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Affichage des articles du 2018

How-to run QGIS 2 and QGIS 3 at the same time in Archlinux or Manjaro

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Since QGIS 3 was released, it's a nice and very pleasant upgrade. Unfortunately some plugins I use does still not work with Qgis 3 due to python upgrade from version 2 to 3.
It's possible to upgrade with tools like 2to3 (If interested, I suggest to watch Heikki Vesanto blog : https://gisforthought.com/updating-a-plugin-from-qgis-2-to-qgis-3/ ) but some plugins needs time to debug.

That's why, it's interesting during migration to have Qgis 2 and 3 at the same time in one computer. It's also possible to run Qgis 2 and 3 at the same time due to profile migration. They are not sharing same preferences folder so you are not breaking anything.
It's possible to have Qgis 2 and 3 running at the time with different way like Conda or Docker. But it's lightest to run it natively.

Archlinux/Manjaro is the Linux distribution I use. It have in my opinion a powerfull little thing called AUR (Arch User Repository) which automate installation of software. Furthermore, if y…

Resume script back from hibernation with systemd for wifi problem

I wrote a simple article which I found in my own opinion usefull ! I still need user manual when I use systemd and I still remember init.d command :-/

Since systemd, I am in an annoying situation when my desktop computer come back from hibernation :
- Network is unresponsive, Network Manager icon on mate desktop show a disable network,
- Command line on desktop and tty are working but you could send a command but never get this command sending to system. It's like freezing but system is still here !

The only workaround in a first time is to detach my TP-LINK TL-WN722N and to reconnect it. No error message in logs about chipset of this usb wifi device which is from Atheros and uses ath9k driver.

Next step to debug is to simulate behaviour but the only thing what I can do is disable ath9k driver before hibernation and renabling them after resume.
For those how wanted to know commands are like that :
Before hibernation disable modules :
rmmod ath9k_htc
rmmod ath9k_common
rmmod ath9k_hw
rm…

My GIS performance impact of Meltdown and Spectre patches

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When I saw performance regression few days ago of Meltdown and Spectre patch from cpu conception problem, I would like to perform some basic test to understand if it could slow down my process.

For those who don't know, here : a postgres article about performance regression : https://www.postgresql.org/message-id/20180102222354.qikjmf7dvnjgbkxe@alap3.anarazel.de 
Since some users finished to make benchmark with Meltdown and Spectre patch, I will not test it on my computer.

How to test  ?
First, I tested it on Archlinux based distribution named Manjaro Linux.


To know if patch is applied to my kernel, I just run this command :

$ cat /proc/cpuinfo | grep cpu_insecure Which reports this :

bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure
bugs        : cpu_insecure When showing cpu_insecure, you know that KPTI patch is enable.

Then there is a specific C code…