We'll start on threads early

Multicore CPUs
	Seems simple:  Just put a bunch of CPU dies together	
	EPYC page:  https://en.wikipedia.org/wiki/Epyc
	Cache:
	L1:  Specific to a core
	L2:  Shared between cores maybe
		ChatGPT thought so
		AMD 9000 series has per-core L2
	L3:  More shared
	So...each thread should have its own registers
		And stack?
		Where are their stacks?
		Can a thread access another thread's stack?
		Do they have the same heap?
			Can a thread allocate something and another thread free it?
		What happens if one thread calls exit?
		Do they really run at the same time at nanosecond precision?
			clock_gettime
	Let's see if we can answer all these questions!	

pthreads library:
	Allows us to run our program from more than one place at once

Simple example:
	pthread_create
	Just make it do two things at once
	C or C++?
		For this example, cout is about all that's different

Speedup:
	Could be questionable!
	Depends on the task

Race Conditions:
	Something that varies based on timing
	We can engineer one easy enough
		Use random and usleep maybe?
		Remember to seed it

Preventing race conditions:  A mutex
	Mutual Exclusion
	There are other things here (atomic operations, etc) but mutex is enough for now

Project 5:
	This should speed up ok
	Too many threads might get in the way, depending on how you do it

A sample problem:
	I did image filters last time