Join us for the HPSF Community Summit 2026 in Braunschweig, Germany, February 25-27! 💚
Learn what’s new with HPSF projects, give us feedback on your use of HPSF software, meet with project communities, and tell us how to grow and improve them.
Details: hpsf.io/event/hpsf-c...
28.01.2026 15:45
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Intro to the GitButler CLI
YouTube video by GitButler
Love the GitButler GUI but miss your CLI? Have we got the solution for you!
youtu.be/Jg8L3SbgZ3o?...
11.02.2026 08:05
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Please note: Any claims of AI Exascale, AI Zettascale or beyond computing power are just baloney. Real computing power is measured in FP64. Period.
AMD embraced utter stupidity by adopting this terminology by the leather jacket man.
It's a really shame!
#CES2026 #AMD
06.01.2026 03:08
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![title slide of talk being given at Rust Nation UK:
[Title] Rust for Foundational SW or: Safety-Critical Software in Rust](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:nzjdb45ypvwdnixflhodgn4z/bafkreihmuu63icftjaynofj2eirc4r3dxphvw7ayhkcdmlvlfjstcaxbau)
title slide of talk being given at Rust Nation UK:
[Title] Rust for Foundational SW or: Safety-Critical Software in Rust
ever curious why people that work in safety-critical systems want to use Rust?
here's the title slide for the talk i'll give at @rustnationuk.bsky.social about this
28.12.2025 23:37
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When compilers surprise you — Matt Godbolt’s blog
Sometimes compilers can surprise and delight even a jaded old engineer like me
Day 24 of #AoCO2025! A loop summing 0+1+2+...+n. GCC unrolls it. Clang does something jaw-dropping: the loop vanishes entirely, replaced by a direct calculation. How?!
xania.org/202512/24-cu...
youtu.be/V9dy34slaxA
24.12.2025 13:21
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Day 23 of #AoCO2025! Switch → jump table? Sometimes. Other times: arithmetic, bitmasks, or something cleverer. Compilers have more tricks than you think.
xania.org/202512/23-sw...
youtu.be/aSljdPafBAw
23.12.2025 12:35
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Clever memory tricks — Matt Godbolt’s blog
We learn that compilers have tricks to access memory efficiently
Day 22: String comparison against "ABCDEFG" should call memcmp, but Clang inlines it with some clever memory tricks. How does it compare 7 bytes so efficiently? xania.org/202512/22-me... youtu.be/kXmqwJoaapg #AoCO2025
22.12.2025 12:57
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When SIMD Fails: Floating Point Associativity — Matt Godbolt’s blog
Why floating point maths doesn't vectorise like integers, and what to do about it
Day 21: Summing integers? Compiler vectorises beautifully—8 at a time! Switch to floats? It refuses, doing each add individually. Same code, totally different output. Why? 🤔
xania.org/202512/21-ve...
youtu.be/lUTvi_96-D8
#AoCO2025
21.12.2025 13:34
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Day 20: Process 65,536 integers one at a time? Nah. The compiler vectorises it to handle 8 at once — same code, 8× faster! SIMD auto-vectorisation is compiler magic 🚀
xania.org/202512/20-si...
youtu.be/d68x8TF7XJs #AoCO2025
20.12.2025 12:58
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Chasing your tail — Matt Godbolt’s blog
The art of not (directly) coming back: tail call optimisation
Day 19: Recursive functions calling themselves endlessly — stack growth? Nope! The compiler turns recursion into loops. Tail call optimisation is magic ✨
xania.org/202512/19-ta...
youtu.be/J1vtP0QDLLU #AoCO2025
19.12.2025 13:01
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Partial inlining — Matt Godbolt’s blog
Inlining doesn't have to be all-or-nothing
Day 18: Function with fast & slow paths. Inline = code bloat. Don't inline = slow fast path. Can't have both—or can you? The compiler finds a surprising way out of this dilemma.
xania.org/202512/18-pa...
youtu.be/STZb5K5sPDs
#AoCO2025
18.12.2025 13:05
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Actually, this die configuration is not new information, it was already mentioned on this removed slide:
(Although the CPU die's CBB name is seems still new.)
18.12.2025 10:47
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It’s safe to assume that the HPC scheduling space is going to be in a state of Flux for quite some time to come…
(I see what I did there. With consummate apologies to @vsoch.bsky.social and @tgamblin.bsky.social in advance 🤣)
17.12.2025 17:56
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How have servers and the cloud evolved in the last 30 years, and what might be next? @bcantrill.bsky.social has been at the thick of the industry since the Dotcom Boom, and shares fascinating stories.
Bryan is one of my all-time favorite people to talk with - don't miss this one.
(cont'd)
17.12.2025 21:02
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Inlining - the ultimate optimisation — Matt Godbolt’s blog
Copy paste can sometimes be a good thing, at least if the compiler does it for you
Day 17: Inlining — the ultimate optimisation ✨
A function gets inlined, half vanishes. The assembly is cleaner than hand-written. How does copy-paste make code disappear?
xania.org/202512/17-in...
youtu.be/JFHfFTvMPp0
#AoCO2025
17.12.2025 12:27
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Calling all arguments — Matt Godbolt’s blog
Knowing how compilers call functions can help with design - and optimisation
Day 16: Calling conventions matter! Pass 8 chars as separate args: stack spillage. Pack them in a struct: single register. Sometimes structs are MORE efficient than separate parameters!
xania.org/202512/16-ca...
youtu.be/Yaw8AMoP4sI
#AoCO2025
16.12.2025 12:59
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Aliasing — Matt Godbolt’s blog
Knowing when the compiler can't optimise is important too
Day 15: Two nearly identical loops—one writes to memory every iteration, the other stays in registers. Same code, wildly different performance. The culprit? Aliasing!
xania.org/202512/15-al...
youtu.be/PPJtJzT2U04
#AoCO2025
15.12.2025 13:20
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Does this mean no more dirt-cheap NRE from Slurm? Or will Slurm development no longer be coin-operated? Would love to see serious engineering effort go into modernizing Slurm, but this could go in many directions.
15.12.2025 17:40
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When LICM fails us — Matt Godbolt’s blog
When aliasing can prevent loop-invariant code motion
Day 14: Add ONE global counter to your loop and watch LICM vanish—strlen called every iteration! Why would incrementing an unrelated variable break the optimisation? 🤔
xania.org/202512/14-li...
youtu.be/OwFNblEEAXo
#AoCO2025
14.12.2025 13:10
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Loop-Invariant Code Motion — Matt Godbolt’s blog
The compiler can move code outside of loops to speed things up
Day 13 of Advent of Compiler Optimisations! 🔄
Loop calling a function whose result never changes? One compiler hoists it out automatically. The other… doesn't. Even with hints!
xania.org/202512/13-li...
youtu.be/dIwaqJG0WDo
#AoCO2025
13.12.2025 13:08
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Pointer Arith (Using the GNU Compiler Collection (GCC))
Pointer Arith (Using the GNU Compiler Collection (GCC))
Cursed code:
void* f(void *p) {
return p + 1;
}
Both gcc and clang support void* arithmetic as an extension in C:
gcc.gnu.org/onlinedocs/g...
-pedantic FTW!
Godbolt: godbolt.org/z/rcrqWvMGW
#Programming
12.12.2025 17:57
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Unswitching loops for fun and profit — Matt Godbolt’s blog
Duplicating loops around can yield some decent optimisations
Day 12 of Advent of Compiler Optimisations! A loop that checks the same thing every time. The compiler's solution? Make the code bigger to make it faster. Wait, what? xania.org/202512/12-lo... youtu.be/-VCrYshE7iQ #AoCO2025
12.12.2025 12:46
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Day 11: A clever bit-counting loop using the "clear bottom bit" trick. Change one compiler flag and... wait, what just happened to my loop?! Pattern recognition at its finest.
xania.org/202512/11-po...
youtu.be/Hu0vu1tpZnc
#AoCO2025
11.12.2025 13:11
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Kokkos 5.0 is officially out. ✨
Details:
- Moves the project to C++20
- Retires older interfaces, reducing complexity for future work
- Ideal time for teams to review workflows
Read the full update here: hpsf.io/blog/2025/ko...
11.12.2025 17:39
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Where did you guys get the info for the facility power draw and cooling limits? 👀 Was it publicly announced somewhere?
10.12.2025 22:44
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