This week, we had a few weird crashes with an HTTP server which we could not easily reproduce and we had a hard time pin-pointing the source of the issue. We knew the problems were triggered by bad input, but since the process was continuously receiving around 3000 requests per second at the time, it was pretty hard to isolate the exact request(s) that made it crash.

The idea we had was to capture HTTP requests data up to the point where the process crashed. Then, we would open the trace and look for the last successful requests, the faulty one would be in there somewhere.

At work, we have been doing quite a few tests lately to understand what is the maximum number of http queries per second (QPS) that a modern server running Ubuntu 12.04 with a recent Linux kernel could handle.

Magnifique bloc classique de Val-David, l'Égyptien.

Pas de musique dans le video pour cette fois, seulement Pascal Visegrip qui commente. Cherchez bien et vous trouverez le thème du jour: le side core banana

While doing some packet drop testing for a pcap script I'm writing with a collegue a work, I hit a strange situation on my Mac where ab would do ~16k HTTP connections really fast, then stop, then timeout.

Turns out this is caused by the lack of available ephemeral port …

an overview of python modules wrapping libpcap

Pulled pork (prononcer Poulède porc), joli V7 avec petits crimps.

Travaillé à la fin d'une session l'automne dernier avec Pascalski et Davidski, pendant que les locaux faisaient du ski... La fin était impraticable (eneigée!)

Beau problème de crimps avec un crux mental au dernier mouvement. Réussi au premier essai, mais la caméra a capté seulement la fin de la séquence.

One move wonder Brutus, finalement complété le 2014-05-11 après un peu moins de mille essais en 2013...

If you're doing ip routing on a VMware virtual machine, make sure to disable Large Receive Offload (LRO) at the vmware level or it will fail in interesting ways.