The Need for (Build) Speed

Transcription

1 The Need for (Build) Speed Lasse Koskela (Please go ahead and pre-fill those feedback forms. I appreciate that. It also brings you that much closer to beer.)

2 Lasse Koskela works as a coach, trainer, consultant and programmer, spending his days helping clients and colleagues at Reaktor create successful software products. Follow him on Twitter

3 Session Outline 1) Impact of build time 2) Profiling a build 3) Optimizing test code Standing between an audience and their beer is tough so you better talk fast. ~ agile conference proverb 4) Tweaking infrastructure

4 Impact of build time

5 Delayed feedback is bad for you The faster you know that your software is (still) working as it should the faster your brain can move on to the next thing. The longer you have to wait for feedback the higher the chance of doing rework and context-switching.

6 Delayed feedback costs $$$ [Google] estimated that a bug found during TDD costs $5 to fix, which surges to $50 for tests during a full build and $500 during an integration test. It goes to $5000 during a system test. Fixing bugs earlier would save them an estimated $160M per year.

7 Profiling a build

8 How do we know what s up? Shooting in the dark works amazingly well...if you re lucky. The rest of us need to understand what is making our build slow before reaching for our guns.

9 What exactly do we want to know? How much time it takes altogether? Which build activities take up the majority of that total? Which of these have potential for optimization?

10 Demo Profiling an Apache Ant build with built-in utilities and open source tools

11 Demo Profiling an Apache Ant build with built-in utilities and open source tools $ ant -listener net.sf.antcontrib.perf.antperformancelistener

12 Demo Profiling an Apache Ant build with built-in utilities and open source tools $ ant -listener net.sf.antcontrib.perf.antperformancelistener $ ant -logger org.apache.tools.ant.listener.profilelogger

13 Demo Profiling an Apache Maven build with built-in utilities and open source tools

14 Demo Profiling an Apache Maven build with built-in utilities and open source tools <build> <extensions> <extension> <groupid>com.github.lkoskela</groupid> <artifactid>maven-build-utils</artifactid> <version>1.4</version> </extension> </extensions> </build>

15 Optimizing test code

16 Tests can be slow because they...

17 Tests can be slow because they... a) do many things.

18 Tests can be slow because they... a) b) do many things. do slow things.

19

20 Examples of doing too much

21 Examples of doing too much Tests do setup that isn t relevant to the test.

22 Examples of doing too much Tests do setup that isn t relevant to the test. Tests build input from unnecessarily raw materials.

23 Examples of doing too much Tests do setup that isn t relevant to the test. Tests build input from unnecessarily raw materials. Tests do the same thing many times when once is enough.

24 Examples of doing too much Tests do setup that isn t relevant to the test. Tests build input from unnecessarily raw materials. Tests do the same thing many times when once is enough. Tests use a slow real object when a stub would suffice.

25 Examples of doing too much Examples of slow things Tests do setup that isn t relevant to the test. Tests build input from unnecessarily raw materials. Tests do the same thing many times when once is enough. Tests use a slow real object when a stub would suffice.

26 Examples of doing too much Tests do setup that isn t relevant to the test. Examples of slow things Tests invoke Thread.sleep(...) to wait for task completion. Tests build input from unnecessarily raw materials. Tests do the same thing many times when once is enough. Tests use a slow real object when a stub would suffice.

27 Examples of doing too much Tests do setup that isn t relevant to the test. Tests build input from unnecessarily raw materials. Examples of slow things Tests invoke Thread.sleep(...) to wait for task completion. Components talk to each other over a network protocol. Tests do the same thing many times when once is enough. Tests use a slow real object when a stub would suffice.

28 Examples of doing too much Tests do setup that isn t relevant to the test. Tests build input from unnecessarily raw materials. Tests do the same thing many times when once is enough. Examples of slow things Tests invoke Thread.sleep(...) to wait for task completion. Components talk to each other over a network protocol. Tests run against a production-like database. Tests use a slow real object when a stub would suffice.

29 Examples of doing too much Tests do setup that isn t relevant to the test. Tests build input from unnecessarily raw materials. Tests do the same thing many times when once is enough. Tests use a slow real object when a stub would suffice. Examples of slow things Tests invoke Thread.sleep(...) to wait for task completion. Components talk to each other over a network protocol. Tests run against a production-like database. Tests access a file system.

30 Demo An example of irrelevant setup that s inherited through a hierarchy of abstract test classes.

31 Demo An example of tests wasting valuable time by Thread#sleep ing too much.

32 Demo An example of a test that uses a slow(ish) real implementation that talks to the network stack.

33 Tweaking infrastructure

34 Is your build s bottleneck... CPU I/O

35

36 Peaking user time suggests CPU running hot

37

38 Peaking idle time suggests CPU is waiting

39

40 Peaking system calls suggests lots of I/O

41 Lifting the CPU bottleneck by using more hardware

42 Lifting the CPU bottleneck by using more hardware

43 Demo An example of a Maven build that employs multiple CPU cores.

44 Lifting the CPU bottleneck by using better hardware

45 Lifting the CPU bottleneck by using better hardware

46 Lifting the CPU bottleneck by using better hardware Amazon EC2 Small Instance 1.7 GB memory 1 virtual core with 1 EC2 compute units Amazon EC2 Medium Instance 3.75 GB memory 1 virtual core with 2 EC2 compute units

47 Demo An example of a Maven build that is run in the cloud on a (more or less) powerful computer.

48 Lifting the I/O bottleneck by using better hardware

49 Lifting the I/O bottleneck by using better hardware

50 Demo An example of a build that is run from a (more or less) fast disk.

51 Lifting the I/O bottleneck by using more hardware

52 Lifting the I/O bottleneck by using more hardware

53 Summary

54 Please, fill the feedback form for me. I d really appreciate that. TITLE: The Need for (Build) Speed PRESENTER: Lasse Koskela