns | 17.36 |
  29. 29. [Params(1, 2, 3, 4, 5, 10, 100, 1000)] public int Loops; [Benchmark] public string StringConcat() { string result = string.Empty; for (int i = 0; i < Loops; ++i) result = string.Concat(result, i.ToString()); return result; } [Benchmark] public string StringBuilder() { StringBuilder sb = new StringBuilder(string.Empty); for (int i = 0; i < Loops; ++i) sb.Append(i.ToString()); return sb.ToString(); } https://github.com/dotnet/roslyn/issues/5388
  30. 30. How? Garbage Collection (GC) Allocations are cheap, but cleaning up isn’t Difficult to measure the impact of GC
  31. 31. https://samsaffron.com/archive/2011/10/28/in-managed-code-we-trust-our- recent-battles-with-the-net-garbage-collector
  32. 32. Stack Overflow Performance Lessons Use static classes Don’t be afraid to write your own tools Dapper, Jil, MiniProfiler, Intimately know your platform - CLR
  33. 33. Roslyn Performance Lessons 1 public class Logger { public static void WriteLine(string s) { /*...*/ } } public class Logger { public void Log(int id, int size) { var s = string.Format("{0}:{1}", id, size); Logger.WriteLine(s); } } Essential Truths Everyone Should Know about Performance in a Large Managed Codebase http://channel9.msdn.com/Events/TechEd/NorthAmerica/2013/DEV-B333
  34. 34. Roslyn Performance Lessons 1 public class Logger { public static void WriteLine(string s) { /*...*/ } } public class BoxingExample { public void Log(int id, int size) { var s = string.Format("{0}:{1}", id.ToString(), size.ToString()); Logger.WriteLine(s); } } https://github.com/dotnet/roslyn/pull/415 AVOID BOXING
  35. 35. Roslyn Performance Lessons 2 class Symbol { public string Name { get; private set; } /*...*/ } class Compiler { private List<Symbol> symbols; public Symbol FindMatchingSymbol(string name) { return symbols.FirstOrDefault(s => s.Name == name); } }
  36. 36. Roslyn Performance Lessons 2 class Symbol { public string Name { get; private set; } /*...*/ } class Compiler { private List<Symbol> symbols; public Symbol FindMatchingSymbol(string name) { foreach (Symbol s in symbols) { if (s.Name == name) return s; } return null; } } DON’T USE LINQ
  37. 37. BenchmarkDotNet BenchmarkDotNet=v0.9.4.0 OS=Microsoft Windows NT 6.1.7601 Service Pack 1 Processor=Intel(R) Core(TM) i7-4800MQ CPU @ 2.70GHz, ProcessorCount=8 Frequency=2630654 ticks, Resolution=380.1336 ns, Timer=TSC HostCLR=MS.NET 4.0.30319.42000, Arch=32-bit RELEASE JitModules=clrjit-v4.6.100.0 Type=Program Mode=Throughput Runtime=Clr Method | Median | StdDev | Gen 0 | Bytes Allocated/Op | ---------- |----------- |---------- |------- |------------------- | Iterative | 39.0957 ns | 0.2150 ns | - | 0.00 | LINQ | 53.2441 ns | 0.5385 ns | 701.50 | 23.21 |
  38. 38. Roslyn Performance Lessons 3 public class Example { // Constructs a name like "Foo<T1, T2, T3>" public string GenerateFullTypeName(string name, int arity) { StringBuilder sb = new StringBuilder(); sb.Append(name); if (arity != 0) { sb.Append("<"); for (int i = 1; i < arity; i++) { sb.Append('T'); sb.Append(i.ToString()); } sb.Append('T'); sb.Append(arity.ToString()); } return sb.ToString(); } }
  39. 39. Roslyn Performance Lessons 3 public class Example { // Constructs a name like "Foo<T1, T2, T3>" public string GenerateFullTypeName(string name, int arity) { StringBuilder sb = new AcquireBuilder(); sb.Append(name); if (arity != 0) { sb.Append("<"); for (int i = 1; i < arity; i++) { sb.Append('T'); sb.Append(i.ToString()); } sb.Append('T'); sb.Append(arity.ToString()); } return GetStringAndReleaseBuilder(sb); } } OBJECT POOLING
  40. 40. Roslyn Performance Lessons 3 [ThreadStatic] private static StringBuilder cachedStringBuilder; private static StringBuilder AcquireBuilder() { StringBuilder result = cachedStringBuilder; if (result == null) { return new StringBuilder(); } result.Clear(); cachedStringBuilder = null; return result; } private static string GetStringAndReleaseBuilder(StringBuilder sb) { string result = sb.ToString(); cachedStringBuilder = sb; return result; }
  41. 41. Questions? @matthewwarren www.mattwarren.org
  42. 42. Watch the webinar recording here: http://www.postsharp.net/blog/pos t/webinar-recording-performance- is-a-feature

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