get* performance

Hashmaps

Version 5 get* for a hashmap is very similar, even replicating the anomalous dip at 100.

(fn [n] (get (map-of-n-key-vals n) (dec n)))

times in seconds, *mean±std*
version	1	10	100	1000	10000	100000	1000000
	arg, n
4	5.3e-08±6.0e-10	9.2e-08±1.8e-10	1.1e-07±2.0e-09	1.3e-07±2.6e-09	1.4e-07±1.4e-09	1.7e-07±3.6e-09	1.9e-07±3.0e-09
5	5.2e-08±3.0e-10	8.1e-08±3.3e-10	9.3e-08±3.6e-10	1.4e-07±2.1e-09	1.5e-07±1.4e-09	1.6e-07±9.8e-10	1.8e-07±7.2e-10

(fn [n] (get* (map-of-n-key-vals n) (dec n)))

times in seconds, *mean±std*
version	1	10	100	1000	10000	100000	1000000
	arg, n
4	1.0e-07±1.2e-09	2.2e-07±2.1e-09	2.4e-07±1.1e-09	2.6e-07±1.5e-09	2.7e-07±2.8e-09	2.9e-07±2.2e-09	3.2e-07±3.6e-09
5	5.7e-08±2.7e-10	8.5e-08±1.5e-09	9.6e-08±6.4e-10	1.4e-07±5.4e-10	1.5e-07±7.1e-10	1.7e-07±1.0e-09	1.8e-07±8.3e-10

Lists

This benchmark is unfair to get*: clojure.core/get always returns nil when given a list, whereas get* actually retrieves the nth element. The logarithmic behavior is expected for linked lists constructed from the head.

(fn [n] (get (list-of-n-rand-ints n) (dec n)))

times in seconds, *mean±std*
version	1	10	100	1000	10000
	arg, n
4	1.2e-07±8.0e-10	1.4e-07±5.0e-10	1.5e-07±3.5e-10	1.7e-07±2.5e-09	1.8e-07±1.7e-09
5	1.2e-07±4.5e-10	1.4e-07±3.5e-09	1.5e-07±5.0e-10	1.7e-07±1.2e-09	1.8e-07±9.3e-10

(fn [n] (get* (list-of-n-rand-ints n) (dec n)))

times in seconds, *mean±std*
version	1	10	100	1000	10000
	arg, n
4	2.5e-07±8.3e-10	3.1e-07±2.2e-09	6.8e-07±1.1e-09	4.2e-06±2.5e-08	3.9e-05±2.2e-07
5	1.4e-07±1.9e-09	1.9e-07±6.0e-10	5.8e-07±3.2e-09	4.3e-06±2.4e-08	4.2e-05±2.6e-07

Sequences

Version 5 get* very closely provides the performance of clojure.core/nth, a notable improvement from version 4.

(fn [n] (get (seq-of-n-rand-ints n) (dec n)))

times in seconds, *mean±std*
version	1	10	100	1000	10000	100000	1000000
	arg, n
4	3.4e-08±1.8e-10	4.7e-08±2.4e-10	6.2e-08±2.7e-10	7.6e-08±2.7e-10	9.1e-08±7.5e-10	1.0e-07±1.1e-09	1.2e-07±2.3e-09
5	3.6e-08±1.3e-10	5.1e-08±5.0e-10	6.3e-08±1.0e-09	7.6e-08±4.4e-10	8.9e-08±1.5e-09	1.0e-07±5.5e-10	1.1e-07±3.8e-10

(fn [n] (get* (seq-of-n-rand-ints n) (dec n)))

times in seconds, *mean±std*
version	1	10	100	1000	10000	100000	1000000
	arg, n
4	1.7e-07±4.4e-10	1.9e-07±8.9e-10	2.1e-07±9.6e-10	2.2e-07±1.2e-09	2.3e-07±7.2e-10	2.4e-07±2.1e-09	2.5e-07±7.3e-10
5	3.5e-08±1.6e-10	4.6e-08±9.8e-11	5.9e-08±1.3e-10	7.4e-08±1.4e-10	8.6e-08±4.6e-10	9.9e-08±5.1e-10	1.1e-07±5.1e-10

Vectors

Version 5

get* approaches clojure.core/get, being 19% slower for one-element vectors and linearly improving to matching the performance for one-million-element vectors.

(fn [n] (get (vec-of-n-rand-ints n) (dec n)))

times in seconds, *mean±std*
version	1	10	100	1000	10000	100000	1000000
	arg, n
4	3.6e-08±1.1e-10	5.0e-08±7.1e-10	6.4e-08±4.9e-10	7.9e-08±5.1e-10	9.2e-08±2.4e-10	1.1e-07±7.4e-10	1.2e-07±1.5e-09
5	3.6e-08±1.9e-10	4.9e-08±1.4e-10	6.2e-08±2.2e-10	7.5e-08±3.1e-10	8.8e-08±5.6e-10	1.0e-07±7.4e-10	1.2e-07±2.8e-09

(fn [n] (get* (vec-of-n-rand-ints n) (dec n)))

times in seconds, *mean±std*
version	1	10	100	1000	10000	100000	1000000
	arg, n
4	2.0e-07±3.1e-09	2.1e-07±1.4e-09	2.3e-07±1.2e-09	2.5e-07±4.1e-09	2.6e-07±9.3e-10	2.7e-07±3.0e-09	2.9e-07±1.2e-09
5	4.3e-08±2.4e-10	5.7e-08±3.4e-10	6.9e-08±7.7e-10	8.3e-08±2.2e-10	9.5e-08±5.8e-10	1.1e-07±2.4e-10	1.2e-07±8.8e-10