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@jboner
jboner / latency.txt
Last active November 18, 2024 08:23
Latency Numbers Every Programmer Should Know
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
@tsileo
tsileo / duptools.sh
Created July 19, 2012 22:08
A bash script to simplify backup management with duplicity (encrypted incremental backups on amazon S3)
#!/bin/bash
export AWS_ACCESS_KEY_ID=YOUR_ACCESS_KEY
export AWS_SECRET_ACCESS_KEY=YOUR_SECRET_ACCESS_KEY
export PASSPHRASE=YOU_PASSHRASE
# directories, space separated
SOURCE="/home/thomas/backup /home/thomas/bin /home/thomas/documents"
BUCKET=s3+http://mybucket
LOGFILE=/home/thomas/tmp/duplicity.log
# set email to receive a backup report
@rgreenjr
rgreenjr / postgres_queries_and_commands.sql
Last active November 17, 2024 13:10
Useful PostgreSQL Queries and Commands
-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query
FROM pg_stat_activity
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%'
ORDER BY query_start desc;
-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query
FROM pg_stat_activity
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%'
@xenomuta
xenomuta / httpd.asm
Last active January 4, 2024 13:53
httpd.asm: Arguably the world smallest web server. ( for GNU/Linux i386. Compile with nasm )
section .text
global _start
_start:
xor eax, eax
xor ebx, ebx
xor esi, esi
jmp _socket
_socket_call:
@aras-p
aras-p / preprocessor_fun.h
Last active November 15, 2024 09:22
Things to commit just before leaving your job
// Just before switching jobs:
// Add one of these.
// Preferably into the same commit where you do a large merge.
//
// This started as a tweet with a joke of "C++ pro-tip: #define private public",
// and then it quickly escalated into more and more evil suggestions.
// I've tried to capture interesting suggestions here.
//
// Contributors: @r2d2rigo, @joeldevahl, @msinilo, @_Humus_,
// @YuriyODonnell, @rygorous, @cmuratori, @mike_acton, @grumpygiant,
@Neal
Neal / savethemblobs.py
Last active November 29, 2016 19:48
A simple script to grab all SHSH blobs from Apple that it's currently signing to save them locally and on Cydia server. And now also grabs blobs already cached on Cydia and iFaith servers to save them locally. Updated version on GitHub: https://github.com/Neal/savethemblobs
#!/usr/bin/env python
#
# savethemblobs.py
# A simple script to grab all SHSH blobs from Apple that it's currently signing to save them locally and on Cydia server.
# And now also grabs blobs already cached on Cydia and iFaith servers to save them locally.
#
# Copyright (c) 2013 Neal <[email protected]>
#
# examples:
# savethemblobs.py 1050808663311 iPhone3,1
# GIT heart FZF
# -------------
is_in_git_repo() {
git rev-parse HEAD > /dev/null 2>&1
}
fzf-down() {
fzf --height 50% --min-height 20 --border --bind ctrl-/:toggle-preview "$@"
}
@anvk
anvk / psql_useful_stat_queries.sql
Last active October 18, 2024 23:47
List of some useful Stat Queries for PSQL
--- PSQL queries which also duplicated from https://github.com/anvk/AwesomePSQLList/blob/master/README.md
--- some of them taken from https://www.slideshare.net/alexeylesovsky/deep-dive-into-postgresql-statistics-54594192
-- I'm not an expert in PSQL. Just a developer who is trying to accumulate useful stat queries which could potentially explain problems in your Postgres DB.
------------
-- Basics --
------------
-- Get indexes of tables