How to speed up the Rust compiler in July 2026
TL;DR:
TL;DR:
Since December 2025, Rust compiler workloads improved by ~5.6% overall ( ~2.9% excluding rustdoc).
Improvements:
- rustdoc: ~38% mean speedup
- Clippy: 10–30% faster by skipping useless lint calls
- New trait solver benchmark: 27s → under 1s
- Smaller AST nodes and fewer memory copies improved cache use
- Incremental compilation received many smaller optimizations
RipGrep musl binaries occasionally segfault during very-large searches
Article, Comments
https://github.com/dfoxfranke/ripgrep-3494-analysis
Article, Comments
https://github.com/dfoxfranke/ripgrep-3494-analysis
TL;DR: the Linux kernel briefly forgot a memory write. Not really a ripgrep bug, and probably not a musl bug.
During a massive, highly parallel directory search, one thread allocated a page and wrote musl allocator metadata to it. At the same moment another thread was unmapping memory. A Linux 7.0 kernel race between a fresh page fault and the munmap TLB shootdown replaced that page’s backing. Roughly ten CPU instructions later, the first thread reread its own value and got zero instead. Musl correctly noticed impossible/corrupt allocator metadata and crashed. [1]
The investigator reproduced it with about 1.8 million files / 20 GiB, instrumented musl, matched the disappearing write to the core dump, and found it tracks kernel 7.0.12, not the CPU or ripgrep itself. A Linux 7.0 page-table-reclaim change is the prime suspect, though the precise offending commit isn’t proven yet—and the race was reportedly still present in mainline during the analysis. [1]
So, in technical terms: absolutely cursed kernel VM race, exposed by ripgrep doing allocator violence at scale.
Citations
[1] GitHub - dfoxfranke/ripgrep-3494-analysis: Analysis of one crazy segfault in ripgrep · GitHub
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Go 1.27 Interactive Tour
🔸Go 1.27 introduces several new features, including generic methods, improved struct literals, and broader type inference, as well as performance improvements like size-specialized allocation and an experimental SIMD package. Other notable additions include a standard UUID package, a json/v2 package, and various testing and quality-of-life improvements.
02 Aug 2026
💬 comments
🔸Go 1.27 introduces several new features, including generic methods, improved struct literals, and broader type inference, as well as performance improvements like size-specialized allocation and an experimental SIMD package. Other notable additions include a standard UUID package, a json/v2 package, and various testing and quality-of-life improvements.
02 Aug 2026
💬 comments
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Do It by Code
Go 1.27 Interactive Tour 🔸Go 1.27 introduces several new features, including generic methods, improved struct literals, and broader type inference, as well as performance improvements like size-specialized allocation and an experimental SIMD package. Other…
New simd package
Go 1.27 introduces a new experimental simd package that provides portable and vector-size-agnostic SIMD support. It will make use of the hardware instructions if they are available. This package is enabled by setting the environment variable
The
See the proposal issue for more details.
New crypto/mldsa package
The new crypto/mldsa package implements the post-quantum ML-DSA signature scheme specified in FIPS 204.
Go 1.27 introduces a new experimental simd package that provides portable and vector-size-agnostic SIMD support. It will make use of the hardware instructions if they are available. This package is enabled by setting the environment variable
GOEXPERIMENT=simd at build time.The
simd package is available on all architectures, and provides vector types of unspecified size such as Int8s and Float32s. It supports a “scalable” subset of the operations present in the simd/archsimd package that are hardware-supported or easily emulated across architectures and vector widths.See the proposal issue for more details.
New crypto/mldsa package
The new crypto/mldsa package implements the post-quantum ML-DSA signature scheme specified in FIPS 204.
crypto/x509 now supports ML-DSA private keys, public keys, and signatures.crypto/tls now supports ML-DSA signatures in TLS 1.3, with the new MLDSA44, MLDSA65, and MLDSA87 SignatureScheme values.🔥2
According to @glxyresearch, the total losses from the #Coldcard hack may have reached 2,055 $BTC($130M).
More than 7,700 victim addresses have been affected.
More than 7,700 victim addresses have been affected.
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A 3D mesh stores:
- Vertex data: the points making up the mesh
- Index-buffer data: instructions describing which points form each triangle
When a mesh is mirrored using a negative scale, such as
If
Unreal can already render mirrored meshes correctly using "reverse culling"it simply changes which triangle direction counts as the front. Therefore, the second index buffer usually isn’t necessarily required. Unreal’s own HLOD and proxy-mesh generators disable it for this reason.
it exists as a memory-for-performance tradeoff.
So:
means:
“Don’t create the extra reversed copy. Save memory, because Unreal can render negatively scaled/mirrored instances correctly without it.”
This shouldn’t change how the mesh looks; it only avoids unnecessary storage.
- Vertex data: the points making up the mesh
- Index-buffer data: instructions describing which points form each triangle
When a mesh is mirrored using a negative scale, such as
Scale X = -1, its triangles effectively face the opposite direction.If
bBuildReversedIndexBuffer is enabled, Unreal stores a second copy of the triangle instructions in reverse order. This can make mirrored rendering slightly easier, but it roughly doubles the mesh’s index-buffer memory usage.Unreal can already render mirrored meshes correctly using "reverse culling"it simply changes which triangle direction counts as the front. Therefore, the second index buffer usually isn’t necessarily required. Unreal’s own HLOD and proxy-mesh generators disable it for this reason.
it exists as a memory-for-performance tradeoff.
So:
ProxySourceModel.BuildSettings.bBuildReversedIndexBuffer = false;
means:
“Don’t create the extra reversed copy. Save memory, because Unreal can render negatively scaled/mirrored instances correctly without it.”
This shouldn’t change how the mesh looks; it only avoids unnecessary storage.
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Do It by Code
A 3D mesh stores: - Vertex data: the points making up the mesh - Index-buffer data: instructions describing which points form each triangle When a mesh is mirrored using a negative scale, such as Scale X = -1, its triangles effectively face the opposite…
For a negatively scaled mesh, Unreal has two choices:
- Change the GPU’s culling/rasterizer state to treat the reversed winding as front-facing.
- Use a prebuilt reversed index buffer and keep the normal culling state.
The second option can reduce expensive GPU state or pipeline-state changes, especially on older hardware/APIs or when many mirrored meshes are rendered. Historically, that could provide a worthwhile performance improvement.
The downside is memory:
- It roughly doubles index-buffer storage.
- It does not double the entire mesh size; vertex data, materials, textures, and other data are unaffected.
On modern hardware, ordinary reverse culling is generally cheap enough that the extra buffer often provides little or no measurable benefit. That is why proxy/HLOD generation commonly disables it.
So the practical rule is:
- Enable it if you render many negatively scaled, non-Nanite meshes and profiling shows a benefit.
- Disable it otherwise to save cooked asset size and GPU memory.
It is an optimization option, not something required for mirrored meshes to render correctly.
- Change the GPU’s culling/rasterizer state to treat the reversed winding as front-facing.
- Use a prebuilt reversed index buffer and keep the normal culling state.
The second option can reduce expensive GPU state or pipeline-state changes, especially on older hardware/APIs or when many mirrored meshes are rendered. Historically, that could provide a worthwhile performance improvement.
The downside is memory:
- It roughly doubles index-buffer storage.
- It does not double the entire mesh size; vertex data, materials, textures, and other data are unaffected.
On modern hardware, ordinary reverse culling is generally cheap enough that the extra buffer often provides little or no measurable benefit. That is why proxy/HLOD generation commonly disables it.
So the practical rule is:
- Enable it if you render many negatively scaled, non-Nanite meshes and profiling shows a benefit.
- Disable it otherwise to save cooked asset size and GPU memory.
It is an optimization option, not something required for mirrored meshes to render correctly.
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https://www.youtube.com/watch?v=w71JusTenBw
But you can patch your way out of it!
Posted by Brad Spengler, 9 hours ago
But you can patch your way out of it!
Posted by Brad Spengler, 9 hours ago
https://github.com/EpicGames/UnrealEngine/tree/release/Engine/Plugins/Experimental/Animation/AnimGen/Source
AnimGen plugin in UE (experiential) can be used to build and train Machine-Learning-based character animation controllers in the editor and evaluate them at runtime.
example project
AnimGen plugin in UE (experiential) can be used to build and train Machine-Learning-based character animation controllers in the editor and evaluate them at runtime.
example project
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Re: Why does Opus 5 feel worse to work with?
The single biggest annoyance with Opus 5 is that it writes too elliptically.
Sentences that orbit a point, then jump to it like it's a revealed insight.
Unnecessarily abstract phraseology. Constantly using inanimate nouns as the subjects in sentences in order to unlock variety in verb choice, especially when it helps construct a sentence where the real action can 'land' like a surprise at the end.
It is definitely more capable, and yes, I've found it can make unwarranted decisions, but actually I've found Fable worse for that, particularly if it's off in a subagent somewhere out of sight.
And comments are out of control. I have a subsystem in my hobby app that I wrote over a couple of weekends with Opus + Fable. After ~30 or so commits it apparently started instructing subagents to copy the "existing verbose comment style of the codebase" - a verbose style it initiated. A review of the code showed it was approaching 3:1 comments to code ratio. I spent a day's worth of tokens (5x) rephrasing and eliminating comments.
barrkel, 3 hours ago
The single biggest annoyance with Opus 5 is that it writes too elliptically.
Sentences that orbit a point, then jump to it like it's a revealed insight.
Unnecessarily abstract phraseology. Constantly using inanimate nouns as the subjects in sentences in order to unlock variety in verb choice, especially when it helps construct a sentence where the real action can 'land' like a surprise at the end.
It is definitely more capable, and yes, I've found it can make unwarranted decisions, but actually I've found Fable worse for that, particularly if it's off in a subagent somewhere out of sight.
And comments are out of control. I have a subsystem in my hobby app that I wrote over a couple of weekends with Opus + Fable. After ~30 or so commits it apparently started instructing subagents to copy the "existing verbose comment style of the codebase" - a verbose style it initiated. A review of the code showed it was approaching 3:1 comments to code ratio. I spent a day's worth of tokens (5x) rephrasing and eliminating comments.
barrkel, 3 hours ago
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https://ai.google.dev/responsible/docs/safeguards/synthid
https://deepmind.google/models/synthid/
https://www.anthropic.com/news/claude-text-watermark
https://deepmind.google/models/synthid/
https://www.anthropic.com/news/claude-text-watermark
Practically speaking, SynthID Text is a logits processor, applied to your model's generation pipeline after Top-K and Top-P, that augments the model's logits using a pseudorandom g-function to encode watermarking information in a way that helps you determine if the text was generated by your model, without significantly affecting text quality. See the paper for a complete technical description of the algorithm and analyses of how different configuration values affect performance.
Watermarks are configured to parameterize the g-function and how it is applied during generation. Each watermarking configuration you use should be stored securely and privately, otherwise your watermark may be trivially replicable by others.
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Gemini 3.7 Flash wins an AoE II skirmish on Moderate difficulty (first time for any model).
Averaged 11.9 tool calls per tick, 4.4 ticks/min, almost 50 actions per minute
Seems like it is managing tools and following instruction better than 3.6.
Posted by Wyatt Walls, 2 days ago
Averaged 11.9 tool calls per tick, 4.4 ticks/min, almost 50 actions per minute
Seems like it is managing tools and following instruction better than 3.6.
Posted by Wyatt Walls, 2 days ago
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Do It by Code
go 1.27's method generics https://go.dev/doc/go1.27#language https://github.com/golang/go/issues/77273
Go 1.27 is released
go.dev
Go 1.27 is released - The Go Programming Language
Go 1.27 adds generic methods, encoding/json/v2 package, uuid package, faster memory allocation, goroutine leak profiles, and more.
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‼️Two popular Rust crates, arrayref and append-only-vec, were compromised in a supply chain attack. arrayref alone has 244M downloads. The malware ran at build time, which means anyone who compiled a project that pulled one in was hit, without ever calling the crate.
Here's the breakdown 🧵
Posted by Aikido, 40 minutes ago
Here's the breakdown 🧵
Posted by Aikido, 40 minutes ago
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CVE-2026-33824: Windows Internet Key Exchange (IKE) Service Extensions Remote Code Execution Vulnerability (critical; score: 9.8/10)
- Microsoft Update Guide
- CISA
Affected versions: nearly all supported versions of windows.
actively exploited, needs no auth or user interaction. The only requirement is for the service to be reachable over the network.
Double free in Windows IKE Extension allows an unauthorized attacker to execute code over a network.
The bug lies in how Windows handles IKEv2 fragmented network packets. Attackers can target any exposed machine by sending malicious traffic over UDP ports 500 or 4500.
- Microsoft Update Guide
- CISA
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Do It by Code pinned «CVE-2026-33824: Windows Internet Key Exchange (IKE) Service Extensions Remote Code Execution Vulnerability (critical; score: 9.8/10) Affected versions: nearly all supported versions of windows. actively exploited, needs no auth or user interaction. The only…»