rr is a lightweight tool for recording and replaying execution of applications (trees of processes and threads). More information about the project, including instructions on how to install, run, and build rr, is at http://rr-project.org.

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns on recent CPU
L2 cache reference ........................... 7 ns 14x L1 cache
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns 20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy ............. 3,000 ns = 3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns = 20 µs
SSD random read ........................ 150,000 ns = 150 µs
Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs 4X memory
Round trip within same datacenter ...... 500,000 ns = 0.5 ms 20x datacenter roundtrip
Read 1 MB sequentially from SSD* ..... 1,000,000 ns = 1 ms 80x memory, 20X SSD
Disk seek ........................... 10,000,000 ns = 10 ms
Read 1 MB sequentially from disk .... 20,000,000 ns = 20 ms
Send packet CA->Netherlands->CA .... 150,000,000 ns = 150 ms
LTO4 tape seek/access time ...... 55.000.000.000 ns = 55 s

The development of caches and caching is one of the most significant events in the history of computing. Virtually every modern CPU core from ultra-low power chips like the ARM Cortex-A5 to the highest-end Intel Core i7 use caches. Even higher-end microcontrollers often have small caches or offer them as options — the performance benefits are too significant to ignore, even in ultra low-power designs.

How does unicode works, pitfall etc

Namely, how can we merge multiple type-erased interfaces into one single interface. A similar question is also asked in the end of the first talk: How to apply type erasure to types with overlapping interfaces?

GCC recently (version 4.9) gained Undefined Behavior Sanitizer (ubsan), a run-time checker for the C and C++ languages. In order to check your program with ubsan, compile and link the program with -fsanitize=undefined option. Such instrumented binaries have to be executed; if ubsan detects any problem, it outputs a “runtime error:” message, and in most cases continues executing the program.

Clôner une VM Virtualbox entraîne la création d'un nouveau "Hardware UUID" qui cause la perte de l'activation de Windows sur la copie.

Pour résoudre le problème, il faut appliquer le même "Hardware UUID" au clône.

Clôner la machine virtuelle depuis l'interface VirtualBox (clic droit / clôner)
Ouvrir une ligne de commande et saisir :

C:\Program Files\Oracle\VirtualBox\vboxmanage showvminfo NomDeLaMachineSource

(il faut respecter la casse dans le nom de la machine source)

Chercher dans le résultat de la commande "Hardware UUID:" et copier l'UUID correspondant.

On va maintenant appliquer cet UUID à la nouvelle machine :

C:\Program Files\Oracle\VirtualBox\vboxmanage modifyvm NomMachineCible --hardwareuuid f9c76ae5-044f-49a3-b493-82d859cfbc64

Windows devrait maintenant considérer la clef de licence comme valide et enregistrée.

Create a backend module for llvm

git-remote-hg
git-remote-bzr

A list of c++'s containers and how to choose a container in c++.