start new:
tmux
start new with session name:
tmux new -s myname
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 |
#include <iostream> | |
#include <stdexcept> | |
#include <vector> | |
#include <string> | |
#include <cstring> | |
#include <locale> | |
#include <boost/property_tree/json_parser.hpp> | |
using namespace std; | |
class CodeCvt |
import shapeless._ | |
import scalaz._ | |
import Scalaz._ | |
object console extends App { | |
trait Foo[A] { | |
type B | |
def value: B |
Copyright © 2016-2018 Fantasyland Institute of Learning. All rights reserved.
A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.
val square : Int => Int = x => x * x
kubectl get pods | grep Evicted | awk '{print $1}' | xargs kubectl delete pod |
I was talking to a coworker recently about general techniques that almost always form the core of any effort to write very fast, down-to-the-metal hot path code on the JVM, and they pointed out that there really isn't a particularly good place to go for this information. It occurred to me that, really, I had more or less picked up all of it by word of mouth and experience, and there just aren't any good reference sources on the topic. So… here's my word of mouth.
This is by no means a comprehensive gist. It's also important to understand that the techniques that I outline in here are not 100% absolute either. Performance on the JVM is an incredibly complicated subject, and while there are rules that almost always hold true, the "almost" remains very salient. Also, for many or even most applications, there will be other techniques that I'm not mentioning which will have a greater impact. JMH, Java Flight Recorder, and a good profiler are your very best friend! Mea
/* | |
scalaVersion := "2.12.7" | |
resolvers += Resolver.sonatypeRepo("snapshots") | |
libraryDependencies += "co.fs2" %% "fs2-core" % "1.0.1-SNAPSHOT" | |
*/ | |
import cats._ | |
import cats.implicits._ | |
import cats.effect._ |