We discussed this at the CentOS Board meeting last week and generally agreed with the overall idea of the SIG. There were two main questions that came up: 1) What is the contribution model the SIG is envisioning? How will people be able to participate in the SIG? Could you add this to the proposal? 2) There are existing Intel people working in the Hyperscaler SIG on some optimized libraries. How would the Hyperscaler SIG coordinate with the X86 SIG in this regard? There is a desire to share work and not duplicate effort. This seems like something we can work out once the SIG is approved. I am happy to act as the Board sponsor for this SIG and I believe we should work through any missing pieces or logistics before next month's Board meeting. josh On Mon, Feb 27, 2023 at 12:23 PM Florian Weimer <fweimer at redhat.com> wrote: > > # Goals > > The purpose of this SIG is to quantify the potential benefits of > applying existing compiler technology to distribution packages, > targeting more recent CPUs, and evaluating different options for how > these optimizations can be maintained in a scalable way, and delivered > to end users. > > Today, there is a significant delay between the release of new x86-64 > ISAs and the adoption across the entire CentOS distribution. For > example, CentOS 9 Stream released with the x86-64-v2 ISA baseline, nine > to thirteen years after such CPUs became commercially available. The > concern is that this discrepancy leaves more recent CPU features unused, > and end users do not see the best possible performance for the CPUs they > use. > > Parts of the distribution are built with run-time selected > optimizations, but this only applies to specialized functional areas, > such as string manipulation, certain mathematical operations, and > cryptography, but not (for example) to language interpreters that are > part of CentOS. > > # Status > > Proposed: RFC and looking for a sponsoring Governing Board member > > # What’s in scope > > * Explore the immediate runtime performance impact of package-specific > ISA-related work on key workloads e.g. language interpreters. > > * Evaluate the performance benefit at run-time of building CentOS with > auto-vectorization and the very-cheap cost model and different x86-64 > micro-architecture levels. > > * Explore ways how these performance-enhancing builds can be maintained > at the distribution level and made available to end users for > installation. > > * Assess the image/container size impact of those additional optimized > builds (this may not be applicable to some delivery mechanisms). > > * Explore ways to alert users that they do not get optimal performance > because of misconfigured hypervisors. > > * It is possible, but not likely, that work across the entire > distribution may be needed to enable shadow stacks. (Userspace > enablement happened as part of CentOS 8, but the kernel parts are not > upstream and have changed significantly, so there is some > uncertainty.) If large-scale work affecting many packages is needed, > the SIG would be a natural place to prototype changes before > integration into the distribution. > > # What's not in scope > > * Enablement for future x86 CPUs and chipsets, assemblers, linkers, and > compiler support for new ISAs including regular performance work on > individual packages (e.g., identified upstream backports). Hardware > enablement must follow existing processes. > > * Any 32-bit work (such as 64-bit time_t, or a 32-bit kernel) is > explicitly excluded. > > * The focus will be on userspace changes. > > * Rebuilds for potential observability improvements are out of scope > (although shadow stacks are expected to help in this a > > * Adding additional hosts to the CentOS infrastructure in support of > this SIG needs to be negotiated with the CentOS infrastructure > team. The CPU microarchitecture level of the existing infrastructure > is already sufficient. > > # Roadmap > > March 2023: Start the SIG and coordinate with partners > April 2023: Adopt existing CentOS builder resources to deliver the > required builds. > May 2023: Initial performance analysis results. > > Rest TBD based on results of exploration. > > Resources > > They SIG could benefit from spare x86-64 Koji builder capacity. > > _______________________________________________ > CentOS-devel mailing list > CentOS-devel at centos.org > https://lists.centos.org/mailman/listinfo/centos-devel