gentoo
Folly
gentoo | Folly | |
---|---|---|
51 | 90 | |
1,992 | 27,118 | |
0.8% | 0.5% | |
10.0 | 9.8 | |
5 days ago | about 15 hours ago | |
Shell | C++ | |
- | Apache License 2.0 |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
gentoo
- Backdoor in upstream xz/liblzma leading to SSH server compromise
-
Vulkan Video Extensions for Accelerated H.264 and H.265 Encode
Whilst Firefox may support hardware video decoding, Mesa since March 2022 disables patent encumbered codecs by default[1], and distributions such as Fedora and OpenSuse do not explicitly enable these patent encumbered codecs to avoid possible legal problems. Even Gentoo (built from source code by the user) requires the user to explicitly enable a USE flag (proprietary-codes) to use patent encumbered codecs.[2]
The thought process is that AMD, NVIDIA, Intel and the likes are not providing a patent license with their hardware.[3] They are instead just supplying part of an overall system that together with operating system kernel, display manager software, video player software, etc allows the decoding and encoding of patent encumbered video files. Open source software projects and distributions are concerned they'd be found to be infringing patents by enabling a complete solution out-of-the-box. Hence they put some hurdles in place so that a user has to go out of their way to separately piece together the various parts to form a complete system capable of encoding and decoding patent encumbered codecs.
[1] https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15...
[2] https://github.com/gentoo/gentoo/commit/1265a159743d7f07185a...
[3] https://lists.fedoraproject.org/archives/list/[email protected]...
-
I like gentoo's package deprecation process
Thank you! I don't live in git and this helps! Normally under gentoo I shouldn't have to. This actual git https://github.com/gentoo/gentoo (as opposed to the gentoo browser view) plus this "checkout the commit" should get me much further. ... And probably deserve some space in the gentoo docs.
- Great news java people: Gradle eclass is in the works!
- LLVM stages
-
Is gentoo difficult to maintain as a daily driver?
You choose - here's a list
- Error 2124 when trying to interact with super-block (show-super, set-option)
- HTTP-Tiny: verify_SSL (Draft PR)
-
My CNCF LFX Mentorship Spring 2023 Project at Kubescape
(pending) gentoo/gentoo #30595 sys-cluster/kubescape: new package, add 2.2.6
-
Why do the desktop profiles add so many USE flags?
profiles/targets/desktop/make.defaults:
Folly
-
Ask HN: How bad is the xz hack?
https://github.com/facebook/folly/commit/b1391e1c57be71c1e2a...
-
Backdoor in upstream xz/liblzma leading to SSH server compromise
https://github.com/facebook/folly/pull/2153
-
A lock-free ring-buffer with contiguous reservations (2019)
To set a HP on Linux, Folly just does a relaxed load of the src pointer, release store of the HP, compiler-only barrier, and acquire load. (This prevents the compiler from reordering the 2nd load before the store, right? But to my understanding does not prevent a hypothetical CPU reordering of the 2nd load before the store, which seems potentially problematic!)
Then on the GC/reclaim side of things, after protected object pointers are stored, it does a more expensive barrier[0] before acquire-loading the HPs.
I'll admit, I am not confident I understand why this works. I mean, even on x86, loads can be reordered before earlier program-order stores. So it seems like the 2nd check on the protection side could be ineffective. (The non-Linux portable version just uses an atomic_thread_fence SeqCst on both sides, which seems more obviously correct.) And if they don't need the 2nd load on Linux, I'm unclear on why they do it.
[0]: https://github.com/facebook/folly/blob/main/folly/synchroniz...
(This uses either mprotect to force a TLB flush in process-relevant CPUs, or the newer Linux membarrier syscall if available.)
-
Appending to an std:string character-by-character: how does the capacity grow?
folly provides functions to resize std::string & std::vector without initialization [0].
[0] https://github.com/facebook/folly/blob/3c8829785e3ce86cb821c...
-
Can anyone explain feedback of a HFT firm regarding implementation of SPSC lock-free ring-buffer queue?
My implementation was quite similar to Boost's spsc_queue and Facebook's folly/ProducerConsumerQueue.h.
-
A Compressed Indexable Bitset
> How is that relevant?
Roaring bitmaps and similar data structures get their speed from decoding together consecutive groups of elements, so if you do sequential decoding or decode a large fraction of the list you get excellent performance.
EF instead excels at random skipping, so if you visit a small fraction of the list you generally get better performance. This is why it works so well for inverted indexes, as generally the queries are very selective (otherwise why do you need an index?) and if you have good intersection algorithms you can skip a large fraction of documents.
I didn't follow the rest of your comment, select is what EF is good at, every other data structure needs a lot more scanning once you land on the right chunk. With BMI2 you can also use the PDEP instruction to accelerate the final select on a 64-bit block: https://github.com/facebook/folly/blob/main/folly/experiment...
-
Defer for Shell
C++ with folly's SCOPE_EXIT {} construct:
https://github.com/facebook/folly/blob/main/folly/ScopeGuard...
-
Is there any facebook/folly community for discussion and Q&A?
Seems like github issues taking a long time to get any response: https://github.com/facebook/folly
-
How a Single Line of Code Made a 24-Core Server Slower Than a Laptop
Can't speak for abseil and tbb, but in folly there are a few solutions for the common problem of sharing state between a writer that updates it very infrequently and concurrent readers that read it very frequently (typical use case is configs).
The most performant solutions are RCU (https://github.com/facebook/folly/blob/main/folly/synchroniz...) and hazard pointers (https://github.com/facebook/folly/blob/main/folly/synchroniz...), but they're not quite as easy to use as a shared_ptr [1].
Then there is simil-shared_ptr implemented with thread-local counters (https://github.com/facebook/folly/blob/main/folly/experiment...).
If you absolutely need a std::shared_ptr (which can be the case if you're working with pre-existing interfaces) there is CoreCachedSharedPtr (https://github.com/facebook/folly/blob/main/folly/concurrenc...), which uses an aliasing trick to transparently maintain per-core reference counts, and scales linearly, but it works only when acquiring the shared_ptr, any subsequent copies of that would still cause contention if passed around in threads.
[1] Google has a proposal to make a smart pointer based on RCU/hazptr, but I'm not a fan of it because generally RCU/hazptr guards need to be released in the same thread that acquired them, and hiding them in a freely movable object looks like a recipe for disaster to me, especially if paired with coroutines https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p05...
-
Ask HN: What are some of the most elegant codebases in your favorite language?
Not sure if it's still the case but about 6 years ago Facebook's folly C++ library was something I'd point to for my junior engineers to get a sense of "good" C++ https://github.com/facebook/folly
What are some alternatives?
gentooLTO - A Gentoo Portage configuration for building with -O3, Graphite, and LTO optimizations
abseil-cpp - Abseil Common Libraries (C++)
torbrowser-overlay - Gentoo overlay for Tor Browser related ebuilds
Boost - Super-project for modularized Boost
cmake-init-conan-example - cmake-init generated executable project with Conan integration
Seastar - High performance server-side application framework
cmake-init-vcpkg-example - cmake-init generated executable project with vcpkg integration
parallel-hashmap - A family of header-only, very fast and memory-friendly hashmap and btree containers.
llvm-overlay - Unofficial experimental gentoo overlay for compiling llvm with additional components
EASTL - Obsolete repo, please go to: https://github.com/electronicarts/EASTL
cmake-init - The missing CMake project initializer
OpenFrameworks - openFrameworks is a community-developed cross platform toolkit for creative coding in C++.