Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Site-Speed That Sticks
Search
Harry Roberts
November 14, 2024
Technology
3
370
Site-Speed That Sticks
Harry Roberts
November 14, 2024
Tweet
Share
More Decks by Harry Roberts
See All by Harry Roberts
How to Think Like a Performance Engineer
csswizardry
22
1.3k
cache rules everything
csswizardry
3
3.1k
My Website Is Slow! Where Do I Start?
csswizardry
5
430
Optimising Largest Contentful Paint
csswizardry
34
3.1k
Get Your Head Straight
csswizardry
15
19k
From Milliseconds to Millions: A Look at the Numbers Powering Web Performance
csswizardry
1
2.4k
More Than You Ever Wanted to Know About Resource Hints
csswizardry
6
9.1k
It’s My (Third) Party, and I’ll Cry if I Want To
csswizardry
13
5.4k
FaCSSt: CSS & Performance
csswizardry
26
4k
Other Decks in Technology
See All in Technology
データ資産をシームレスに伝達するためのイベント駆動型アーキテクチャ
kakehashi
PRO
2
470
急成長する企業で作った、エンジニアが輝ける制度/ 20250214 Rinto Ikenoue
shift_evolve
2
1.1k
個人開発から公式機能へ: PlaywrightとRailsをつなげた3年の軌跡
yusukeiwaki
11
2.9k
Tech Blogを書きやすい環境づくり
lycorptech_jp
PRO
1
230
Oracle Base Database Service 技術詳細
oracle4engineer
PRO
6
57k
技術負債の「予兆検知」と「状況異変」のススメ / Technology Dept
i35_267
1
1k
『衛星データ利用の方々にとって近いようで触れる機会のなさそうな小話 ~ 衛星搭載ソフトウェアと衛星運用ソフトウェア (実物) を動かしながらわいわいする編 ~』 @日本衛星データコミニティ勉強会
meltingrabbit
0
140
地方拠点で エンジニアリングマネージャーってできるの? 〜地方という制約を楽しむオーナーシップとコミュニティ作り〜
1coin
1
220
Helm , Kustomize に代わる !? 次世代 k8s パッケージマネージャー Glasskube 入門 / glasskube-entry
parupappa2929
0
210
リーダブルテストコード 〜メンテナンスしやすい テストコードを作成する方法を考える〜 #DevSumi #DevSumiB / Readable test code
nihonbuson
11
6.8k
データマネジメントのトレードオフに立ち向かう
ikkimiyazaki
3
300
Amazon S3 Tablesと外部分析基盤連携について / Amazon S3 Tables and External Data Analytics Platform
nttcom
0
120
Featured
See All Featured
Keith and Marios Guide to Fast Websites
keithpitt
411
22k
CSS Pre-Processors: Stylus, Less & Sass
bermonpainter
356
29k
What's in a price? How to price your products and services
michaelherold
244
12k
Improving Core Web Vitals using Speculation Rules API
sergeychernyshev
9
430
Designing Dashboards & Data Visualisations in Web Apps
destraynor
231
53k
ReactJS: Keep Simple. Everything can be a component!
pedronauck
666
120k
10 Git Anti Patterns You Should be Aware of
lemiorhan
PRO
656
59k
How To Stay Up To Date on Web Technology
chriscoyier
790
250k
Done Done
chrislema
182
16k
Statistics for Hackers
jakevdp
797
220k
A Tale of Four Properties
chriscoyier
158
23k
The Pragmatic Product Professional
lauravandoore
32
6.4k
Transcript
site-speed that sticks
None
hi, i’m harry
None
five key topics
1. metrics 2. localhost 3. backstops 4. monitoring 5. playbook
1. metrics 2. localhost 3. backstops 4. monitoring 5. playbook
1. metrics 2. localhost 3. backstops 4. monitoring 5. playbook
1. metrics 2. localhost 3. backstops 4. monitoring 5. playbook
1. metrics 2. localhost 3. backstops 4. monitoring 5. playbook
1. metrics 2. localhost 3. backstops 4. monitoring 5. playbook
metrics
not all metrics are born equal
different metrics for different people on different occasions with different
levels of disclosure
kpis, enablers, predictors
kpis
definition + target
what are we working toward?
of interest to the business
core web vitals
‘which number on which dashboard of which service?’
“We want a one-second improvement in Largest Contentful Paint.” —
My Client
None
None
None
enablers
metrics that directly influence kpis
of interest to engineering teams
ttfb, input delay
predictors
signals of good/bad performance
highly quantitative
of interest to engineers
bundle size, long tasks, blocking css
great for root-causing and reverse engineering
localhost
localhost is: seldom live-like, pretty dang fast, un-bundled
know your tools inside out
None
None
csswz.it/perfnow25
one weird trick…
None
// plugins/delay.server.ts export default defineNuxtPlugin(async () => { await new
Promise(resolve => setTimeout(resolve, 900)) })
None
None
<head> <link rel=stylesheet href=https://slowfil.es/file?type=css&delay=800> </head>
core web vitals are too big for localhost
if you’re working locally, measure locally
bare-metal metrics
None
None
1
1 2
1 2 3
1 2 3
None
None
1
1 2
1 2 3
1 2 3
external: 1842ms inlined: 1250ms
None
these are very private metrics
backstops
…and budgets
what is the worst possible performance we will accept?
set it to the worst reading in the last release
cycle
None
this is where synthetic testing comes into it
synthetic testing; real user monitoring
when to fail a release
None
predictors as tripwires
None
budgets versus targets
budgets are backstops; targets are ambitions
target == kpi
None
monitoring
the m in rum stands for monitoring
“Insanity is doing the same thing over and over again
and expecting different results.” — Rita Mae Brown
None
🎉
?
None
None
None
None
it’s the exact same file
None
you’re monitoring variation in tests
None
only alert on your kpis
None
None
0.9952409649
None
None
always follow the numbers
playbook
“Fighting regressions took priority over optimizations […]” — Michelle Vu,
Pinterest
None
it’s all for nothing if you don’t have a plan
response = f(severity, duration)
severity
acceptable: <10%
moderate: 10–25%
severe: 25–50%
critical: >50%
duration
temporary: 24–48hr
sustained: >48hr
long-term: >1 release cycle
unresolved: many release cycles
a kpi regression of over 10% for one week requires
remediation in the next sprint
a kpi regression of over 100% for one hour requires
rollback immediately
a kpi regression of over 25% for one day requires
remediation in the current sprint
an enabler regression of over any% for any time needs
the team’s attention over the next sprint
a predictor regression of over any% for any time needs
my attention over the next sprint
you need a framework to fill in these blanks
early triage
who, what, when, where, and why?
what?
what has regressed?
when?
when did it start? is it still like that?
where?
is it a business-critical part of the site?
who?
who owns the problem?
why?
can you conduct early triage?
None
None
None
None
None
None
key takeaways
increase confidence
use the right tool for the right job
have a plan of attack
agree; commit
thank you
harry.is/for-hire