pankkor

“There are no solutions. There are only trade-offs.” ― Thomas Sowel

TL;DR:

Writing code is craft. Master your craft.
Keep it simple.
Writing simple code is hard.
Simple code is rarely celebrated as an achievement. Folks worship meta-programming when old school macro can do the trick.
Code is liability. Prefer removing code over adding it. Strongly prefer removing code in big codebases.
Complexity kills. Kills UX, development times, quality, costs, debugability, comprehensibility.

Installation

sudo apt install linux-tools-common

Setup

To be able to grab performance and kernel events. Lower sampling rate to 10000, if it takes too much time. If it happens kernel will automatically lower perf_event_max_sample_rate. Examine dmesg output for perf: interrupt took too long, lowering kernel.perf_event_max_sample_rate to value.

sudo dmesg -wH | grep perf:

Reduce performance variance of benchmarks

Linux

Set/Reset the CPU governor

cpupower frequency-info -o proc
sudo cpupower frequency-set --governor performance

Disable CPU boosting

Perf: Profiling on machine A and investigating on machine B

Perf setup

Apt (Debian, Ubuntu)

On newer systems:

sudo apt install linux_perf

On older systems:

macOS input monitoring aka spyware.

Inspect UI elements under the mouse.

Examples

UIElementInspector sample from 2010

https://developer.apple.com/library/archive/samplecode/UIElementInspector/Introduction/Intro.html Provides information of AXUIElements under the cursor via Accessibility API introduced in Mac OS X version 10.2.

Acessibility Inspector

Snippets

Quickly limit resources for the process with `ulimit`

LIMIT_MB=50
(ulimit -Sv $((LIMIT_MB << 10)); /path/to/binary)

On OpenBSD use

Linux Perf Tools

Materials used to write this gist.

TL;DR

uptime

	#!/bin/sh
	help="
	Monitor specific process tree hierarchy.
	Pass case instensitive name of a process as a first argument.

	USAGE:
	./psmon.sh [proccess_name]
	"

	if [ $# -lt 1 ]; then

	#!/bin/sh

	help="Reduce performance variance of the system.

	OPTIONS:
	-h, --help This help.
	* ANY other argument reverts the changes.
	"

	case "$1" in

	FORCE_INLINE static f32 absf32(f32 v) {
	f32 ret;
	__asm__ volatile (
	"fabs %s0, %s1\n"
	: "=w" (ret)
	: "w" (v)
	);
	return ret;
	}