Yung-Luen Lan yllan

## libdispatch-efficiency-tips.md

      
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                tclementdev
                / libdispatch-efficiency-tips.md
            
            
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              April 16, 2024 01:02
            
              
                Making efficient use of the libdispatch (GCD)
              
          
    libdispatch efficiency tips

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:


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.


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


## TaskConcurrencyManifesto.md

      
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                lattner
                / TaskConcurrencyManifesto.md
            
            
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              April 21, 2024 09:43
            
              
                Swift Concurrency Manifesto
              
          
    Swift Concurrency Manifesto

Author: Chris Lattner
Chinese Translation by Jason Yu
Contents


Introduction
Overall Vision


## ssd.c
// Copyright (C) 2010 Apple Inc. All Rights Reserved.

#include <launch.h>
#include <libkern/OSAtomic.h>
#include <vproc.h>
#include "shared.h"

static bool g_is_managed = false;
static bool g_accepting_requests = true;
static dispatch_source_t g_timer_source = NULL;

## test.html
<html>
<head>
</head>
<body>
  <script>
    var test = function (str) {
      with(Math) { // whatever
        var scalar = parseFloat(str);
        var unit = str.replace(/-?\d+(\.\d*)?/g, "");

## xcode_ramdisk.sh
#!/bin/sh
# Create a RAM disk with same perms as mountpoint
# Script based on http://itux.idev.pro/2012/04/iservice-speed-up-your-xcode-%D0%BD%D0%B5%D0%BA%D0%BE%D1%82%D0%BE%D1%80%D1%8B%D0%B5-%D1%81%D0%BF%D0%BE%D1%81%D0%BE%D0%B1%D1%8B/ with some additions
# Usage: sudo ./xcode_ramdisk.sh start

USERNAME=$(logname)

TMP_DIR="/private/tmp"
RUN_DIR="/var/run"

## nshipster-new-years-2015.md

      
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                mattt
                / nshipster-new-years-2015.md
            
            
              Created
              November 25, 2014 19:38
            
              
                NSHipster New Year's 2015
              
          
    Season's Greetings, NSHipsters!
As the year winds down, and we take a moment to reflect on our experiences over the past months, one thing is clear: 2014 has been an incredible year professionally for Apple developers. So much has happened in such a short timespan, and yet it's hard to remember our relationship to Objective-C before Swift, or what APIs could have captivated our imagination as much as iOS 8 or WatchKit.
It's an NSHipster tradition to ask you, dear readers, to send in your favorite tips and tricks from the past year for publication over the New Year's holiday. This year, with the deluge of new developments—both from Cupertino and the community at large—there should be no shortage of interesting tidbits to share.
Submit your favorite piece of Swift or Objective-C trivia, framework arcana, hidden Xcode feature, or anything else you think is cool, and you could have it featured in the year-end blowout article. Just comment on this gist below!
If you're wondering about what to post, look to

  
## 網路詐騙.md

      
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                maylogger
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    ???

特質


強調經驗勝過於實作
強調品味
從不分享實際工作經驗（有機會下次再分享）
強調單一專業的重要而忽略人性
不會寫完整的文件與簡報
討論實作時，強調自己是領導人性格，擅長帶人


## gist:3870064
/**
 * this is an experiment to create unboxed union types with a phantom type and a context bound.
 * All the good ideas come from @milessabin post, comments and links: http://www.chuusai.com/2011/06/09/scala-union-types-curry-howard/#comment-22
 */

/** trait for anything that can be A or B */
trait Or[A, B] {
  // a phantom type, there will be no instance of this type that we'll use
  type l[T]
  // an alias for l[t]

## gist:3661188
- (UIViewController *)topViewController{
  return [self topViewController:[UIApplication sharedApplication].keyWindow.rootViewController];
}

- (UIViewController *)topViewController:(UIViewController *)rootViewController
{
  if (rootViewController.presentedViewController == nil) {
    return rootViewController;
  }


## Golem.sh
# Build Golem
sbt assembly

# Run golem as daemon
nohup java -jar target/Golem-assembly-1.0.jar </dev/null &
	// Copyright (C) 2010 Apple Inc. All Rights Reserved.

	#include <launch.h>
	#include <libkern/OSAtomic.h>
	#include <vproc.h>
	#include "shared.h"

	static bool g_is_managed = false;
	static bool g_accepting_requests = true;
	static dispatch_source_t g_timer_source = NULL;
	<html>
	<head>
	</head>
	<body>
	<script>
	var test = function (str) {
	with(Math) { // whatever
	var scalar = parseFloat(str);
	var unit = str.replace(/-?\d+(\.\d*)?/g, "");
	#!/bin/sh
	# Create a RAM disk with same perms as mountpoint
	# Script based on http://itux.idev.pro/2012/04/iservice-speed-up-your-xcode-%D0%BD%D0%B5%D0%BA%D0%BE%D1%82%D0%BE%D1%80%D1%8B%D0%B5-%D1%81%D0%BF%D0%BE%D1%81%D0%BE%D0%B1%D1%8B/ with some additions
	# Usage: sudo ./xcode_ramdisk.sh start

	USERNAME=$(logname)

	TMP_DIR="/private/tmp"
	RUN_DIR="/var/run"
	/**
	* this is an experiment to create unboxed union types with a phantom type and a context bound.
	* All the good ideas come from @milessabin post, comments and links: http://www.chuusai.com/2011/06/09/scala-union-types-curry-howard/#comment-22
	*/

	/** trait for anything that can be A or B */
	trait Or[A, B] {
	// a phantom type, there will be no instance of this type that we'll use
	type l[T]
	// an alias for l[t]
	- (UIViewController *)topViewController{
	return [self topViewController:[UIApplication sharedApplication].keyWindow.rootViewController];
	}

	- (UIViewController )topViewController:(UIViewController )rootViewController
	{
	if (rootViewController.presentedViewController == nil) {
	return rootViewController;
	}
	# Build Golem
	sbt assembly

	# Run golem as daemon
	nohup java -jar target/Golem-assembly-1.0.jar </dev/null &