Efficiency and Rock 'n’ Roll (Really!)

Is efficiency rock and roll? You might think the answer is “no, definitely not, no way.” Efficiency is about doing more with less, and rock n’ roll is all about turning it up to eleven and doing more with more. Efficiency is about being responsible, and rock n’ roll is about being irresponsible. But wait! High overheads are not rock n roll, and they’re not efficient. Spending time on boring tasks is neither rock n roll, nor efficient. We’re spending way too much time writing and running code that doesn’t spark joy. In this talk, Holly will discuss practical patterns for wringing maximum value out of our code, for minimum effort. One of the techniques is sleeping! It turns out, both people and computers should be lazier, and that’s definitely rock n roll.

Transcript

1. Holly Cummins Red Hat JNation 2025 Efficiency & Rock ’n’ Roll
2. @hollycummins.com #Quarkus late nights
3. @hollycummins.com #Quarkus late nights
4. @hollycummins.com #Quarkus stimulants
5. @hollycummins.com #Quarkus *@!#f&*%&!
6. @hollycummins.com #Quarkus // wtf
7. @hollycummins.com #Quarkus programming ≈ rock ’n' roll
8. @hollycummins.com #Quarkus programming ≈ rock ’n' roll efficiency rock ’n' roll
9. @hollycummins.com #Quarkus programming ≈ rock ’n' roll efficiency rock ’n' roll?? …
10. @hollycummins.com #Quarkus efficiency achieving the largest amount of useful work using as little energy and effort as possible
11. @hollycummins.com #Quarkus
12. @hollycummins.com #Quarkus rock & roll a style of popular music played on electronically amplified instruments and characterized by a persistent heavily accented beat, repetition of simple phrases …
13. @hollycummins.com #Quarkus rock & roll …
14. @hollycummins.com #Quarkus coolness
15. @hollycummins.com #Quarkus turning it up to 11
16. @hollycummins.com #Quarkus productive
17. @hollycummins.com #Quarkus useful
18. @hollycummins.com #Quarkus excess
19. @hollycummins.com #Quarkus
20. @hollycummins.com #Quarkus minimising waste
21. @hollycummins.com #Quarkus minimising waste
22. @hollycummins.com #Quarkus
23. @hollycummins.com #Quarkus rage against the machine
24. @hollycummins.com #Quarkus rage against the machine
25. @hollycummins.com #Quarkus uh oh.
26. senior principal software engineer quarkus
29. @hollycummins.com #Quarkus
30. @hollycummins.com #Quarkus queueing theory
31. @hollycummins.com #Quarkus queueing theory
32. @hollycummins.com #Quarkus being lazy
33. @hollycummins.com #Quarkus being a rebel
34. @hollycummins.com 1700s machine
35. @hollycummins.com 1700s machine energy
36. @hollycummins.com 1700s machine energy energy
37. @hollycummins.com 1700s machine energy energy useful
38. @hollycummins.com 1700s waste machine energy energy useful
39. @hollycummins.com 1890s processes
40. @hollycummins.com 1890s processes
41. @hollycummins.com time money 1890s processes
42. @hollycummins.com time money 1890s value processes
43. @hollycummins.com time money 1890s value processes waste
44. @hollycummins.com software 1960s
45. @hollycummins.com software time electricity hardware 1960s
46. @hollycummins.com software time electricity hardware answers 1960s
47. @hollycummins.com software time electricity hardware answers 1960s waste
48. @hollycummins.com #Quarkus waste
49. @hollycummins.com #Quarkus 300 years of practice
50. @hollycummins.com #Quarkus “this provisioning software is broken”
51. @hollycummins.com #Quarkus what we sold “this provisioning software is broken” 10 minute provision-time
52. @hollycummins.com #Quarkus what we sold “this provisioning software is broken” 10 minute provision-time 3 month provision- time what the client thought they’d got
53. @hollycummins.com #Quarkus what we sold “this provisioning software is broken” 10 minute provision-time 3 month provision- time what the client thought they’d got the reason 84-step pre-approval process
54. @hollycummins.com
55. @hollycummins.com
56. @hollycummins.com
57. @hollycummins.com
58. @hollycummins.com
59. @hollycummins.com
60. @hollycummins.com doom zoom
61. @hollycummins.com doom zoom landing page
62. @hollycummins.com doom zoom landing page
63. @hollycummins.com doom zoom landing page
64. @hollycummins.com https://blog.linkedin.com/2017/august/3/making-linkedin-more-accessible-via-linkedin-lite Nashik
65. @hollycummins.com https://blog.linkedin.com/2017/august/3/making-linkedin-more-accessible-via-linkedin-lite “my heart sank … our new feature failed to load because of poor internet connectivity” Nashik
66. @hollycummins.com https://blog.linkedin.com/2017/august/3/making-linkedin-more-accessible-via-linkedin-lite modern web is so inefficient it is useless for part of its audience “my heart sank … our new feature failed to load because of poor internet connectivity” Nashik
67. @hollycummins.com code waste is killing the planet
68. @hollycummins.com forgotten code is killing the planet
69. 25% of 16,000 servers doing no useful work https://www.anthesisgroup.com/wp-content/uploads/2019/11/Comatose-Servers-Redux-2017.pdf zombie servers
70. the average server: 12 - 18% of capacity https://www.nrdc.org/sites/default/files/data-center-efficiency-assessment-IB.pdf
71. @hollycummins.com unused data is killing the planet
72. 68% of data is stored and never used https://www.seagate.com/gb/en/news/news-archive/seagates-rethink-data-report-reveals-that-68-percent-of-data-available-to-businesses-goes-unleveraged-pr-master/
73. @hollycummins.com it’s not just money
74. @hollycummins.com it’s not just electricity it’s not just money
75. @hollycummins.com it’s not just electricity it’s not just money it’s embodied carbon
76. @hollycummins.com it’s not just electricity it’s water it’s not just money it’s embodied carbon
77. @hollycummins.com it’s not just electricity it’s water it’s e-waste it’s not just money it’s embodied carbon
78. @hollycummins.com we have solutions good news, everyone
79. @hollycummins.com solution: LightSwitchOps • making turning servers off as safe and easy as turning lights off. • and then automate it.
80. absurdly simple scripts my shell script to power down
81. we used to leave our applications running all the time @darkandnerdy simple automation
82. we used to leave our applications running all the time when we scripted turning them off at night, we reduced our cloud bill by 30% @darkandnerdy simple automation
83. @hollycummins.com #Quarkus fancier scripts … with a frontend and a backend
84. @hollycummins.com #Quarkus why does low utilisation happen?
85. @hollycummins.com #Quarkus why does low utilisation happen? forgetfulness
86. @hollycummins.com #Quarkus apathy why does low utilisation happen? forgetfulness
87. @hollycummins.com #Quarkus apathy why does low utilisation happen? forgetfulness fear
88. @hollycummins.com #Quarkus be a rebel
89. @hollycummins.com #Quarkus be a rebel
90. @hollycummins.com #Quarkus saves energy saves money bonus: tests disaster recovery
91. @hollycummins.com #Quarkus saves energy saves money bonus: tests disaster recovery
92. @hollycummins.com #Quarkus solution: faster code
93. @hollycummins.com the vrroooom model
94. @hollycummins.com
95. @hollycummins.com invented by Dr. Vroom (really!)
96. @hollycummins.com naming is the hardest problem in computer science invented by Dr. Vroom (really!)
97. @hollycummins.com naming is the hardest problem in computer science
98. the wrong kind of rock ’n’ roll
99. the wrong kind of rock ’n’ roll
100. my vrroooom model
102. @hollycummins.com #Quarkus
103. @hollycummins.com #Quarkus these two columns are almost the same
104. @hollycummins.com #Quarkus energy efficiency across programming languages Python Rust Java Go Javascript
105. @hollycummins.com #Quarkus the trend line is more or less straight energy efficiency across programming languages Python Rust Java Go Javascript
107. case study quarkus
108. @hollycummins.com #Quarkus the distant past Java application frameworks needed dynamic dependencies
109. @hollycummins.com #Quarkus cloud apps are immutable now
110. @hollycummins.com #Quarkus cloud apps are immutable now
111. @hollycummins.com #Quarkus cloud apps are immutable now
112. @hollycummins.com #Quarkus cloud apps are immutable now
113. @hollycummins.com #Quarkus cloud apps are immutable now
114. @hollycummins.com #Quarkus cloud apps are immutable now
115. @hollycummins.com #Quarkus a highly dynamic runtime in a container is pointless
116. @hollycummins.com #Quarkus java dynamism
117. @hollycummins.com #Quarkus java dynamism build time
118. @hollycummins.com #Quarkus java dynamism build time runtime
119. @hollycummins.com #Quarkus java dynamism build time runtime
120. @hollycummins.com #Quarkus java dynamism packaging (maven, gradle…) build time runtime
121. @hollycummins.com #Quarkus java dynamism build time runtime
122. @hollycummins.com #Quarkus java dynamism build time runtime
123. @hollycummins.com #Quarkus java dynamism </> build time runtime load and parse • config files • properties • yaml • xml • etc.
124. @hollycummins.com #Quarkus java dynamism </> build time runtime
125. @hollycummins.com #Quarkus java dynamism @ @ </> build time runtime • classpath scanning and annotation discovery • attempt to load class to enable/ disable features
126. @hollycummins.com #Quarkus java dynamism @ @ </> build time runtime
127. @hollycummins.com #Quarkus java dynamism @ @ </> build time runtime build a metamodel of the world
128. @hollycummins.com #Quarkus java dynamism @ @ </> build time runtime
129. @hollycummins.com #Quarkus java dynamism @ @ </> build time runtime start • thread pools • I/O • etc.
130. @hollycummins.com #Quarkus java dynamism @ @ </> build time runtime ready to do work!
131. what if we start the application more than once? @ @ </>
132. what if we start the application more than once? @ @ </> @ @ </>
133. what if we start the application more than once? @ @ </> @ @ </> @ @ </>
134. what if we start the application more than once? @ @ </> @ @ </> @ @ </> @ @ </>
135. what if we start the application more than once? @ @ </> @ @ </> @ @ </> @ @ </> so much work gets redone every time
136. @hollycummins.com Hibernate speed example: JTA auto-wiring
137. @hollycummins.com Hibernate speed example: JTA auto-wiring Class.forName(“LikelyJTAImplementation”);
138. @hollycummins.com Hibernate speed example: JTA auto-wiring Class.forName(“LikelyJTAImplementation”);
139. @hollycummins.com Hibernate speed example: JTA auto-wiring Class.forName(“LikelyJTAImplementation”); Class.forName(“APossibleJTAImplementation”);
140. @hollycummins.com Hibernate speed example: JTA auto-wiring Class.forName(“LikelyJTAImplementation”); Class.forName(“APossibleJTAImplementation”); Class.forName(“AnotherJTAImplementation”);
141. @hollycummins.com Hibernate speed example: JTA auto-wiring Class.forName(“LikelyJTAImplementation”); Class.forName(“APossibleJTAImplementation”); Class.forName(“AnotherJTAImplementation”); Class.forName(“NicheJTAImplementation”); …
142. @hollycummins.com Hibernate speed example: JTA auto-wiring Class.forName(“LikelyJTAImplementation”); Class.forName(“APossibleJTAImplementation”); Class.forName(“AnotherJTAImplementation”); Class.forName(“NicheJTAImplementation”); Class.forName(“VeryNicheJTAImplementation”); …
143. @hollycummins.com Hibernate speed example: JTA auto-wiring Class.forName(“LikelyJTAImplementation”); Class.forName(“APossibleJTAImplementation”); Class.forName(“AnotherJTAImplementation”); Class.forName(“NicheJTAImplementation”); Class.forName(“VeryNicheJTAImplementation”); … ~129 auto-wiring attempts
144. @hollycummins.com Hibernate speed example: JTA auto-wiring Class.forName(“LikelyJTAImplementation”); Class.forName(“APossibleJTAImplementation”); Class.forName(“AnotherJTAImplementation”); Class.forName(“NicheJTAImplementation”); Class.forName(“VeryNicheJTAImplementation”); … ~129 auto-wiring attempts every single start.
145. @hollycummins.com the true cost of loaded classes isn’t just memory + start time
146. @hollycummins.com the true cost of loaded classes isn’t just memory + start time method dispatching:
147. @hollycummins.com interface the true cost of loaded classes isn’t just memory + start time method dispatching:
148. @hollycummins.com unused implementation the one we want interface unused implementation unused implementation the true cost of loaded classes isn’t just memory + start time method dispatching:
149. @hollycummins.com unused implementation the one we want interface unused implementation unused implementation the true cost of loaded classes isn’t just memory + start time method dispatching:
150. @hollycummins.com unused implementation the one we want interface megamorphic call slow dispatching unused implementation unused implementation the true cost of loaded classes isn’t just memory + start time method dispatching:
151. @hollycummins.com the true cost of loaded classes isn’t just memory + start time the one we want interface
152. @hollycummins.com the true cost of loaded classes isn’t just memory + start time the one we want monomorphic call fast dispatching interface
153. @hollycummins.com how do we fix all this?
154. @ @ </> build time runtime what if we initialize at build time?
155. @ @ </> build time runtime what if we initialize at build time?
156. @ @ </> build time runtime ready to do work! what if we initialize at build time?
157. @ @ </> build time runtime ready to do work! start • thread pools • I/O • etc. what if we initialize at build time?
158. @ @ </> repeated starts are now efficient
159. @ @ </> repeated starts are now efficient
160. @ @ </> repeated starts are now efficient
161. @ @ </> repeated starts are now efficient
162. @ @ </> repeated starts are now efficient
163. @ @ </> repeated starts are now efficient
164. @ @ </> repeated starts are now efficient less wasted work
165. @hollycummins.com Setup: • REST + CRUD • large heap • RAPL energy measurement Assumptions: • US energy mix climate impact of framework choice
166. @hollycummins.com Setup: • REST + CRUD • large heap • RAPL energy measurement Assumptions: • US energy mix climate impact of framework choice shorter line means lower max throughput
167. @hollycummins.com Setup: • REST + CRUD • large heap • RAPL energy measurement Assumptions: • US energy mix climate impact of framework choice shorter line means lower max throughput higher line means worse carbon footprint
168. @hollycummins.com Setup: • REST + CRUD • large heap • RAPL energy measurement Assumptions: • US energy mix climate impact of framework choice vrrrooom model in action: quarkus on JVM has the smallest footprint … because it has the highest throughput shorter line means lower max throughput higher line means worse carbon footprint
169. @hollycummins.com throughput startup time + footprint
170. @hollycummins.com we beat the trade-off. throughput startup time + footprint
171. @hollycummins.com we beat the trade-off. throughput startup time + footprint it’s a double-win.
173. @hollycummins.com we beat another trade-off. human efficiency machine efficiency
174. @hollycummins.com we beat another trade-off. human efficiency machine efficiency
175. @hollycummins.com we beat another trade-off. human efficiency machine efficiency another double-win.
176. @hollycummins.com boilerplate code
177. @hollycummins.com live coding
178. @hollycummins.com live coding -less energy wasted running full build + launch cycles
179. @hollycummins.com live coding -less energy wasted running full build + launch cycles -less dev time wasted waiting for full build + launch cycles
180. @hollycummins.com targeted continuous testing
181. @hollycummins.com targeted continuous testing -less energy wasted running full test suites
182. @hollycummins.com targeted continuous testing -less energy wasted running full test suites -less dev time wasted waiting for full test runs
183. @hollycummins.com #Quarkus developer joy
184. @hollycummins.com #Quarkus is a double win developer joy
185. @hollycummins.com #Quarkus the double win isn’t just a java thing.
186. @hollycummins.com #Quarkus the ai-lephant in the room
187. @hollycummins.com #Quarkus does developer efficiency even matter?
188. @hollycummins.com
189. @hollycummins.com
190. @hollycummins.com
191. @hollycummins.com
192. @hollycummins.com
193. @hollycummins.com
194. @hollycummins.com 70% unnecessary code
195. @hollycummins.com
196. @hollycummins.com we spend far more time reading code than writing it
197. @hollycummins.com shifting the work to future-you
198. @hollycummins.com illusion of efficiency
199. @hollycummins.com #Quarkus illusions of efficiency are everywhere
200. @hollycummins.com
201. @hollycummins.com
202. @hollycummins.com
203. @hollycummins.com even for machines, there is a limit to efficiency
204. @hollycummins.com source: http://geosci.uchicago.edu/~moyer/GEOS24705/2016/Assignments/PS7.pdf
205. @hollycummins.com thermodynamics source: http://geosci.uchicago.edu/~moyer/GEOS24705/2016/Assignments/PS7.pdf
206. @hollycummins.com
207. @hollycummins.com
208. @hollycummins.com theoretical max efficiency of a combustion engine
209. @hollycummins.com theoretical max efficiency of a combustion engine 37%
210. @hollycummins.com typical efficiency of a combustion engine
211. @hollycummins.com ~20% typical efficiency of a combustion engine
212. @hollycummins.com it’s detuned so the engine does not wear out ~20% typical efficiency of a combustion engine
213. @hollycummins.com it’s detuned so the engine does not wear out ~20% typical efficiency of a combustion engine
214. @hollycummins.com
215. @hollycummins.com highly efficient (optimum number of legs)
216. @hollycummins.com highly efficient (optimum number of legs) less efficient (more legs than needed)
217. @hollycummins.com highly efficient (optimum number of legs) less efficient (more legs than needed) resilient
218. @hollycummins.com highly efficient (optimum number of legs) less efficient (more legs than needed) resilient
219. @hollycummins.com highly efficient (optimum number of legs) no resiliency less efficient (more legs than needed) resilient
220. @hollycummins.com highly efficient (optimum number of legs) no resiliency less efficient (more legs than needed) resilient resiliency lowers efficiency
221. @hollycummins.com
222. @hollycummins.com speed
223. @hollycummins.com speed vs resiliency
224. @hollycummins.com it’s the same for people
225. @hollycummins.com it’s the same for people all work and no play is … not efficient
226. @hollycummins.com
227. @hollycummins.com hi colleague, could you ple-
228. @hollycummins.com hi colleague, could you ple- argh! &!*$*%@!{*%^!^! busy! NO! I CANNOT!
229. @hollycummins.com #Quarkus the value of slack
230. @hollycummins.com #Quarkus the value of slack
231. @hollycummins.com #Quarkus the value of slack
232. @hollycummins.com #Quarkus the value of slack
233. @hollycummins.com #Quarkus the value of slack naming is still the hardest problem in computer science
234. @hollycummins.com #Quarkus
235. @holly_cummins #RedHat doing nothing
236. @holly_cummins #RedHat doing nothing efficiency
237. @holly_cummins #RedHat the default mode network idle minds can solve hard problems
238. #RedHat @holly_cummins
239. @hollycummins.com #Quarkus
240. @hollycummins.com #Quarkus
241. @hollycummins.com #Quarkus 14% took showers specifically for the purpose of coming up with ideas
242. @hollycummins.com psychology says we need idle time; maths agrees
243. @hollycummins.com queueing theory says systems need to run under-capacity to function psychology says we need idle time; maths agrees
244. @hollycummins.com queuing theory basics queue arrival process servers completed work
245. @hollycummins.com queuing theory basics queue arrival process servers completed work
246. @hollycummins.com queuing theory basics Poisson distribution queue arrival process servers completed work
247. @hollycummins.com queuing theory basics Poisson distribution queue arrival process servers completed work
248. @hollycummins.com queuing theory basics Poisson distribution queue arrival process servers completed work
249. @hollycummins.com queuing theory basics Poisson distribution queue arrival process servers completed work
250. @hollycummins.com queuing theory basics Poisson distribution queue arrival process servers completed work
251. @hollycummins.com queuing theory basics Poisson distribution queue arrival process servers completed work
252. @hollycummins.com if arrival rates are low, servers will be idle queue arrival process servers completed work
253. @hollycummins.com if server capacity is too low, wait times are high queue arrival process servers completed work
254. @hollycummins.com utilisation lead time http://brodzinski.com/2015/01/slack-time-value.html assuming Poisson distribution of arrivals
255. @hollycummins.com utilisation lead time http://brodzinski.com/2015/01/slack-time-value.html assuming Poisson distribution of arrivals 80% utilisation → 90% utilisation: wait times double
256. @hollycummins.com utilisation http://brodzinski.com/2015/01/slack-time-value.html cost delay cost assuming Poisson distribution of arrivals 80% utilisation → 90% utilisation: wait times double
257. @hollycummins.com utilisation http://brodzinski.com/2015/01/slack-time-value.html cost delay cost cost of idle capacity assuming Poisson distribution of arrivals 80% utilisation → 90% utilisation: wait times double
258. @hollycummins.com the 6-day working week was the standard
259. @hollycummins.com the 6-day working week
260. @hollycummins.com
261. @hollycummins.com productivity stayed the same
262. @hollycummins.com
263. @hollycummins.com the 4-day working week?
264. @hollycummins.com 42% decrease in resignations the 4-day working week?
265. @hollycummins.com 42% decrease in resignations 36% increase in revenue the 4-day working week?
266. @hollycummins.com jevon’s paradox limit 1: economic theory
267. @hollycummins.com jevon’s paradox limit 1: economic theory “efficiency improvements can lead to increased consumption”
268. what we imagine when we widen roads
269. @hollycummins.com what we get
270. @hollycummins.com inverse Jevon’s manoeuvre doing less achieves more
271. @hollycummins.com the trade-off isn’t what we think it is being effective working less
272. @hollycummins.com the trade-off isn’t what we think it is being effective working less
273. @hollycummins.com the trade-off isn’t what we think it is being effective working less another double-win.
274. @hollycummins.com #Quarkus the most inefficient thing I’ve ever done
275. @hollycummins.com #Quarkus
276. @hollycummins.com #Quarkus
277. @hollycummins.com #Quarkus
278. @hollycummins.com #Quarkus “I did not know what Rockstar was before I went to this talk. I do not think I will use Rockstar at work.”
279. play
280. @hollycummins.com tl;dpa (too long; didn’t pay attention)
281. @hollycummins.com tl;dpa ⁃ rage against waste; our world deserves better (too long; didn’t pay attention)
282. @hollycummins.com tl;dpa ⁃ rage against waste; our world deserves better ⁃ work less; achieve more (too long; didn’t pay attention)
283. @hollycummins.com tl;dpa ⁃ rage against waste; our world deserves better ⁃ work less; achieve more ⁃ happiness is not waste (too long; didn’t pay attention)
284. @hollycummins.com tl;dpa ⁃ rage against waste; our world deserves better ⁃ work less; achieve more ⁃ happiness is not waste ⁃ idleness is not waste (too long; didn’t pay attention)
285. @hollycummins.com tl;dpa ⁃ rage against waste; our world deserves better ⁃ work less; achieve more ⁃ happiness is not waste ⁃ idleness is not waste ⁃ look for double-wins everywhere (too long; didn’t pay attention)
286. @hollycummins.com https://hollycummins.com/efficiency-rocknroll/