jboner

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

hrldcpr

One-line Tree in Python

Using Python's built-in defaultdict we can easily define a tree data structure:

def tree(): return defaultdict(tree)

That's it!

bjaglin

#!/bin/bash

set -eu
shopt -s nullglob

readonly base_dir=/var/lib/docker/registry
readonly output_dir=$(mktemp -d -t trace-images-XXXX)
readonly jq=/usr/bin/jq

readonly repository_dir=$base_dir/repositories

gsakkis

from binascii import hexlify, unhexlify
from hashlib import md5
from Crypto.Cipher import AES
try:
    from M2Crypto import EVP
except ImportError:
    EVP = None


def m2_encrypt(plaintext, key, iv, key_as_bytes=False, padding=True):

tonyc

Using strace and lsof to debug blocked processes

You can use strace on a specific pid to figure out what a specific process is doing, e.g.:

strace -fp <pid>

You might see something like:

select(9, [3 5 8], [], [], {0, 999999}) = 0 (Timeout)

pokstad

import redis
import web

SESSION = 'SESSION:'

class RedisStore(web.session.Store):

    """Store for saving a session in redis:
    import rediswebpy
    session = web.session.Session(app, rediswebpy.RedisStore(), initializer={'count': 0})

mmourafiq

# -*- coding: utf-8 -*-
'''
Created on Jan 11, 2013

@author: Mourad Mourafiq

About: This is an attempt to solve the Quora challenge Feed Optimizer.
'''
import itertools
import copy