Ashfaqur Rahaman aagontuk

ELF Format Cheatsheet

Introduction

Executable and Linkable Format (ELF), is the default binary format on Linux-based systems.

Compilation

Program Analysis Resources

(draft; work in progress)

CPU Affinity

In a single core system, the OS allows multiple processes to run by sharing CPU time with the multiple processes. This is called concurrency, which gives the illusion of multiple processes executing at once, but is in fact just using a scheduler to give each process dedicated time on the CPU. The time associated with switching processes on a single core is overhead caused by context switching.

When a multi-core processor is available to an OS (e.g., Linux), the scheduler will do its best to allow processes to run simultaneously (by placing processes on different cores) in addition to running concurrently (different processes on the same core).

To control which core a process runs on, we can tell the scheduler to give a process a certain affinity towards a given set of CPUs.

Using taskset, we can get/set the CPU affinity of a particular process. Consider the following example.

GNU Make Cheatsheet

Based on https://www.gnu.org/software/make/manual/html_node/Quick-Reference.html

Directives

Directive	Description
`define variable` `define variable =` `define variable :=` `define variable ::=` `define variable +=` `define variable ?=` `endef`	Define multi-line variables.
`undefine variable`	Undefining variables.

Editing remote files in Vim with SSH

Configure SSH

In ~/.ssh/config, include the lines:
```
Host *
ControlPath ~/.ssh/sockets/%r@%h-%p
```

How to add a collapsible section in markdown

1. Example

Click me

Heading

Foo
Bar
- Baz

Qux

	#include <stdio.h>
	#include <sys/mman.h>
	#include <fcntl.h>
	#include <unistd.h>
	#include <string.h>

	#define STORAGE_ID "/SHM_TEST"
	#define STORAGE_SIZE 32

	int main(int argc, char *argv[])

	--------------------------------------------------------------------------
	# ofed_info -s
	--------------------------------------------------------------------------
	Find Mellanox Adapter Type and Firmware/Driver version
	ConnectX-4 card

	# lspci \| grep Mellanox
	0a:00.0 Network controller: Mellanox Technologies MT27500 Family [ConnectX-3]
	# lspci -vv -s 0a:00.0 \| grep "Part number" -A 3
	# lspci \| grep Mellanox \| awk '{print $1}' \| xargs -i -r mstvpd {}

	sudo apt update && \
	sudo apt install build-essential software-properties-common -y && \
	sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y && \
	sudo apt update && \
	sudo apt install gcc-6 g++-6 -y && \
	sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-6 60 --slave /usr/bin/g++ g++ /usr/bin/g++-6 && \
	gcc -v