Author: Chris Lattner
THIS GIST WAS MOVED TO TERMSTANDARD/COLORS
REPOSITORY.
PLEASE ASK YOUR QUESTIONS OR ADD ANY SUGGESTIONS AS A REPOSITORY ISSUES OR PULL REQUESTS INSTEAD!
State machines are everywhere in interactive systems, but they're rarely defined clearly and explicitly. Given some big blob of code including implicit state machines, which transitions are possible and under what conditions? What effects take place on what transitions?
There are existing design patterns for state machines, but all the patterns I've seen complect side effects with the structure of the state machine itself. Instances of these patterns are difficult to test without mocking, and they end up with more dependencies. Worse, the classic patterns compose poorly: hierarchical state machines are typically not straightforward extensions. The functional programming world has solutions, but they don't transpose neatly enough to be broadly usable in mainstream languages.
Here I present a composable pattern for pure state machiness with effects,
If your system is running slowly, perhaps a process is using too much CPU time and won't let other processes run smoothly. To find out which processes are taking up a lot of CPU time, you can use Apple's Activity Monitor.
The CPU pane shows how processes are affecting CPU (processor) activity:
#!/usr/bin/env bash | |
function p() { | |
jq -n \ | |
--arg content "$*" \ | |
'{ | |
"model": "pplx-7b-online", | |
"messages": [ | |
{ | |
"role": "system", | |
"content": "Be precise and concise." |
The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).
My take-aways are:
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You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.
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Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse
When VPNs Just Work™, they're a fantastic way of allowing access to a private network from remote locations. When they don't work it can be an experience in frustration. I've had situations where I can connect to a VPN from my Mac, but various networking situations cause routing conflicts. Here are a couple of cases and how I've been able to get around them.
In this example the VPN we are connecting to has a subnet that does not conflict with our local IP, but has additional routes that conflict in some way with our local network's routing. In my example the remote subnet is 10.0.x.0/24, my local subnet is 10.0.y.0/24, and the conflicting route is 10.0.0.0/8. Without the later route, I can't access all hosts on the VPN without manually adding the route after connecting to the VPN:
This document is research for the selection of a communication platform for robot-net.
The purpose of this component is to enable rapid, reliable, and elegant communication between the various nodes of the network, including controllers, sensors, and actuators (robot drivers). It will act as the core of robot-net to create a standardized infrastructure for robot control.
Requirements:
This gist assumes:
- you have a local git repo
- with an online remote repository (github / bitbucket etc)
- and a cloud server (Rackspace cloud / Amazon EC2 etc)
- your (PHP) scripts are served from /var/www/html/
- your webpages are executed by apache
- apache's home directory is /var/www/