Friday, 20 December 2013

Debunking the stupid myth that performance is a technical concern

I often hear people saying that latencies and response times are not business topics. I strongly disagree with that vision, and I like the punch-line used by Gojko here: “Debunking the stupid myth that performance is a technical concern”.

Indeed, It’s a fact that extra latencies or bad response times strongly impact the business. As a customer, I can’t stand to wait ages (even minutes;-) until someone (a salesman, a web site,…) is able to answer my questions, or to help me to quickly buy and checkout the product I already identified myself. It’s rather more true nowadays where our expectation level has been dramatically increased with our mobile phone usages.

Asking our business questions like : “what are your objective in term of performance?” is rarely productive. With such approach, we usually end up with average values for our implementation. Clearly the kind of setup fully loaded of implicit, leading to unclear situations,inappropriate architecture choices, and often crisis and strong tensions when we experience fires under production. Sad panda ;-(

On the other hand, by asking our business questions such as “ok, you want an average response time of 1 second, but is it ok for some things to take more than 10 minutes once a day?”, we can start to obtain reactions, deeper involvement, and answers that will  help us to build and validate the service level expectation we need to leverage on.

By leveraging on, I mean: to be verified via a continuous performance test harness, and carefully monitored under production (capacity management). A much more mature way of supporting the business of our clients.

I’d like to end this post with a reference to the excellent presentation of Gil TENE: “How NOT to measure latency”. In particular, Gil is sharing with us the typical kind of questions he asks to his clients in order to establish the performance requirements/service level expectations. 

The outcome of such exercise is something like:
  • 50% better than 20msec
  • 90% better than 50msec
  • 99.9% better than 500msec
  • 100% better than 2 seconds

The entire presentation worth the look, but the typical questions for the interview are showed from the slide #98.

Very useful…

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