| Latency Comparison Numbers (~2012) | |
| ---------------------------------- | |
| L1 cache reference 0.5 ns | |
| Branch mispredict 5 ns | |
| 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 us | |
| Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
| Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |
| # version 2.5.0 | |
| $wget https://github.com/google/protobuf/releases/download/v2.5.0/protobuf-2.5.0.tar.bz2 | |
| $tar xvf protobuf-2.5.0.tar.bz2 | |
| $cd protobuf-2.5.0 | |
| $./configure CC=clang CXX=clang++ CXXFLAGS='-std=c++11 -stdlib=libc++ -O3 -g' LDFLAGS='-stdlib=libc++' LIBS="-lc++ -lc++abi" | |
| $make -j 4 | |
| $sudo make install | |
| $protoc --version | |
| # version 2.4.1 |
"For comprehension" is a another syntaxe to use map, flatMap and withFilter (or filter) methods.
yield keyword is used to aggregate values in the resulting structure.
This composition can be used on any type implementing this methods, like List, Option, Future...
| trait Expr { | |
| def eval: Int = this match { | |
| case Number(n) => n | |
| case Sum(e1, e2) => e1.eval + e2.eval | |
| } | |
| } | |
| case class Number(n: Int) extends Expr | |
| case class Sum(e1: Expr, e2: Expr) extends Expr | |
| case class Prod(e1: Expr, e2: Expr) extends Expr | |
| case class Var(x: String) extends Expr |
| """ | |
| This module adds Redis Sentinel transport support to Celery. | |
| Current version of celery doesn't support Redis sentinel client, which is must have for automatic failover. | |
| To use it:: | |
| import register_celery_alias | |
| register_celery_alias("redis-sentinel") | |
| celery = Celery(..., broker="redis-sentinel://...", backend="redis-sentinel://...") |
| * Generate classes like WhereNot automatically with class decorator? | |
| * Haskell style deconstruction, perhaps like: | |
| @pmatch | |
| def count(first_arg=Match(x=Head, *xs=Rest)): | |
| print x, xs | |
| Will require some nasty hacks like https://github.com/smcq/python-inject | |
| * Implement boolean operators for stuff like: | |
| @pmatch |