hellerbarde

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
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

denji

Moved to git repository: https://github.com/denji/nginx-tuning

NGINX Tuning For Best Performance

For this configuration you can use web server you like, i decided, because i work mostly with it to use nginx.

Generally, properly configured nginx can handle up to 400K to 500K requests per second (clustered), most what i saw is 50K to 80K (non-clustered) requests per second and 30% CPU load, course, this was 2 x Intel Xeon with HyperThreading enabled, but it can work without problem on slower machines.

You must understand that this config is used in testing environment and not in production so you will need to find a way to implement most of those features best possible for your servers.

richadams

#!/bin/bash
# Requires: awscli (http://aws.amazon.com/cli/)
# Prints out a list of all security groups and their settings, just for quickly auditing it.

# Your AWS credentials
if [ -z ${AWS_ACCESS_KEY_ID} ]; then
    export AWS_ACCESS_KEY_ID='***'
    export AWS_SECRET_ACCESS_KEY='***'
fi

ocornut

Memory Optimization (Christer Ericson, GDC 2003)
http://realtimecollisiondetection.net/pubs/GDC03_Ericson_Memory_Optimization.ppt

Cache coherency primer (Fabian Giesen)
https://fgiesen.wordpress.com/2014/07/07/cache-coherency/

Code Clinic 2015: How to Write Code the Compiler Can Actually Optimize (Mike Acton)
http://gdcvault.com/play/1021866/Code-Clinic-2015-How-to

jacoelho

#!/bin/bash

export GOLANG_VERSION=1.10.3
export GOLANG_DOWNLOAD_URL=https://golang.org/dl/go$GOLANG_VERSION.linux-amd64.tar.gz
export GOLANG_DOWNLOAD_SHA256=fa1b0e45d3b647c252f51f5e1204aba049cde4af177ef9f2181f43004f901035

apt-get update -qq 

apt-get install -y --no-install-recommends \
    g++ \

haje01

텐서플로우 시작하기

글쓴이: 김정주(haje01@gmail.com)

이 문서는 텐서플로우 공식 페이지 내용을 바탕으로 만들어졌습니다.

---

소개

텐서플로우(TensorFlow)는 기계 학습과 딥러닝을 위해 구글에서 만든 오픈소스 라이브러리입니다. 데이터 플로우 그래프(Data Flow Graph) 방식을 사용하였습니다.

kaustavha

Kafka-node consumer benchmark

This code can be used to benchmark throughput for a kafka cluster. Args:

groupId -- (str) kafka consumer group id, default: bench
concurrency -- (int) Number of worker threads to spawn, defaults to number of cpus on current host
duration -- (int) How long to run the benchmark for, default: 20s
topic -- (str) the kafka topic to consume from, defaults to observations.json
zk -- (str) zookeeper url, defaults to localhost:2181

bastman

Docker - How to cleanup (unused) resources

Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...

delete volumes

// see: https://github.com/chadoe/docker-cleanup-volumes

$ docker volume rm $(docker volume ls -qf dangling=true)

$ docker volume ls -qf dangling=true | xargs -r docker volume rm

maxvt

Currently, there is an explosion of tools that aim to manage secrets for automated, cloud native infrastructure management. Daniel Somerfield did some work classifying the various approaches, but (as far as I know) no one has made a recent effort to summarize the various tools.

This is an attempt to give a quick overview of what can be found out there. The list is alphabetical. There will be tools that are missing, and some of the facts might be wrong--I welcome your corrections. For the purpose, I can be reached via @maxvt on Twitter, or just leave me a comment here.

There is a companion feature matrix of various tools. Comments are welcome in the same manner.

danieleggert

GPG and git on macOS

Setup

No need for homebrew or anything like that. Works with https://www.git-tower.com and the command line.

1. Install https://gpgtools.org -- I'd suggest to do a customized install and deselect GPGMail.
2. Create or import a key -- see below for https://keybase.io
3. Run gpg --list-secret-keys and look for sec, use the key ID for the next step
4. Configure git to use GPG -- replace the key with the one from gpg --list-secret-keys