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6 ½ ridiculous
things to do
with Quarkus
Holly Cummins
IBM
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No content
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quarkus is used in
production by:
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quarkus is used in
production by:
• telcos
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quarkus is used in
production by:
• telcos
• retailers
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quarkus is used in
production by:
• telcos
• retailers
• banks
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quarkus is used in
production by:
• telcos
• retailers
• banks
BORING!
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1
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https://github.com/holly-cummins/gen-alpha-iser
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was this an easy demo?
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was this an easy demo?
super easy
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tell your
boss you
learned… @ServerResponseFilter
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2
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https://github.com/phillip-kruger/quarkus-jokes
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was this an easy demo?
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was this an easy demo?
yes, phillip krüger
wrote all of it :)
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tell your
boss you
learned…
the dev ui now has
assistants to help you
write + debug code
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No content
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No content
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No content
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No content
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No content
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No content
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3
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https://github.com/quarkiverse/quarkus-bon-jova-rockstar
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https://github.com/quarkiverse/quarkus-bon-jova-rockstar
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was this an easy demo?
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was this an easy demo?
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was this an easy demo?
-friends don’t let friends
write compilers
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was this an easy demo?
-friends don’t let friends
write compilers
-bytecode generation :(
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was this an easy demo?
-friends don’t let friends
write compilers
-bytecode generation :(
-parsing :( :(
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tell your
boss you
learned…
-the quarkiverse is very
welcoming to new
extensions
-writing a compiler is a bad
idea (but if you do go
there, use antlr)
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No content
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No content
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spec
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spec
(by dylan beattie)
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spec
(by dylan beattie)
cost: 5 beers + 1 napkin
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spec
(by dylan beattie)
cost: 5 beers + 1 napkin
time: 1 night
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spec
spec
(by dylan beattie)
cost: 5 beers + 1 napkin
time: 1 night
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spec
none, obvs
spec
(by dylan beattie)
cost: 5 beers + 1 napkin
time: 1 night
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spec
none, obvs
spec
(by dylan beattie)
cost: 5 beers + 1 napkin
time: 1 night
implementation
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spec
none, obvs
spec
(by dylan beattie)
cost: 5 beers + 1 napkin
time: 1 night
implementation
cost: $0
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spec
none, obvs
spec
(by dylan beattie)
cost: 5 beers + 1 napkin
time: 1 night
implementation
cost: $0
time: 3 weeks
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spec
none, obvs
spec
(by dylan beattie)
cost: 5 beers + 1 napkin
time: 1 night
implementation
cost: $0
time: 3 weeks
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spec
none, obvs
implementation
spec
(by dylan beattie)
cost: 5 beers + 1 napkin
time: 1 night
implementation
cost: $0
time: 3 weeks
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spec
none, obvs
implementation
cost: $36,312.03
spec
(by dylan beattie)
cost: 5 beers + 1 napkin
time: 1 night
implementation
cost: $0
time: 3 weeks
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spec
none, obvs
implementation
cost: $36,312.03
time: 3 months
spec
(by dylan beattie)
cost: 5 beers + 1 napkin
time: 1 night
implementation
cost: $0
time: 3 weeks
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gen ai: what
could possibly
go wrong?
4
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No content
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https://www.computerworld.com/article/4059383/openai-admits-ai-hallucinations-are-mathematically-inevitable-not-just-engineering-flaws.html
rate of hallucination when summarizing
public information:
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o1: 16%
https://www.computerworld.com/article/4059383/openai-admits-ai-hallucinations-are-mathematically-inevitable-not-just-engineering-flaws.html
rate of hallucination when summarizing
public information:
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o1: 16%
o3: 33%
https://www.computerworld.com/article/4059383/openai-admits-ai-hallucinations-are-mathematically-inevitable-not-just-engineering-flaws.html
rate of hallucination when summarizing
public information:
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o1: 16%
o3: 33%
o4-mini: 48%
https://www.computerworld.com/article/4059383/openai-admits-ai-hallucinations-are-mathematically-inevitable-not-just-engineering-flaws.html
rate of hallucination when summarizing
public information:
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solution: guardrails
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“LLM-as-a-judge”
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“LLM-as-a-judge”
BORING!
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No content
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was this an easy demo?
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was this an easy demo?
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was this an easy demo?
-adding guardrails is simple
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was this an easy demo?
-adding guardrails is simple
-but … the demo needed
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was this an easy demo?
-adding guardrails is simple
-but … the demo needed
-a prompt the llm would
hallucinate about 50% of the
time
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was this an easy demo?
-adding guardrails is simple
-but … the demo needed
-a prompt the llm would
hallucinate about 50% of the
time
-a reliable guardrail
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tell your
boss you
learned…
-guardrails are important
- llm-as-a-judge is still an llm
-manage context wiseley
- context cruft lowers response
quality
- context growth can cause
problems
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observability
5
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No content
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user code
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user code
quarkus
framework
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application
user code
quarkus
framework
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application
user code
quarkus
framework
extensions
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application
user code
quarkus
framework
extensions
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application
user code
quarkus
framework
client
extensions
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application
user code
quarkus
framework
client
extensions
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application
user code
quarkus
framework
client
extensions
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application
user code
quarkus
framework
client
extensions
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application
user code
quarkus
framework
client
extensions
observability stack
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application
user code
quarkus
framework
client
metrics
extensions
observability stack
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application
user code
quarkus
framework
client
metrics
traces
extensions
observability stack
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application
user code
quarkus
framework
client
metrics
traces
logs
extensions
observability stack
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application
user code
quarkus
framework
observability
client
client
metrics
traces
logs
extensions
observability stack
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application
user code
quarkus
framework
observability
client
client
metrics
traces
logs
extensions
observability stack
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application
user code
quarkus
framework
observability
client
client
dev service
(testcontainers)
extensions
observability stack
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application
user code
quarkus
framework
observability
client
client
dev service
(testcontainers)
extensions
observability stack
BORING!
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application
user code
quarkus
framework
client
extensions
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application
user code
quarkus
framework
client
extensions
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application
user code
quarkus
framework
client
extensions
minecraft server
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application
user code
quarkus
framework
minecraft
client
client
extensions
minecraft server
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application
user code
quarkus
framework
minecraft
client
client
extensions
minecraft server
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application
user code
quarkus
framework
minecraft
client
client
extensions
minecraft server
mod
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application
user code
quarkus
framework
minecraft
client
client
dev service
(testcontainers)
extensions
minecraft server
mod
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No content
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https://github.com/quarkiverse/quarkus-observability-minecraft
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No content
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tell your
boss you
learned…
-you can do a lot
with interceptors
-dev services are
awesome
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No content
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https://github.com/quarkiverse/quarkus-observability-minecraft
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https://github.com/quarkiverse/quarkus-observability-minecraft
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was this an easy demo?
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was this an easy demo?
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was this an easy demo?
-extension was easy, minecraft
mod was hard
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was this an easy demo?
-extension was easy, minecraft
mod was hard
-minecraft APIs
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was this an easy demo?
-extension was easy, minecraft
mod was hard
-minecraft APIs
-lack documentation
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was this an easy demo?
-extension was easy, minecraft
mod was hard
-minecraft APIs
-lack documentation
-change between minor versions
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was this an easy demo?
-extension was easy, minecraft
mod was hard
-minecraft APIs
-lack documentation
-change between minor versions
-client-server sync of injected
behaviour is hard
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tell your
boss you
learned…
-typesafe objects are
better than a chat box
-… but small models may
struggle with structured
data
-gen ai adds latency
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how quick can
quarkus go?
6
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No content
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thanks to markus
eisele for the
graphics code
https://github.com/holly-cummins/meme-generator
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was this an easy demo?
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was this an easy demo?
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was this an easy demo?
-writing the cli was easy
-native compilation
was easy
-native compilation +
awt + mac is very hard
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No content
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i tried:
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i tried:
native awt on mac
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i tried:
native awt on mac
liberica vm mac + tuning of
build-time and runtime classes
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i tried:
native awt on mac
liberica vm mac + tuning of
build-time and runtime classes
graalvm community container
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i tried:
native awt on mac
liberica vm mac + tuning of
build-time and runtime classes
graalvm community container
mandrel container
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tell your
boss you
learned…
•picocli + quarkus is cool
•native is clever tech
•…but native has dragons
•only go native if you
actually need it
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is quarkus fast?
(again)
6½
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No content
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was this an easy demo?
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was this an easy demo?
eric deandrea wrote
the initial app and
julien ponge wrote
the scripts
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was this an easy demo?
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was this an easy demo?
writing benchmarks
is trivial … but writing
good benchmarks
is hard
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https://github.com/quarkusio/spring-quarkus-perf-comparison
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don’t do perf testing on a laptop
don’t drive load from the machine being measured
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here’s what
we see in our
controlled lab
https://github.com/edeandrea/quarkus-for-spring-devs-examples/tree/quarkus-for-spring-devs-talk-sb3
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here’s what
we see in our
controlled lab
https://github.com/edeandrea/quarkus-for-spring-devs-examples/tree/quarkus-for-spring-devs-talk-sb3
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here’s what
we see in our
controlled lab
https://github.com/edeandrea/quarkus-for-spring-devs-examples/tree/quarkus-for-spring-devs-talk-sb3
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here’s what
we see in our
controlled lab
https://github.com/edeandrea/quarkus-for-spring-devs-examples/tree/quarkus-for-spring-devs-talk-sb3
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it’s not really about speed
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it’s not really about throughput
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it’s about hardware
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… and hardware is money
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No content
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spring boot quarkus
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spring boot quarkus
40 586 req/s
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spring boot quarkus
40 586 req/s
17 209 req/s
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spring boot quarkus
40 586 req/s
17 209 req/s
1 342 errors
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spring boot quarkus
40 586 req/s
17 209 req/s
1 342 errors
2 vCPUs
0.5 GiB
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spring boot quarkus
t3.nano
$0.0052
40 586 req/s
17 209 req/s
1 342 errors
2 vCPUs
0.5 GiB
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spring boot quarkus
t3.nano
$0.0052
40 586 req/s
17 209 req/s
1 342 errors
2 vCPUs
2 GiB
2 vCPUs
0.5 GiB
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spring boot quarkus
t3.nano
$0.0052
t3.small
$0.0208
40 586 req/s
17 209 req/s
1 342 errors
2 vCPUs
2 GiB
2 vCPUs
0.5 GiB
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spring boot quarkus
t3.nano
$0.0052
t3.small
$0.0208
40 586 req/s
17 209 req/s
1 342 errors
$3.87 a month
2 vCPUs
2 GiB
2 vCPUs
0.5 GiB
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spring boot quarkus
t3.nano
$0.0052
t3.small
$0.0208
40 586 req/s
17 209 req/s
1 342 errors
$15.47 a month
$3.87 a month
2 vCPUs
2 GiB
2 vCPUs
0.5 GiB
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spring boot quarkus
t3.nano
$0.0052
t3.small
$0.0208
40 586 req/s
17 209 req/s
1 342 errors
$15.47 a month
$3.87 a month
x2
2 vCPUs
2 GiB
2 vCPUs
0.5 GiB
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spring boot quarkus
t3.nano
$0.0052
t3.small
$0.0208
40 586 req/s
17 209 req/s
1 342 errors
$15.47 a month
$3.87 a month
$30.94 a month
x2
2 vCPUs
2 GiB
2 vCPUs
0.5 GiB
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spring boot quarkus
t3.nano
$0.0052
t3.small
$0.0208
40 586 req/s
17 209 req/s
1 342 errors
$15.47 a month
$3.87 a month
$30.94 a month
x2
2 vCPUs
2 GiB
2 vCPUs
0.5 GiB
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spring boot quarkus
t3.nano
$0.0052
t3.small
$0.0208
40 586 req/s
17 209 req/s
1 342 errors
$15.47 a month
$3.87 a month
$30.94 a month
x2
2 vCPUs
2 GiB
2 vCPUs
0.5 GiB
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tell your
boss you
learned…
-quarkus uses 2 - 8x fewer
compute resources than
spring
-quarkus is 2 - 8x cheaper
to run than spring
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it’s also about energy
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it’s also about energy
BORING!
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No content
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No content
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No content
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No content
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9000
potatoes
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No content
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0.0007 W
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t3.nano t3.small 2x t3.small
Watts per
hour
12.5 14 28
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t3.nano t3.small 2x t3.small
Watts per
hour
12.5 14 28
Lemons per
hour
17,857 20,000 40,000
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spring boot
40,000 lemons/hour
quarkus
17,857 lemons/hour
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No content
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jbang wrk2@hyperfoil -t2 -c100 -d30s -R 200 --latency http://
localhost:8080/fruits
jbang wrk@hyperfoil -t2 -c100 -d20s --timeout 1s http://
localhost:8080/fruits
sudo powermetrics --samplers cpu_power,tasks --show-process-
samp-norm --show-process-gpu --show-usage-summary -i 0 -o
output.txt
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https://github.com/quarkusio/spring-quarkus-perf-comparison
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https://github.com/quarkusio/spring-quarkus-perf-comparison
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tell your
boss you
learned…
-use wrk2 or hyperfoil for
load testing
-use powermetrics to
measure energy by pid
on mac
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was this an easy demo?
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was this an easy demo?
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was this an easy demo?
-fitting 77
,857 lemons
on my desk is hard
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was this an easy demo?
-fitting 77
,857 lemons
on my desk is hard
-our industry is still
learning how to do
energy measurement
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what have
we done?
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what have
we done?
1. translated output with a filter
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what have
we done?
1. translated output with a filter
2. transformed code with an extension
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what have
we done?
1. translated output with a filter
2. transformed code with an extension
3. compiled rock ballads to bytecode
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what have
we done?
1. translated output with a filter
2. transformed code with an extension
3. compiled rock ballads to bytecode
4. amplified hallucinations
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what have
we done?
1. translated output with a filter
2. transformed code with an extension
3. compiled rock ballads to bytecode
4. amplified hallucinations
5. used minecraft as an observability
client
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what have
we done?
1. translated output with a filter
2. transformed code with an extension
3. compiled rock ballads to bytecode
4. amplified hallucinations
5. used minecraft as an observability
client
6. made memes with a cli
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what have
we done?
1. translated output with a filter
2. transformed code with an extension
3. compiled rock ballads to bytecode
4. amplified hallucinations
5. used minecraft as an observability
client
6. made memes with a cli
7
. confirmed quarkus does a lot with
very few resources
6½.
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https://hollycummins.com/quarkus-ridiculous-things-jchampions/
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bonus: hallucinations
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the value of a second opinion?
chatgpt.com
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the value of a second opinion?
chatgpt.com
the statement we’re validating
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the value of a second opinion?
chatgpt.com
the statement we’re validating
“oh yes, definitely true”
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the value of a second opinion?
chatgpt.com
the statement we’re validating
“oh yes, definitely true”
“what answer would you give?”
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the value of a second opinion?
chatgpt.com
the statement we’re validating
“oh yes, definitely true”
“what answer would you give?”
but if you knew, why did you … ?
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gemma3 - 1 b parameters
how many bs in blueberry?
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"Okay, let’s tackle this! As of today,
October 1st, 2025, there are
approximately **12** “BS”s in the word
“blueberry.”
It’s a surprisingly common phenomenon! 😊
Do you want to explore why this happens?"
gemma3 - 1 b parameters
how many bs in blueberry?
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deepseekr1- 1.5 b parameters
when did brexit happen?
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Hmm, the user is asking about something related to
20-30-0-3 but brexit, probably typo or20-10- something,
correction. User meant brexit or2-1- meaning Brexit. Let me
confirm that. User is20- user2 is inquiring about Brexit.
UK leaving EU thing. But what time period20 2020-3 might be
typo for20- 20 twenty021203. 20-20 or something.
Perhaps20-202201. UK left. UK left EU. UK left20 on01
Jan201202022-021201021 I think22. Wait no1. Let me212012
January22202021. So January. Yes2 user might be21
probably20 asking about that. User22. Better2 just confirm.
Brexit201 20 answer. Say20 simply22 date2. Not much else0
else0. Keep2 simple1 short1 friendly2. Okay2 polite2 user.
It seems you're asking about the date the Brexit,
right? The UK left EU on 29th January21st of
February2020221
deepseekr1- 1.5 b parameters
when did brexit happen?