I recently noticed a pretty bad regression in performance in tokio (the most popular async runtime for Rust), and reported it with tokio: https://github.com/tokio-rs/tokio/issues/5955 The profiling results / flamegraphs I posted on the issue show a pretty bleak picture. Doing some digging with help from tokio developers, it appears that the standard mechanism by which Rust code can request memory alignment (annotating structs with "#[repr(align(N))]" where N is a power of 2) relies on posix_memalign, which started being *much much slower* with glibc 2.38: https://doc.rust-lang.org/reference/type-layout.html#the-alignment-modifiers https://sourceware.org/pipermail/libc-alpha/2023-August/150653.html This is pretty bad for a performance sensitive component like an async runtime. Reproducible: Always
FEDORA-2023-a650119fa5 has been submitted as an update to Fedora 39. https://bodhi.fedoraproject.org/updates/FEDORA-2023-a650119fa5
This was already fixed in dist-git, but we forgot to submit the Bodhi update.
Looks like I ran my tests only a few hours before rawhide got glibc-2.38.9000-5.fc40, which also has these changes ... I'll re-run the tests with the new versions, thanks!
FEDORA-2023-a650119fa5 has been pushed to the Fedora 39 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2023-a650119fa5` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2023-a650119fa5 See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.
FEDORA-2023-24a71a63ed has been pushed to the Fedora 39 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2023-24a71a63ed` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2023-24a71a63ed See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.
FEDORA-2023-24a71a63ed has been pushed to the Fedora 39 stable repository. If problem still persists, please make note of it in this bug report.