Tim Carlson timgcarlson

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

#!/usr/bin/env bash

# Assuming OS X Yosemite 10.10.4

# Install XCode and command line tools
# See https://itunes.apple.com/us/app/xcode/id497799835?mt=12#
# See https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/xcode-select.1.html
xcode-select --install

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	## Unity ##

	*.cs diff=csharp text
	*.cginc text
	*.shader text

	*.mat merge=unityyamlmerge eol=lf
	*.anim merge=unityyamlmerge eol=lf
	*.unity merge=unityyamlmerge eol=lf
	*.prefab merge=unityyamlmerge eol=lf

	/* DeviceUID.h
	#import <Foundation/Foundation.h>

	@interface DeviceUID : NSObject
	+ (NSString *)uid;
	@end
	*/


	// Device.m

	#!/usr/bin/env python
	# -- coding: utf-8 --

	# Localize.py - Incremental localization on XCode projects
	# João Moreno 2009
	# http://joaomoreno.com/

	# Modified by Steve Streeting 2010 http://www.stevestreeting.com
	# Changes
	# - Use .strings files encoded as UTF-8