
@RedHat Engineer in @OpenJDK + @GraalVM team. @JBoss and @Infinispan Alumni. FP enthusiast. Talo iberiko bilbotarra. Long suffering wife. 🐶 🏂 🎾 ⚽️ 🤓
Basel, Switzerland
Joined November 2008
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Galder Zamarreño retweeted
Hyperthreading is Dead.
Major CPU manufacturers (including Intel) are getting ready to abandon SMT hyperthreading completely.
It's not as crazy as you think. In fact, Apple, Qualcomm, and Samsung have *never* used Hyperthreading.
But why?
🧵
Galder Zamarreño retweeted
Java 23 is out, but no one’s talking about the real MVPs! Thanks to @forked_franz for digging up the secondary cache bug that caused scalability issues for so many apps. Then @AndrewHaley13 made github.com/openjdk/jdk/pull/… - Huge improvement for Java devs! #Java23 #OpenJDK
Galder Zamarreño retweeted
Replying to @QuarkusIO
@QuarkusIO achieved an amazing milestone today, as the core repo reached 1000 contributors 🥳!
I'd like to thank all contributors for all the hard work as the project would not be as successful as it is without their fantastic help 💕!
Galder Zamarreño retweeted
The new processors that AMD is producing (AMD Zen 5) will have 4 full width (512 bits) execution units for AVX-512. This will make AVX-512 instructions especially powerful.
The complicated history behind AVX-512 makes the issue murkier. In some circles, AVX-512 got a bad reputation, and for good reason. But this bad reputation is no longer warranted.
Let me explain.
Early Intel implementations of AVX-512 in processors such as Skylake would drastically reduce the processor's frequency. This made the engineering difficult.
It is important to stress than in recent AVX-512 processors (AMD Zen 4, Intel Ice Lake...), it is no longer the case. You should expect that the frequency might be slightly lower when making use of AVX-512, but it is no longer something you need to worry about. (Processors adjust their frequency all the time.)
Here are numbers I just got on a simdutf transcoding benchmark on an Ice Lake processsor...
SSSE3 : 3.2 GHz
AVX2 : 3.2 GHz
AVX-512 : 3.1 GHz
At a glance, that's a negative for the AVX-512 routine. But nobody cares about the frequency, we care about the speed... let us look at the transcoding speed...
SSSE3 : 2.5 GB/s
AVX2 : 3.0 GB/s
AVX-512 : 5.3 GHz
So the AVX-512 routine is clearly faster.
The same will hold for AMD Zen 4 and, very likely, for AMD Zen 5.
Galder Zamarreño retweeted
Leyden is going to be a breakthrough technology for startup and time-to-performance improvements. There are many other things that could be improved, squeezing even more perf. Just a taste:
Galder Zamarreño retweeted
The reality is KDB barely touched the ball centrally. His heatmap shows he was operating almost exclusively in wide spaces to facilitate City’s attacks. Reflective of the change we’ve seen from City so far, with more focus on attacking from wide areas xitter.cf/city_tactics/status/18…
Galder Zamarreño retweeted
EPFL PhD student Stella Laperrousaz’s crowd-pleasing comparison of her research on electronic fibers to one of Switzerland’s most famous exports won her the audience prize at the My Thesis in 180 Seconds Competition Switzerland 2024.
go.epfl.ch/09c312
Galder Zamarreño retweeted
Spain’s wingers have taken much of the credit for their newfound directness. But what about the midfielders? Olmo, Ruiz and Merino’s constant running into the box was crucial yesterday. ⬇️
nytimes.com/athletic/5619753…
Galder Zamarreño retweeted
There have been many words written about Horizon, but few about *what was actually wrong with it*. Those of us who try to write reliable software might find these interesting.
judiciary.uk/wp-content/uplo…... benthamsgaze.org/2021/07/15/…
Galder Zamarreño retweeted
POV: You’re flying through #ArtBasel’s most spectacular sector ✈️
Our drone glides through Unlimited, our sector dedicated to artworks challenging the limitations of a traditional art fair booth.
Time to take off: bit.ly/3z9Ojko
Galder Zamarreño retweeted
Hey @easyJet why do you need full calendar access on iOS?
Granted you the ability to add, but that’s.
Why isn’t this enough?
Don’t see why you need to see my full calendar to add an event in my diary.
Galder Zamarreño retweeted
Mechanical engineering student Jade Gibouin is this year’s CEO of the EPFL Racing Team, which will unveil its new electric racing car tonight. She devotes all spare time to this project – and she’s proud that women now make up one-quarter of the team.
go.epfl.ch/778f8d
Galder Zamarreño retweeted
java launcher accepts multiple JVMs. It dawned on me last night: you can frankenstein a JDK build that includes additional *debug* JVMs! Then, when a customer experiences a VM bug, you just ask for an additional JVM flag. (CDS complains a bit about modules version, expectedly.)
Galder Zamarreño retweeted
🎉🥳 Lilliput 4-Byte headers - IT’S ALIVE!! 🥳🎉
I can now allocate objects with a bunch of fields (e.g. 4 bytes or 1 int or 1 reference) into a single 64-bit word 😁
Galder Zamarreño retweeted
And that is exactly what we've done across LTSs in @QuarkusIO for HTTP 2 (and not only), but spanning across 3 different projects (quarkus, @vertx_project and @netty_project), see github.com/quarkusio/quarkus…
Sunday rant.
For software engineering, my sense is that the phrase “premature optimization is the root of all evil” has massively backfired. Its from a book on data structures and mainly tried to dissuade people from prematurely write things in assembler. But the point was to free you up to think harder about the data structures to use, not leave things comically inefficient. This context is always skipped when it’s uttered.
Not all fast software is world-class, but all world-class software is fast. Performance is _the_ killer feature.
If you are in engineering, here is a fantastic anecdote. I refer to this account often. It’s a bit subtile, but the implications are massive-
It’s an account of how SQLite became 50% faster, not by doing one specific thing but hundreds of small ones.
SQLite is everywhere today because of this work.
sqlite-users.sqlite.narkive.…
We need the engineers in all companies fight for this more. Product leads are not the right owners of the end performance of the software. This needs to be encoded in the professional pride of the software engineering discipline. Leaders in companies need to encourage it and hold engineering accountable. It’s simply not ok to fritter away the performance of the products for random reasons.
Every user of your products cares exactly as much about latency as engineers do when typing in their terminal. They just don’t have the words to describe what they don’t like about the experience and neither should they.
Galder Zamarreño retweeted
A new EPFL study has demonstrated the persuasive power of Large Language Models, finding that participants debating GPT-4 with access to their personal information were far more likely to change their opinion compared to those who debated humans.
actu.epfl.ch/news/ai-s-new-p…
Galder Zamarreño retweeted
El Athletic Club y su filosofía, tan lejos de los Rubiales y de los negocios oscuros y tan cerca de lo que es la esencia del fútbol.
🎙️ La firma de Àngels Barceló.
cadenaser.com/nacional/2024/…
Galder Zamarreño retweeted
"Never forget that one of the principles of @AthleticClub is the Basque language. You don't know how beautiful it is to hear you speak Basque at the San Mames stadium, in Bilbao, on the street, everywhere. To young people: keep using Basque. To adults: keep teaching it!" – at Washington, DC


























