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

gtallen1187

"A little bit of slope makes up for a lot of y-intercept"

01/13/2012. From a lecture by Professor John Ousterhout at Stanford, class CS140

Here's today's thought for the weekend. A little bit of slope makes up for a lot of Y-intercept.

[Laughter]

chranderson

// check version
node -v || node --version

// list locally installed versions of node
nvm ls

// list remove available versions of node
nvm ls-remote

// install specific version of node

miguelgrinberg

import asyncio
loop = asyncio.get_event_loop()

async def hello():
    await asyncio.sleep(3)
    print('Hello!')
    
if __name__ == '__main__':
    loop.run_until_complete(hello())
    

ptarjan

Scaling your API with rate limiters

The following are examples of the four types rate limiters discussed in the accompanying blog post. In the examples below I've used pseudocode-like Ruby, so if you're unfamiliar with Ruby you should be able to easily translate this approach to other languages. Complete examples in Ruby are also provided later in this gist.

In most cases you'll want all these examples to be classes, but I've used simple functions here to keep the code samples brief.

Request rate limiter

This uses a basic token bucket algorithm and relies on the fact that Redis scripts execute atomically. No other operations can run between fetching the count and writing the new count.

antirez

# LVDB - LLOOGG Memory DB
# Copyriht (C) 2009 Salvatore Sanfilippo <[email protected]>
# All Rights Reserved

# TODO
# - cron with cleanup of timedout clients, automatic dump
# - the dump should use array startsearch to write it line by line
#   and may just use gets to read element by element and load the whole state.
# - 'help','stopserver','saveandstopserver','save','load','reset','keys' commands.
# - ttl with milliseconds resolution 'ttl a 1000'. Check ttl in dump!

timvisee

Falsehoods programmers believe about time

This is a compiled list of falsehoods programmers tend to believe about working with time.

Don't re-invent a date time library yourself. If you think you understand everything about time, you're probably doing it wrong.

Falsehoods

• There are always 24 hours in a day.
• February is always 28 days long.
• Any 24-hour period will always begin and end in the same day (or week, or month).

francbartoli

# From https://github.com/tiangolo/fastapi/issues/258

from typing import List

from fastapi import FastAPI
from starlette.responses import HTMLResponse
from starlette.websockets import WebSocket, WebSocketDisconnect


app = FastAPI()

Jarmos-san

# Set the working directory globally
ARG SOURCEDIR="app"

# Pin the Python version to use
# See the following article to learn more about choosing the right base image
# https://pythonspeed.com/articles/base-image-python-docker-images
ARG PYTHONVERSION="3.11-slim-bookworm"

# Createh the base image for generating the requirements file
FROM python:${PYTHONVERSION} AS builder

IshaanAdarsh

Google Summer of Code 2023 Final Work Product

Introduction