GCC Compiler Optimizations: Dissection of a Benchmark

Misja Alma

The idea of this post came from another blogpost which compared the performance of a little benchmark in C, Go and Python. The surprising result in that blog was, that the Go implementation performed much better than the C version.

The benchmark was a simple program took one command line argument and computed the sum of all integers up until the argument.
I wanted to see what was going on so I tried to run it locally and indeed, when invoked with a parameter 100,000,000 it took 0.259 seconds for the C implementation to finish and only 0.140 seconds for the Go version.

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The Union-Find Algorithm in Scala: a Purely Functional Implementation

Misja Alma

In this post I will implement the union-find algorithm in Scala, first in an impure way and then in a purely functional manner, so without any state or side effects. Then we can check both implementations and compare the code and also the performance.

The reason I chose union-find for this blog is that it is relatively simple. It is a classic algorithm that is used to solve the following problem: suppose we have a set of objects. Each of them can be connected to zero or more others. And connections are transitive: if A is connected to B and B is connected to C, then A is connected to C as well. Now we take two objects from the set, and we want to know: are they connected or not?
This problem comes up in a number of area's, such as in social networks (are two people connected via friends or not), or in image processing (are pixels connected or separated).
Because the total number of objects and connections in the set might be huge, the performance of the algorithm is important.

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HTTP/2 Server Push

Arnout Engelen

The HTTP/2 standard was finalized in May 2015. Most major browsers support it, and Google uses it heavily.

HTTP/2 leaves the basic concepts of Requests, Responses and Headers intact. Changes are mostly at the transport level, improving the performance of parallel requests - with few changes to your application. The go HTTP/2 'gophertiles' demo nicely demonstrates this effect.

A new concept in HTTP/2 is Server Push, which allows the server to speculatively start sending resources to the client. This can potentially speed up initial page load times: the browser doesn't have to parse the HTML page and find out which other resources to load, instead the server can start sending them immediately.

This article will demonstrate how Server Push affects the load time of the 'gophertiles'.
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Apache Spark

Jan Toebes

Spark is the new kid on the block when it comes to big data processing. Hadoop is also an open-source cluster computing framework, but when compared to the community contribution, Spark is much more popular. How come? What is so special and innovative about Spark? Is it that Spark makes big data processing easy and much more accessible to the developer? Or is it because the performance is outstanding, especially compared to Hadoop?

This article gives an introduction to the advantages of current systems and compares these two big data systems in depth in order to explain the power of Spark.

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Agile: how hard can it be?!

Chris Lukassen

Yesterday my colleagues and I ran an awesome workshop at the MIT conference in which we built a Rube Goldberg machine using Scrum and Extreme Engineering techniques. As agile coaches one would think that being an Agile team should come naturally to us, but I'd like to share our pitfalls and insights with you since "we learned a lot" about being an agile team and what an incredible powerful model a Rube Goldberg machine is for scaled agile product development.

If you're not the reading type, check out the video.

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About snowmen and mathematical proof why agile works

Chris Lukassen

Last week I had an interesting course by Roger Sessions on Snowman Architecture. The perishable nature of Snowmen under any serious form of pressure fortunately does not apply to his architecture principles, but being an agile fundamentalist I noticed some interesting patterns in the math underlying the Snowmen Architecture that are well rooted in agile practices. Understanding these principles may give facts to feed your gut feeling about these philosophies and give mathematical proof as to why Agile works.

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Why 'Why' Is Everything

Pieter Rijken

The 'Why' part is perhaps the most important aspect of a user story. This links to the sprint goal which links ultimately to the product vision and organisation's vision.

Lately, I got reminded of the very truth of this statement.  Read more

Become high performing. By being happy.  

Paul Takken

The summer holidays are over. Fall is coming. Like the start of every new year, a good moment for new inspiration.

Recently, I went twice to the Boston area for a client of Xebia. I met there (I dislike the word “assessments"..) a number of experienced Scrum teams. They had an excellent understanding of Scrum, but were not able to convert this to an excellent performance. Actually, there were somewhat frustrated and their performance was slightly going down.

So, they were great teams, great team members, their agile processes were running smoothly, but still not a single winning team. Which left in my opinion only one option: a lack of Spirit.   Spirit is the fertilizer of Scrum and actually every framework, methodology and innovation.  But how to boost the spirit?
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Help! Too Many Incidents! - Capacity Assignment Policy In Agile Teams

Pieter Rijken

As an Agile coach, scrum master, product owner, or team member you probably have been in the situation before in which more work is thrown at the team than the team has capacity to resolve.

In case of work that is already known this basically is a scheduling problem of determining the optimal order that the team will complete the work so as to maximise the business value and outcome. This typically applies to the case that a team is working to build or extend a new product.

The other interesting case is e.g. operational teams that work on items that arrive in an ad hoc way. Examples include production incidents. Work arrives ad hoc and the product owner needs to allocate a certain capacity of the team to certain types of incidents. E.g. should the team work on database related issues, or on front-end related issues?

If the team has more than enough capacity the answer is easy: solve them all! This blog will show how to determine what capacity of the team is best allocated to what type of incident.

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Why even Spray-can is Way Too Slow (for my purposes)

Wilco Koorn

In a previous blog I discussed the speed of the Spray-can web-server and mentioned some measurements I did. My co-worker Age Mooij, committer on the Spray project, pointed me at 'weighttp' (see weighttp at github) a tool for benchmarking web servers. Cool! Of course I now had to do more experiments and so I did. I found out Spray-can is way too slow for my purposes and here's why.
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