OPTIMIZE

This page describes optimization tasks.

general:
	scripts for performance and stability testing
	testing optimizations (-O2)
	profile the code and fix optimization leaks
	benchmark first!


== mmap storage ==

Implement as global plugins

Cow: key/keyset for mmap storage [in progress]
	allocate everything in keyNew in a single block
	then for value/name changes, do malloc/realloc (COW)

Mmap global plugin:
	in the get path: resolver-like functionality to check if
		mmap files are up-to-date, if they are immediately
		return mmaped KeySet
	at the end of get path: store everything so that it can
		be mmaped the next time
	sanity checks for byte order, version, validity...


== lazyness ==

make KeySet lazy (create keys on ksLookup)
make getValue lazy (fetch value on ksLookup)
	feature interferes with mmap storage and
	might be even slower than mmap

== SEARCH ==

profiler:
	search for slow parts

elektraMalloc trace:
	reduce elektraMallocs

keySet:
	make statistics how many keys typical applications need
	be efficient for typical needs

== metadata ==

Because metadata is often the same across many keys we introduced a way to share it.
heap profiling of a large keyset with/without shared metadata

examine "benchmark" again, maybe some more interesting things are hidden there...

== EXCEPTION ==

do not throw exceptions within checker plugins (or fix benchmark)


== OPTIMIZE ==

Key unchanged always checked correctly?

check if anything was really changed making key dirty

optimize a key to use a single elektraMalloc
	(under typical circumstances)
	have all memory of a Key in a single allocation block
	or use internally memory management which can be in mmap?
	-> especially useful for keyNew

dynamic memory management:
	improve realloc, use srealloc
	don't use sprintf, asprintf, strdup, strndup
	use only own functions where available
	use different compilers, libc too

ksAppend() in O(1)

iconv:
	open handles in kdbOpen? (depending on kdbOpen optimization that it is only done when needed)


== OTHER ==

getString in C++



== BENCHMARK TESTS ==

iteration
multiple type checkers overhead?
insertion (dump::serialise)
null ptr checks
many mountpoints
many globbing statements

== DATA STRUCTURES ==

improve memory footprint C structures:
	https://www.catb.org/esr/structure-packing/?src=yc