Gaurav Singh sgaurav

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

	app.post('/webhook/', receiveMessage);

	function receiveMessage(req, res, next){
	var message_instances = req.body.entry[0].messaging;
	message_instances.forEach(function(instance){
	var sender = instance.sender.id;
	if(instance.message && instance.message.text) {
	fetchUserProfileAndReply(sender, conf.PROFILE_TOKEN);
	}
	});