https://bugzilla.suse.com/show_bug.cgi?id=1227345 Bug ID: 1227345 Summary: Kernel 6.9 (MicroOS): a single cpu core is available. Classification: openSUSE Product: openSUSE Tumbleweed Version: Current Hardware: x86-64 OS: Other Status: NEW Severity: Normal Priority: P5 - None Component: Kernel Assignee: kernel-bugs@opensuse.org Reporter: maxime.thirion@r-virtuel.net QA Contact: qa-bugs@suse.de Target Milestone: --- Found By: --- Blocker: --- Created attachment 875851 --> https://bugzilla.suse.com/attachment.cgi?id=875851&action=edit htop showing only one core Hello everyone ! Overview: I'm experiencing a really strange problem on two servers, in production, hosted by the Hetzner company. Since upgrading to kernel 6.9, only one cpu core is available, giving catastrophic performance. The strange thing is that the two machines are not identical: The first server has an Intel(R) Xeon(R) CPU E3-1275 v5 with 2x 512Gb NVME SSD and 64Gb ram. The second server has an Intel(R) Core(TM) i7-3770 CPU with 4x 6TB HDD and 32Gb ram. I contacted the hosting company first, who told me they didn't know about the problem. With their suggestion, I restarted one of the machines on their rescue system, which has a 6.9.7 kernel, so it's also very recent, and the problem doesn't exist: all the cpu cores are activated. Steps to Reproduce : Update to kernel 6.9 Actual Results: Only one CPU core is available, and performance is very poor. lscpu gives only one core per socket and only one tread per core. kutta:~ # lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Address sizes: 39 bits physical, 48 bits virtual Byte Order: Little Endian CPU(s): 1 On-line CPU(s) list: 0 Vendor ID: GenuineIntel BIOS Vendor ID: Intel(R) Corporation Model name: Intel(R) Xeon(R) CPU E3-1275 v5 @ 3.60GHz BIOS Model name: Intel(R) Xeon(R) CPU E3-1275 v5 @ 3.60GHz To Be Filled By O.E.M. CPU @ 3.6GHz BIOS CPU family: 179 CPU family: 6 Model: 94 Thread(s) per core: 1 Core(s) per socket: 1 Socket(s): 1 Stepping: 3 CPU(s) scaling MHz: 36% CPU max MHz: 4000.0000 CPU min MHz: 800.0000 BogoMIPS: 7202.00 Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology n onstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowpr efetch cpuid_fault epb pti ssbd ibrs ibpb stibp tpr_shadow flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid mpx rdseed adx smap clflushopt intel_pt xsaveopt xsavec xgetbv1 xsaves d therm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp vnmi md_clear flush_l1d arch_capabilities Virtualization features: Virtualization: VT-x Caches (sum of all): L1d: 32 KiB (1 instance) L1i: 32 KiB (1 instance) L2: 256 KiB (1 instance) L3: 8 MiB (1 instance) NUMA: NUMA node(s): 1 NUMA node0 CPU(s): 0 Vulnerabilities: Gather data sampling: Vulnerable: No microcode Itlb multihit: KVM: Mitigation: VMX disabled L1tf: Mitigation; PTE Inversion; VMX conditional cache flushes, SMT disabled Mds: Mitigation; Clear CPU buffers; SMT disabled Meltdown: Mitigation; PTI Mmio stale data: Mitigation; Clear CPU buffers; SMT disabled Reg file data sampling: Not affected Retbleed: Mitigation; IBRS Spec rstack overflow: Not affected Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization Spectre v2: Mitigation; IBRS; IBPB conditional; STIBP disabled; RSB filling; PBRSB-eIBRS Not affected; BHI Not affected Srbds: Mitigation; Microcode Tsx async abort: Mitigation; TSX disable Expected Results: Correct and optimal operation of the cpu, with all cores activated, as with kernels 6.8 and earlier or with 6.9 supplied by the provider's rescue system. Additional Information: Any other useful information. I couldn't find the system in the list but it's OpenSUSE MicroOS, so the servers have a read-only file system and they're in production (which limits my testing and reinstallation possibilities). I did a rollback on the server with the Xeon that was still in 6.4 and the problem no longer appears. I no longer have a snapshop with an old kernel on the i7, as I didn't see the problem immediately. I can do some "tests" on this server if necessary. The servers were up to date (before the Xeon rollback). -- You are receiving this mail because: You are on the CC list for the bug.