Meeting Tight Software Schedules Through Cycle Time Reduction

Transcription

1 Meeting Tight Software Schedules Through Cycle Time Reduction Dennis J. Frailey Retired Principal Fellow, Raytheon Company Sole Proprietor, DJF CO Copyright , Dennis J. Frailey Reducing SW Cycle Time 1

2 Outline Background - Why Cycle Time is Important Cycle Time Reduction Issues and Examples Defining Cycle Time Three Fundamental Problems Typical Causes Spotting the Symptoms and Opportunities Fixing the Problems - Five Principles A Few Lessons Learned 3 Copyright , Dennis J. Frailey Reducing SW Cycle Time 3

3 Why Cycle Time is Important I need that software no later than next week! Why is it taking so long? We ll work overtime to get it out, sir. But Yes, we re Sir! already Right working Away, overtime! Sir. 4 Copyright , Dennis J. Frailey Reducing SW Cycle Time 4

4 Definition of Cycle Time Cycle time is the time required to execute all activities in a process, including actual processing time AND all waiting time Consider a 10 minute oil change 5 Copyright , Dennis J. Frailey Reducing SW Cycle Time 5

5 Short Cycle Time Gives You a Competitive Edge You sell your software while the competitor is still completing theirs You start the next software product while the competitor is still completing the current one You lower your costs Or you can start development later in the program cycle More time to determine the requirements And, once you start, you allow less time to change requirements 6 Copyright , Dennis J. Frailey Reducing SW Cycle Time 6

6 How Can Cycle Time be Improved? The following video illustrates how to improve cycle time As you watch, think of ideas that might be applicable to software development What did they do to reduce cycle time? 7 Copyright , Dennis J. Frailey Reducing SW Cycle Time 7

7 Some Lessons from the Cycle Time Video What did they do? Is there a software counterpart? Things they did: +_%$#@& ~~~~~~~~~~ ~~~~~~~~~~~ ~~~~~~~~~~~ 8 Copyright , Dennis J. Frailey Reducing SW Cycle Time 8

8 How do You Measure Cycle Time? STATIC CYCLE TIME The average of the actual cycle times (CT) experienced by some number (n) of products Cycle Time = CT 1 + CT 2 + CT 3 + CT CT n n But this is not always easy to measure when many of the products are only partway through the process so we need a dynamic measure 9 Copyright , Dennis J. Frailey Reducing SW Cycle Time 9

9 Dynamic Cycle Time The total work in process divided by the throughput of the process Cycle Time = WIP (products being developed) THROUGHPUT (products produced/unit time) WIP = Work in Process For related background, see Gross and Harris, in reference list, p Copyright , Dennis J. Frailey Reducing SW Cycle Time 10

10 How is Cycle Time Improved? Doing every process step faster? Working longer hours? Piling up work? Faster!!! 11 Copyright , Dennis J. Frailey Reducing SW Cycle Time 11

11 Cycle Time Improvement Is Improving the Process 12 Copyright , Dennis J. Frailey Reducing SW Cycle Time 12

12 Cycle Time Improvement Is Improving the Process Reducing the Critical Path 13 Copyright , Dennis J. Frailey Reducing SW Cycle Time 13

13 Cycle Time Improvement Is Improving the Process Reducing the Critical Path Eliminating Waits, Queues, Bottlenecks 14 Copyright , Dennis J. Frailey Reducing SW Cycle Time 14

14 Cycle Time Improvement Is Improving the Process Reducing the Critical Path Eliminating Waits, Queues, Bottlenecks Helping People work Smarter 15 Copyright , Dennis J. Frailey Reducing SW Cycle Time 15

15 Cycle Time Improvement Is Improving the Process Reducing the Critical Path Eliminating Waits, Queues, Bottlenecks Helping People work Smarter Increased Cycles of Learning 16 Copyright , Dennis J. Frailey Reducing SW Cycle Time 16

16 Cycle Time Improvement Is Improving the Process Reducing the Critical Path Eliminating Waits, Queues, Bottlenecks Helping People work Smarter Increased Cycles of Learning Reengineering the Process 17 Copyright , Dennis J. Frailey Reducing SW Cycle Time 17

17 Three Fundamental Problems Variability Some parts of the process are starved while other parts are producing excessive output Performance becomes inconsistent and unreliable This is what causes traffic jams! Complex Processes More work to do than is necessary More opportunities to make mistakes Bottlenecks and Constraints Things that slow everything down 18 Copyright , Dennis J. Frailey Reducing SW Cycle Time 18

18 Typical Causes of Cycle Time Problems Misplaced Priorities Incompatible Tools Inefficient Procedures Poor Planning Variability Complexity Bottlenecks etc. 19 Copyright , Dennis J. Frailey Reducing SW Cycle Time 19

19 Spotting the Symptoms and the Opportunities Symptom: excess WIP or work in process work waiting to be done that is not being done -- waiting in queues instead something is holding up the process Causes: limited capacity, bottlenecks, poor processes, poor execution, various barriers imposed by the organization 20 Cycle Time = WIP (products being developed) THROUGHPUT (products produced/unit time) Copyright , Dennis J. Frailey Reducing SW Cycle Time 20

20 Examples of Excessive WIP for Software Code waiting to be tested Not enough test equipment? Poor test planning? Designs waiting to be coded Specifications waiting to be inspected Change requests waiting for approval People waiting for the network to come up Hundreds more Copyright , Dennis J. Frailey Reducing SW Cycle Time 21

21 Other Symptoms of Cycle Time Problems Long waits and queues High inventory levels Excessive overtime High levels of rework / scrap Tickets --> How long is this line? 22 Copyright , Dennis J. Frailey Reducing SW Cycle Time 22

22 Reducing Rework - The Impact of Defects on Cycle Time Defect Detected Process Step Undetected Defect Process Step Several Steps 23 Copyright , Dennis J. Frailey Reducing SW Cycle Time 23

23 Doing it Over Again Defect Detected Process Step Undetected Defect Process Step Several Steps Rework costs money and time 24 Copyright , Dennis J. Frailey Reducing SW Cycle Time 24

24 Look for Rework REWORK is anything you do because you didn t do it right the first time debugging correcting documentation correcting designs correcting requirements retesting responding to customer complaints 25 Copyright , Dennis J. Frailey Reducing SW Cycle Time 25

25 Isn t Rework Inevitable? SOME rework is necessary, but much of it is not Total rework is a measure of process efficiency You probably have a lot more rework than you think 26 Copyright , Dennis J. Frailey Reducing SW Cycle Time 26

26 Fixing the Problems -- Five Principles of Cycle Time Improvement Warning some of these are counter-intuitive Copyright , Dennis J. Frailey Reducing SW Cycle Time 27

27 Where are the Opportunities? ~30% of the improvement comes from technical changes Process changes Tool changes Changing rules and operations 28 Copyright , Dennis J. Frailey Reducing SW Cycle Time 28

28 Where are the Opportunities? ~70% of the improvement comes from organizational, cultural and environmental changes, such as Education Communication Management Teamwork 29 Copyright , Dennis J. Frailey Reducing SW Cycle Time 29

29 Principle #1 Look at the Entire Process Don t optimize only your local part of the process Speeding up every step of the process will cost a lot and will not help as much as speeding up the bottlenecks Beware of inappropriate reward systems! 30 Copyright , Dennis J. Frailey Reducing SW Cycle Time 30

30 Example Process Pizza Shop Take Order Toppings Where could the bottlenecks be? Deliver Box Crust Pizza Oven Slicer 31 Copyright , Dennis J. Frailey Reducing SW Cycle Time 31

31 Principle #2 Gain from Cycles of Learning Sometimes it is better to do the job many times, in small chunks, than to do it all at once Changes are received and processed here ( ) 32 Copyright , Dennis J. Frailey Reducing SW Cycle Time 32

32 Ways to Implement the Cycles of Learning Principle Try a new compiler or debugging tool on one module first to see how well it works Then decide whether to use it on more modules Write one module using the new language Then decide whether to use the new language on a larger scale Take one subset of the features through the whole process flow first to work out the quirks Test server performance using dummy data 33 Copyright , Dennis J. Frailey Reducing SW Cycle Time 33

33 Principle #3 Use Small Batches Important when requirements change a lot or the process is new The work to be done Batch 1 Rework 34 Batch 2 Rework Batch 3 Batch 4 Batch 5 Small batch principle - allows for finding errors and requirements changes without large amounts of rework Copyright , Dennis J. Frailey Reducing SW Cycle Time 34

34 Principle #4 Aim for Smooth Flow The typical process runs unevenly, like vehicles on a city street Lots of entrances and exits Vehicles of different sizes and speeds Some drivers uncertain of what they want to do Lots of stoplights to control the flow (mainly to prevent collisions) Note: streets are usually crowded 35 Copyright , Dennis J. Frailey Reducing SW Cycle Time 35

35 The Ideal is Smooth Flow The ideal process flows smoothly, like a train running on tracks Note: tracks are empty most of the time 36 Copyright , Dennis J. Frailey Reducing SW Cycle Time 36

36 What Prevents Smooth Flow? Bottlenecks and constraints that lead to: Queues and waits Work in process For example: Work piling up Machines or software not being available Excessive approval requirements People pulled off projects Excessive rework Product stuck in test Incoming work 37 Copyright , Dennis J. Frailey Reducing SW Cycle Time 37

37 Principle #5 Avoid the Naïve, Obvious and Wrong Solutions to Cycle Time Problems Such as Shortening the longest step of the process Shortening every step of the process Cutting the overhead without assessing the impact of the cut 38 Copyright , Dennis J. Frailey Reducing SW Cycle Time 38

38 Productivity is... The quality or state of being productive Webster s 9th New Collegiate Dictionary Productive: Having the power of producing; Yielding or furnishing results, benefits, or profits Webster s 9th New Collegiate Dictionary 39 Copyright , Dennis J. Frailey Reducing SW Cycle Time 39

39 Productivity is NOT being... Busy Industrious Virtuous Wealthy Hardworking etc. Productivity has to do with results (what and how much you produce), not with the means or methods of production or the characteristics of the producer 40 Copyright , Dennis J. Frailey Reducing SW Cycle Time 40

40 Measuring Productivity Productivity is usually measured in terms of how much you produce in relation to how much you invest Productivity = Output Input or Investment 41 Copyright , Dennis J. Frailey Reducing SW Cycle Time 41

41 Productivity Measures Products produced per labor hour Return on investment Bushels of grain per acre of land Modules tested per week Requirements validated per day A farmer who invents a new method of growing that doubles the output per acre would be more productive than a farmer who works longer hours and doubles output per acre. 42 Copyright , Dennis J. Frailey Reducing SW Cycle Time 42

42 A Few Lessons Learned Copyright , Dennis J. Frailey Reducing SW Cycle Time 43

43 Lesson Learned Be Careful Whom you Reward Know the difference between busy and productive Examine the value produced, not the effort spent 44 Employee A Works 8am 9pm Produces 10 code units per month Produces 3 bugs per unit Employee B Works 8am 5pm Produces 12 code units per month Produces 1.5 bugs per unit Copyright , Dennis J. Frailey Reducing SW Cycle Time 44

44 Lesson Learned Independent Observers May See Problems and Opportunities the Best Practitioners generally focus on their work and on what they THINK is happening rather than on what IS happening They tend not to see all of the waits, queues, etc. that they cause themselves Their perception of how they spend their time is generally incorrect They are too busy getting the job done to see how they might improve it 45 Copyright , Dennis J. Frailey Reducing SW Cycle Time 45

45 The Athletic Coach Analogy Just as athletes rely on coaches, software engineers need to learn to trust in others to observe and help them do better 46 Copyright , Dennis J. Frailey Reducing SW Cycle Time 46

46 Lesson Learned Software Developers Are Accustomed to Improving Cycle Time Think of your software development process as a large computer program that runs too slow. > How would you make it run faster? Imagine how you would speed up a computer program. Then draw analogies to the software development process And improve the process the way you would improve a program 47 Copyright , Dennis J. Frailey Reducing SW Cycle Time 47

47 Summary Background - Why Cycle Time is Important Cycle Time Reduction Issues and Examples Defining Cycle Time Three Fundamental Problems Typical Causes Spotting the Symptoms and Opportunities Fixing the Problems - Five Principles A Few Lessons Learned 48 Copyright , Dennis J. Frailey Reducing SW Cycle Time 48

48 References Deming, W. Edwards, Out of the Crisis, MIT Press, Goldratt, Eliyahu M. & Jeff Cox, The Goal, (North River Press, 1984.) Also, Theory of Constraints, It s Not Luck, and Critical Chain Management. Gross and Harris, Fundamentals of Queueing Theory (Wiley). Swartz, James B., The Hunters and the Hunted, (Portland, Oregon, Productivity Press, 1994) ISBN Copyright , Dennis J. Frailey Reducing SW Cycle Time 49

49 END Questions? Comments? Copyright , Dennis J. Frailey Reducing SW Cycle Time 50