Jean-Michaël Celerier jcelerier

## latency.markdown

      
              2 files
            
          
              742 forks
            
          
              50 comments
            
          
              4390 stars
            
          
                hellerbarde
                / latency.markdown
            
            
              Created
              May 31, 2012 13:16
                — forked from jboner/latency.txt
            
              
                Latency numbers every programmer should know
              
          
    Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

  
## fix-infinality.md

      
              1 file
            
          
              50 forks
            
          
              157 comments
            
          
              723 stars
            
          
                cryzed
                / fix-infinality.md
            
            
              Last active
              May 8, 2024 17:00
            
              
                A set of instructions on how to fix the harfbuzz + Infinality issue and restoring good-looking, Infinality-like font rendering.
              
          
    Disclaimer: Please follow this guide being aware of the fact that I'm not an expert regarding the things outlined below, however I made my best attempt. A few people in IRC confirmed it worked for them and the results looked acceptable.
Attention: After following all the steps run gdk-pixbuf-query-loaders --update-cache as root, this prevents various gdk-related bugs that have been reported in the last few hours. Symptoms are varied, and for Cinnamon the DE fails to start entirely while for XFCE the icon theme seemingly can't be changed anymore etc.
Check the gist's comments for any further tips and instructions, especially if you are running into problems!
Screenshots

Results after following the guide as of 11.01.2017 13:08:

  
## howtogif
How to convert a video file to an animated GIF on Linux:

Install required software:
apt-get install ffmpeg gifsicle imagemagick:
Convert the video file to a series of small images:
mkdir /tmp/gif/
ffmpeg -i YOURVIDEOFILE.mp4 -r 10 /tmp/gif/out%04d.gif
Combine these images together into a GIF animation:
gifsicle –delay=10 –loop /tmp/gif/*.gif > animation.gif
Optimise the GIF animation so the file size is smaller:

## encode.sh
ffmpeg -i input.mp4 -vcodec libx264 -pix_fmt yuv420p -profile:v baseline -level 3 -an -vf "scale=-1:1440, reverse" -preset veryslow -g 2 output.mp4

// -vcodec libx264 -pix_fmt yuv420p -profile:v baseline -level 3
// Encode for web with a good balance of browser compatibility and compression ratio

// -an
// Strip audio tracks

// -vf "scale=-1:1440, reverse"
// Scale video to 1440px wide, maintaining aspect ratio

## LICENSE
This work, excluding the Arch Linux logo, is made available under CC0: https://creativecommons.org/publicdomain/zero/1.0/

## vaapi_egl_interop_example.c
#if 0  // self-compiling code: chmod +x this file and run it like a script
BINARY=vaapi_egl_interop_example
gcc -std=c99 -Wall -Wextra -pedantic -Werror -g -fsanitize=address -o $BINARY $0 \
    `pkg-config libavcodec libavformat libavutil libva gl egl libdrm --cflags --libs` \
    -lX11 -lva-x11 -lva-drm || exit 1
test "$1" = "--compile-only" && exit 0
exec env ASAN_OPTIONS=fast_unwind_on_malloc=0 ./$BINARY $*
#endif  /*

Minimal example application for hardware video decoding on Linux and display

## magic_ring.cpp
#define _CRT_SECURE_NO_DEPRECATE

#include <stdio.h>
#include <string.h>
#include <Windows.h>

// This allocates a "magic ring buffer" that is mapped twice, with the two
// copies being contiguous in (virtual) memory. The advantage of this is
// that this allows any function that expects data to be contiguous in
// memory to read from (or write to) such a buffer. It also means that

## CMakeLists.txt
cmake_minimum_required(VERSION 2.8.11)

project(VtkFboInQtQuick)

set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_AUTOMOC ON)

find_package(VTK REQUIRED)
include(${VTK_USE_FILE})

## LICENSE
The MIT License (MIT)
Copyright (c) 2016 Luca Corbatto

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE

## send_fd.cpp
#include <boost/asio/coroutine.hpp>
#include <boost/asio/local/connect_pair.hpp>
#include <boost/asio/local/stream_protocol.hpp>
#include <iostream>
#include <sys/wait.h>

std::size_t
send_fd(boost::asio::local::stream_protocol::socket& socket,
        int fd,
        boost::system::error_code& ec)
	How to convert a video file to an animated GIF on Linux:

	Install required software:
	apt-get install ffmpeg gifsicle imagemagick:
	Convert the video file to a series of small images:
	mkdir /tmp/gif/
	ffmpeg -i YOURVIDEOFILE.mp4 -r 10 /tmp/gif/out%04d.gif
	Combine these images together into a GIF animation:
	gifsicle –delay=10 –loop /tmp/gif/*.gif > animation.gif
	Optimise the GIF animation so the file size is smaller:
	ffmpeg -i input.mp4 -vcodec libx264 -pix_fmt yuv420p -profile:v baseline -level 3 -an -vf "scale=-1:1440, reverse" -preset veryslow -g 2 output.mp4

	// -vcodec libx264 -pix_fmt yuv420p -profile:v baseline -level 3
	// Encode for web with a good balance of browser compatibility and compression ratio

	// -an
	// Strip audio tracks

	// -vf "scale=-1:1440, reverse"
	// Scale video to 1440px wide, maintaining aspect ratio
	#if 0 // self-compiling code: chmod +x this file and run it like a script
	BINARY=vaapi_egl_interop_example
	gcc -std=c99 -Wall -Wextra -pedantic -Werror -g -fsanitize=address -o $BINARY $0 \
	`pkg-config libavcodec libavformat libavutil libva gl egl libdrm --cflags --libs` \
	-lX11 -lva-x11 -lva-drm \|\| exit 1
	test "$1" = "--compile-only" && exit 0
	exec env ASAN_OPTIONS=fast_unwind_on_malloc=0 ./$BINARY $*
	#endif /*

	Minimal example application for hardware video decoding on Linux and display
	#define _CRT_SECURE_NO_DEPRECATE

	#include <stdio.h>
	#include <string.h>
	#include <Windows.h>

	// This allocates a "magic ring buffer" that is mapped twice, with the two
	// copies being contiguous in (virtual) memory. The advantage of this is
	// that this allows any function that expects data to be contiguous in
	// memory to read from (or write to) such a buffer. It also means that
	cmake_minimum_required(VERSION 2.8.11)

	project(VtkFboInQtQuick)

	set(CMAKE_INCLUDE_CURRENT_DIR ON)
	set(CMAKE_AUTOMOC ON)

	find_package(VTK REQUIRED)
	include(${VTK_USE_FILE})
	The MIT License (MIT)
	Copyright (c) 2016 Luca Corbatto

	Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

	The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
	#include <boost/asio/coroutine.hpp>
	#include <boost/asio/local/connect_pair.hpp>
	#include <boost/asio/local/stream_protocol.hpp>
	#include <iostream>
	#include <sys/wait.h>

	std::size_t
	send_fd(boost::asio::local::stream_protocol::socket& socket,
	int fd,
	boost::system::error_code& ec)