On Tue, 1 Dec 2020 07:35:37 +0100 Zdenek Kaspar <zkaspar82@xxxxxxxxx> wrote: > On Thu, 19 Nov 2020 04:05:26 +0100 > Zdenek Kaspar <zkaspar82@xxxxxxxxx> wrote: > > > Hi, > > > > in my initial report > > (https://marc.info/?l=kvm&m=160502183220080&w=2 - now fixed by > > c887c9b9ca62c051d339b1c7b796edf2724029ed) I saw degraded > > performance going back somewhere between v5.8 - v5.9-rc1. > > > > OpenBSD 6.8 (GENERIC.MP) guest performance (time ./test-build.sh) > > good: 0m13.54s real 0m10.51s user 0m10.96s system > > bad : 6m20.07s real 11m42.93s user 0m13.57s system > > > > bisected to first bad commit: > > 6b82ef2c9cf18a48726e4bb359aa9014632f6466 > > > > git bisect log: > > # bad: [e47c4aee5bde03e7018f4fde45ba21028a8f8438] KVM: x86/mmu: > > Rename page_header() to to_shadow_page() # good: > > [01c3b2b5cdae39af8dfcf6e40fdf484ae0e812c5] KVM: SVM: Rename > > svm_nested_virtualize_tpr() to nested_svm_virtualize_tpr() git > > bisect start 'e47c4aee5bde' '01c3b2b5cdae' # bad: > > [ebdb292dac7993425c8e31e2c21c9978e914a676] KVM: x86/mmu: Batch zap > > MMU pages when shrinking the slab git bisect bad > > ebdb292dac7993425c8e31e2c21c9978e914a676 # good: > > [fb58a9c345f645f1774dcf6a36fda169253008ae] KVM: x86/mmu: Optimize > > MMU page cache lookup for fully direct MMUs git bisect good > > fb58a9c345f645f1774dcf6a36fda169253008ae # bad: > > [6b82ef2c9cf18a48726e4bb359aa9014632f6466] KVM: x86/mmu: Batch zap > > MMU pages when recycling oldest pages git bisect bad > > 6b82ef2c9cf18a48726e4bb359aa9014632f6466 # good: > > [f95eec9bed76d42194c23153cb1cc8f186bf91cb] KVM: x86/mmu: Don't put > > invalid SPs back on the list of active pages git bisect good > > f95eec9bed76d42194c23153cb1cc8f186bf91cb # first bad commit: > > [6b82ef2c9cf18a48726e4bb359aa9014632f6466] KVM: x86/mmu: Batch zap > > MMU pages when recycling oldest pages > > > > Host machine is old Intel Core2 without EPT (TDP). > > > > TIA, Z. > > Hi, with v5.10-rc6: > get_mmio_spte: detect reserved bits on spte, addr 0xfe00d000, dump > hierarchy: ------ spte 0x8000030e level 3. > ------ spte 0xaf82027 level 2. > ------ spte 0x2038001ffe00d407 level 1. > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 355 at kvm_mmu_page_fault.cold+0x42/0x4f [kvm] > ... > CPU: 1 PID: 355 Comm: qemu-build Not tainted 5.10.0-rc6-amd64 #1 > Hardware name: /DG35EC, BIOS ECG3510M.86A.0118.2010.0113.1426 > 01/13/2010 RIP: 0010:kvm_mmu_page_fault.cold+0x42/0x4f [kvm] > Code: e2 ec 44 8b 04 24 8b 5c 24 0c 44 89 c5 89 da 83 eb 01 48 c7 c7 > 20 b2 65 c0 48 63 c3 48 8b 74 c4 30 e8 dd 74 e2 ec 39 dd 7e e3 <0f> > 0b 41 b8 ea ff ff ff e9 27 99 ff ff 0f 0b 48 8b 54 24 10 48 83 RSP: > 0018:ffffb67400653d30 EFLAGS: 00010202 RAX: 0000000000000027 RBX: > 0000000000000000 RCX: ffffa271ff2976f8 RDX: 00000000ffffffd8 RSI: > 0000000000000027 RDI: ffffa271ff2976f0 RBP: 0000000000000001 R08: > ffffffffadd02ae8 R09: 0000000000000003 R10: 00000000ffffe000 R11: > 3fffffffffffffff R12: 00000000fe00d000 R13: 0000000000000000 R14: > 0000000000000000 R15: 0000000000000001 FS: 00007fc10ae3d640(0000) > GS:ffffa271ff280000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 > ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: > 0000000002dc2000 CR4: 00000000000026e0 Call Trace: > kvm_arch_vcpu_ioctl_run+0xbaf/0x18f0 [kvm] ? do_futex+0x7c4/0xb80 > kvm_vcpu_ioctl+0x203/0x520 [kvm] > ? set_next_entity+0x5b/0x80 > ? __switch_to_asm+0x32/0x60 > ? finish_task_switch+0x70/0x260 > __x64_sys_ioctl+0x338/0x720 > ? __x64_sys_futex+0x120/0x190 > do_syscall_64+0x33/0x40 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x7fc10c389f6b > Code: 89 d8 49 8d 3c 1c 48 f7 d8 49 39 c4 72 b5 e8 1c ff ff ff 85 c0 > 78 ba 4c 89 e0 5b 5d 41 5c c3 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> > 3d 01 f0 ff ff 73 01 c3 48 8b 0d d5 ae 0c 00 f7 d8 64 89 01 48 RSP: > 002b:00007fc10ae3c628 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 000000000000ae80 RCX: 00007fc10c389f6b > RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000012 > RBP: 000055ad3767baf0 R08: 000055ad36be4850 R09: 00000000000000ff > R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 > R13: 000055ad371d9800 R14: 0000000000000001 R15: 0000000000000002 > ---[ end trace c5f7ae690f5abcc4 ]--- > > without: kvm: x86/mmu: Fix get_mmio_spte() on CPUs supporting 5-level > PT I can run guest again, but with degraded performance as before. > > Z. With: KVM: x86/mmu: Bug fixes and cleanups in get_mmio_spte() series I can run guest again and performance is slightly better: v5.8: 0m13.54s real 0m10.51s user 0m10.96s system v5.9: 6m20.07s real 11m42.93s user 0m13.57s system v5.10+fixes: 5m50.77s real 10m38.29s user 0m15.96s system perf top from host when guest (openbsd) is compiling: 26.85% [kernel] [k] queued_spin_lock_slowpath 8.49% [kvm] [k] mmu_page_zap_pte 7.47% [kvm] [k] __kvm_mmu_prepare_zap_page 3.61% [kernel] [k] clear_page_rep 2.43% [kernel] [k] page_counter_uncharge 2.30% [kvm] [k] paging64_page_fault 2.03% [kvm_intel] [k] vmx_vcpu_run 2.02% [kvm] [k] kvm_vcpu_gfn_to_memslot 1.95% [kernel] [k] internal_get_user_pages_fast 1.64% [kvm] [k] kvm_mmu_get_page 1.55% [kernel] [k] page_counter_try_charge 1.33% [kernel] [k] propagate_protected_usage 1.29% [kvm] [k] kvm_arch_vcpu_ioctl_run 1.13% [kernel] [k] get_page_from_freelist 1.01% [kvm] [k] paging64_walk_addr_generic 0.83% [kernel] [k] ___slab_alloc.constprop.0 0.83% [kernel] [k] kmem_cache_free 0.82% [kvm] [k] __pte_list_remove 0.77% [kernel] [k] try_grab_compound_head 0.76% [kvm_intel] [k] 0x000000000001cfa0 0.74% [kvm] [k] pte_list_add HTH, Z.
