On 18/09/2023 17:46, Stefan Hanreich wrote: > One of our users ran into issues with running Ceph on older CPU > architectures [1]. This is apparently due to a bug in gcc-12 that > leads to SSE 4.1 instructions always being executed rather than > dynamically dispatching functions using those instructions. Those > binaries then break on older CPUs that do not support this instruction > set. > > I've ran some benchmarks with `rados bench` against our last release > (18.2.0-pve2) and this new version. The commands were taken from our > latest Ceph benchmarking paper [2]. The results showed that this patch > does not lead to performance regressions on newer hardware. > > 18.2.0-pve2 this patch > Read EC 4574.28 4651.95 > Write EC 3739.59 3773.87 > Read Replicated 5345.34 5568.41 > Write Replicated 4123.28 4066.19 > (numbers correspond to bandwidth in MB/s) > > [1] > https://forum.proxmox.com/threads/proxmox-8-ceph-quincy-monitor-no-longer-working-on-amd-opteron-2427.129613 > [2] > https://www.proxmox.com/en/downloads/proxmox-virtual-environment/documentation/proxmox-ve-ceph-benchmark-2020-09 > > Signed-off-by: Stefan Hanreich <s.hanre...@proxmox.com> > --- > ...y-with-CPUs-not-supporting-SSE-4.1-i.patch | 32 +++++++++++++++++++ > patches/series | 1 + > 2 files changed, 33 insertions(+) > create mode 100644 > patches/0015-fix-compatibility-with-CPUs-not-supporting-SSE-4.1-i.patch > >
applied, with a reworded commit message, shifting the blame to the combination of gf-complete and gcc-12, as the former does some rather funky stuff too, thanks! Having this reported to the GCC and/or gf-complete people, ideally with a reduced example (compiling ceph is a bit overkill ;-) Using elfx86exts [0] as mentioned in the debian bug [1] should be enough to ensure your reduced example is still affected and contains SSE 4.1 instructions. [0]: https://github.com/pkgw/elfx86exts [1]: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1012935#10 _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel