Starting with the premise that "Performance is a Feature", this session will look at how to measure, what to measure and how 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!
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 Peteroski
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. Never give up your
performance accidentally
Rico Mariani,
Performance Architect @
Microsoft
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.”
25. 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>();
}
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. 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 |
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();
}
36. Stack Overflow Performance Lessons
Use static classes
Don’t be afraid to write your own tools
Dapper, Jil, MiniProfiler,
Intimately know your platform - CLR
37. 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
38. 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);
}
}
AVOID BOXING
39. 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);
}
}
40. 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
42. 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();
}
}
43. 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