1.
Performance is a Feature!

2.
Performance is a Feature!
Matt Warren
ca.com/apm
mattwarren.github.io
@matthewwarren

3.
Front-end
Database & Caching
CLR/JVM
Mechanical
Sympathy

4.
Why does performance matter?
What do we need to measure?
How we can fix the issues?

5.
Why?
Save money
Save power
Bad perf == broken
Lost customers
Half a second delay caused
a 20% drop in traffic
(Google)

6.
Why?
http://engineroom.ft.com/2016/04/04/a-faster-ft-com/

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.
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.
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.
Never give up your
performance accidentally
Rico Mariani,
Performance Architect @
Microsoft

11.
What?
Averages
are bad

12.
"most people have
more than the average
number of legs"
- Hans Rosling

13.
https://blogs.msdn.microsoft.com/bharry/2016/03/28/introducing-application-analytics/
Application Insights Analytics

14.
When?
In production
You won't see ANY perf issues
during unit tests
You won't see ALL perf issues
in Development

15.
How?
Measure, measure, measure
1. Identify bottlenecks
2. Verify the optimisation works

16.
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.”

17.
How?
https://github.com/opserver/Opserver

18.
How?
https://github.com/opserver/Opserver

19.
How?
Micro-benchmarks

20.
How?
Profiling -> Micro-benchmarks

21.
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>();
}
http://github.com/PerfDotNet/BenchmarkDotNet

22.
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)

23.
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 |

24.
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 |

25.
How?
Garbage Collection (GC)
Allocations are cheap, but cleaning up isn’t
Difficult to measure the impact of GC

26.
https://samsaffron.com/archive/2011/10/28/in-managed-code-we-trust-our-
recent-battles-with-the-net-garbage-collector

27.
Stack Overflow Performance Lessons
Use static classes
Don’t be afraid to write your own tools
Dapper, Jil, MiniProfiler,
Intimately know your platform - CLR

28.
Roslyn Performance Lessons 1
public class Logger
{
public static void WriteLine(string s) { /*...*/ }
}
public class Example
{
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

29.
Roslyn Performance Lessons 1
public class Logger
{
public static void WriteLine(string s) { /*...*/ }
}
public class Example
{
public void Log(int id, int size)
{
var s = string.Format("{0}:{1}",
id.ToString(), size.ToString());
Logger.WriteLine(s);
}
}
AVOID BOXING
Know what’s going on under the hood

30.
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);
}
}

31.
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
High level abstractions have a cost

32.
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 |

33.
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();
}
}

34.
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

35.
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;
}
Reduce unnecessarily allocations

36.
Questions?
@matthewwarren
mattwarren.github.io