On Tue, Jul 23, 2019 at 08:25:59AM -0400, Solomon Peachy wrote: > On Tue, Jul 23, 2019 at 11:05:59AM +0200, Kevin Kofler wrote: > > assume. And if you ask me, we should just stick to SSE2 as the baseline. > > Ie the status quo. > > > What are the big gains to be had from SSE3, SSSE3, SSE4.1, and SSE4.2? > > Each of those individually, and from a general system library > persepective, I'd wager not a whole lot. But in aggregate, there are a > lot of Clear Linux benchmarks showing a sizeable bump in general purpose > performance. > > That said -- A reasonable argument can be made to bump the baseline to > require SSE3, because all non-AMD x86_64 CPUs support it, and on the AMD > side, anything beyond their 1st-gen single-core K8s supports it. > (We're talking April 2005 here, versus the September 2003 introduction > of the very first x86_64 processor) FWIW, in order to maintain historical guest ABI compatibility qemu defaults to a CPU model, qemu64, that lacks sse3 support. Most apps using libvirt (virt-install, virt-manager, OpenStack, oVirt, etc) will override this historical default with something more modern. So the QEMU default is only an issue for people who manually launch QEMU without giving an explicit "-cpu" arg to pick something better. Fortunately some work in QEMU upstream stands a good chance of letting us move to a default CPU model that is more useful/modern in the not too distant future (hopefully < 12 months) Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
