Thursday 20 October 2016

Confusion Over Waste

When looking at the performance of our software we often have to consider both first-order and second-order effects. For example when profiling a native application where memory management is handled explicitly we can directly see the cost of allocations and deallocations because this all happens at the moment we make them. In contrast the world of garbage collected languages like C# exhibit different behaviour. The cost of memory allocations here are minimal because the algorithm is simple. However the deallocation story is far more complex, and it happens at a non-deterministic time later.

A consequence of this different behaviour is that it is much harder to see the effects that localised memory churn is having on your application. For example I once worked on a C# data transformation tool where the performance was appalling. Profiling didn’t immediately reveal the problem but closer inspection showed that the garbage collector was running full tilt. Looking much closer at the hottest part of the code I realised it was spending all it’s time splitting strings and throwing them away. The memory allocations were cheap so there were no first-order effects, but the clean-up was really expensive and happened later and therefore appeared as a second-order effect which was harder to trace back.

Short Term Gains

We see the same kind of effects occurring during the development process too. They are often masked though by the mistaken belief that time is being saved, it is, but only in the short term. The problem is the second-order effects of such time saving is actually lost later, and when it’s more precious.

This occurs because the near term activity is being seen as wasteful of a certain person’s time, on the premise that the activity is of low value (to them). But what is being missed is the second-order effects of doing that, such as the learning about the context, people and product involved. When crunch time comes that missed learning suddenly has to happen at the later time when potentially under time pressure or after money has already been spent; then you’re heading into sunk costs territory.

In essence what is being perceived as waste is the time spent in the short term, when the real waste is time lost in the future due to rework caused by the missed opportunity to learn sooner.

All Hail “Agile”

Putting this into more concrete terms consider a software development team where the developer’s time is assumed to be best spent designing and writing code. The project manager assumes that having conversations, perhaps with ops or parts of the business is of low value, from the developer’s perspective, and therefore decides it’s better if someone “less expensive” has it instead.

Of course we’re all “agile” now and we don’t do that anymore. Or do we? I’ve worked in supposedly agile teams and this problem still manifests itself, maybe not quite to the same extent as before, but nonetheless it still happens and I believe it happens because we are confused about what the real waste is that we’re trying to avoid.

Even in teams I’ve been in where we’ve tried to ensure this kind of problem is addressed, it’s only addressed locally, it’s still happening further up the food chain. For example a separate architecture team might be given the role of doing a spike around a piece of technology that a development team will be using. This work needs to happen inside the team so that those who will be developing and, more importantly, supporting the product will get the most exposure to it. Yes, there needs to be some governance around it, but the best people to know if it even solves their problem in the first place is the development team.

Another manifestation of this is when two programme managers are fed highlights about potential changes on their side of the fence. If there is any conflict there could be a temptation to resolve it without going any lower. What this does is cut out the people that not only know most about the conflict, but are also the best placed to negotiate a way out. For example instead of trying to compensate for a potential breaking change with a temporary workaround, which pushes the product away from its eventual goal, see if the original change can be de-prioritised instead. If a system is built in very small increments it’s much easier to shuffle around the high priority items to accommodate what’s happening around the boundaries of the team.

Time for Reflection

How many times have you said, or heard someone else say, “if only you’d come to us earlier”. This happens because we try and cut people out of the loop in the hope that we’ll save time by resolving issues ourselves, but what we rarely do is reflect on whether we really did save time in the long run when the thread eventually started to unravel and the second-order effects kicked in.

Hence, don’t just assume you can cut people out of the loop because you think you’re helping them out, you might not be. They might want to be included because they have something to learn or contribute over-and-above the task at hand. Autonomy is about choice, they might not always want it, but if you don’t provide it in the first place it can never be leveraged.

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