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  1. General Background and Overview

Quick Tips for Fast Code on the JVM

I was talking to a coworker recently about general techniques that almost always form the core of any effort to write very fast, down-to-the-metal hot path code on the JVM, and they pointed out that there really isn't a particularly good place to go for this information. It occurred to me that, really, I had more or less picked up all of it by word of mouth and experience, and there just aren't any good reference sources on the topic. So… here's my word of mouth.

This is by no means a comprehensive gist. It's also important to understand that the techniques that I outline in here are not 100% absolute either. Performance on the JVM is an incredibly complicated subject, and while there are rules that almost always hold true, the "almost" remains very salient. Also, for many or even most applications, there will be other techniques that I'm not mentioning which will have a greater impact. JMH, Java Flight Recorder, and a good profiler are your very best friend! Mea

@j-keck
j-keck / aws-sqs.policy
Created October 1, 2020 14:29 — forked from marcelog/aws-sqs.policy
SQS Policy to allow an S3 bucket to publish messages
{
"Version": "2012-10-17",
"Id": "arn:aws:sqs:YOUR-AWS-REGION:YOUR-AWS-ACCOUNT-ID:YOUR-QUEUE-NAME/SQSDefaultPolicy",
"Statement": [
{
"Sid": "example-statement-ID",
"Effect": "Allow",
"Principal": {
"AWS": "*"
},
@j-keck
j-keck / aws-sqs.policy
Created October 1, 2020 14:29 — forked from marcelog/aws-sqs.policy
SQS Policy to allow an S3 bucket to publish messages
{
"Version": "2012-10-17",
"Id": "arn:aws:sqs:YOUR-AWS-REGION:YOUR-AWS-ACCOUNT-ID:YOUR-QUEUE-NAME/SQSDefaultPolicy",
"Statement": [
{
"Sid": "example-statement-ID",
"Effect": "Allow",
"Principal": {
"AWS": "*"
},
@j-keck
j-keck / angular-install.sh
Created December 16, 2020 08:31 — forked from StephenFluin/angular-install.sh
Install Angular on a *nix system
# NVM
curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.11/install.sh | bash
export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh" # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion" # This loads nvm bash_completion
nvm install 10
# Yarn
curl -o- -L https://yarnpkg.com/install.sh | bash
export PATH="$HOME/.yarn/bin:$HOME/.config/yarn/global/node_modules/.bin:$PATH"
@j-keck
j-keck / readme.md
Created February 7, 2021 08:53 — forked from rometsch/BH456A_linux_driver.md
MPOW BH456A Bluetooth USB Adapter Kernel Module Adjustements (Realtek RTL8761B chip)

Problem

The MPOW Bluetooth 5 dongle (Model: BH456A) does not work out of the box on Ubuntu 20.04 (kernel 5.4.0-42).

Solution

Patch the bluetooth kernel module and copy the firmware binaries to /lib/firmware.

Copy the fimware