One year at Intersec (actually two)

Jeez! It’s been a year already! A year working at Intersec… Time goes by so quickly! A year ago, I was thinking about giving up the idea of appending “PhD” to my name: I quit the graduate program I was in after only 10 months. Before that I had been working for a year at this other company called… wait! Was it Intersec already? Oh my God! It was! Intersec? Really?

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Blocks rewriting with clang

Introduction Back in 2009, Snow Leopard was quite an exciting OS X release. It didn’t focus on new user-visible features but instead introduced a handful of low level technologies. Two of those technologies Grand Central Dispatch (a.k.a. GCD) and OpenCL were designed to help developers benefit from the new computing power of modern computer architectures: multicore processors for the former and GPUs for the latter. Alongside the GCD engine came a C language extension called blocks.

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Hackathon 0x1 – Pimp my Review or the Epic Birth of a Gerrit Plugin

This series of articles describes some of the best realisations made by Intersec R&D team during the 2-day Hackathon that took place on the 3rd and 4th of July. The goal had been set a day or two prior to the beginning of the hackathon: we were hoping to make Gerrit better at recommending relevant reviewers for a given commit. To those who haven’t heard of it, Gerrit is a web-based code review system.

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Memory – Part 6: Optimizing the FIFO and Stack allocators

Introduction The most used custom allocators at Intersec are the FIFO and the Stack allocators, detailed in a previous article. The stack allocator is extremely convenient, thanks to the t_scope macro, and the FIFO is well fitted to some of our use cases, such as inter-process communication. It is thus important for these allocators to be optimized extensively. We are two interns at Intersec, and our objective for this 6 week internship was to optimize these allocators as far as possible.

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Hackathon 0x1 – Interactive mode in Behave

This series of articles describes some of the best realisations made by Intersec R&D team during the 2-day Hackathon that took place on the 3rd and 4th of July. Presentation of the Project As testers, we spend a lot of time working on behave, our test automation framework1. Our test framework is a great tool, but it takes a lot of time starting and initializing the product, running tests one by one.

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DAZIO: Detecting Activity Zones based on Input/Output sms and calls activity for geomarketing and trade area analysis

Introduction Telecom data is a rich source of information for many purposes, ranging from urban planning (Toole et al., 2012), human mobility patterns (Ficek and Kencl, 2012; Gambs et al., 2011), points of interest detection (Vieira et al., 2010), epidemic spread modeling (Lima et al., 2013), community detection (Morales et al., 2013) disaster planning (Pulse, 2013) and social interactions (Eagle et al., 2013). One common task for these applications is to identify dense areas where many users stay for a significant time (activity zones), the regions relaying theses activity zones (transit zones) as well as the interaction between identified activity zones.

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More about locality

In the third post of the memory series, we briefly explained locality and why it is an important principle to keep in mind while developing a memory-intensive program. This new post is going to be more concrete and explains what actually happens behind the scene in a very simple example. This post is a follow-up to a recent interview with a (brilliant) candidate1. As a subsidiary question, we resented him with the following two structure definitions:

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Memory – Part 5: Debugging Tools

Introduction Here we are! We spent 4 articles explaining what memory is, how to deal with it and what are the kind of problems you can expect from it. Even the best developers write bugs. A commonly accepted estimation seems to be around of few tens of bugs per thousand of lines of code, which is definitely quite huge. As a consequence, even if you proficiently mastered all the concepts covered by our articles, you’ll still probably have a few memory-related bugs.

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Memory - Part 4: Intersec’s custom allocators

malloc() not the one-size-fits-all allocator malloc() is extremely convenient because it is generic. It does not make any assumptions about the context of the allocation and the deallocation. Such allocators may just follow each other, or be separated by a whole job execution. They may take place in the same thread, or not… Since it is generic, each allocation is different from each other, meaning that long term allocations share the same pool as short term ones.

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Memory - Part 3: Managing memory

Developer point of view In the previous articles we dealt with memory classification and analysis from an outer point of view. We saw that memory can be allocated in different ways with various properties. In the remaining articles of the series we will take a developer point of view. At Intersec we write all of our software in C, which means that we are constantly dealing with memory management. We want our developers to have a solid knowledge of the various existing memory pools.

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