Re: [PATCH] clocksource: disable irq when holding watchdog_lock.
From: Tetsuo Handa
Date: Tue Oct 24 2023 - 10:52:38 EST
On 2023/10/24 22:00, Thomas Gleixner wrote:
> Interesting. Can you please tell what the replacement clocksource is
> when the TSC is disabled?
Where can I find the replacement clocksource from?
This slowdown is timing dependent. The same kernel can sometimes boot without slowdown.
I put a small kernel config at https://I-love.SAKURA.ne.jp/tmp/config-6.6-rc7 .
---------- bad case ----------
[ 0.000000][ T0] Linux version 6.6.0-rc7+ (root@ubuntu) (gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0, GNU ld (GNU Binutils for Ubuntu) 2.38) #1055 SMP PREEMPT_DYNAMIC Tue Oct 24 14:20:03 UTC 2023
[ 0.000000][ T0] Command line: BOOT_IMAGE=/boot/vmlinuz-6.6.0-rc7+ root=UUID=a2500e32-bbc8-4f32-bf86-94a6ae160b4b ro lsm=bpf console=ttyS0,115200n8 console=tty0
[ 0.000000][ T0] KERNEL supported cpus:
[ 0.000000][ T0] Intel GenuineIntel
[ 0.000000][ T0] AMD AuthenticAMD
[ 0.000000][ T0] Hygon HygonGenuine
[ 0.000000][ T0] Centaur CentaurHauls
[ 0.000000][ T0] zhaoxin Shanghai
[ 0.000000][ T0] BIOS-provided physical RAM map:
[ 0.000000][ T0] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
[ 0.000000][ T0] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
[ 0.000000][ T0] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
[ 0.000000][ T0] BIOS-e820: [mem 0x0000000000100000-0x00000000dffeffff] usable
[ 0.000000][ T0] BIOS-e820: [mem 0x00000000dfff0000-0x00000000dfffffff] ACPI data
[ 0.000000][ T0] BIOS-e820: [mem 0x00000000fec00000-0x00000000fec00fff] reserved
[ 0.000000][ T0] BIOS-e820: [mem 0x00000000fee00000-0x00000000fee00fff] reserved
[ 0.000000][ T0] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
[ 0.000000][ T0] BIOS-e820: [mem 0x0000000100000000-0x000000019fffffff] usable
[ 0.000000][ T0] NX (Execute Disable) protection: active
[ 0.000000][ T0] APIC: Static calls initialized
[ 0.000000][ T0] SMBIOS 2.5 present.
[ 0.000000][ T0] DMI: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 0.000000][ T0] Hypervisor detected: KVM
[ 0.000000][ T0] kvm-clock: Using msrs 4b564d01 and 4b564d00
[ 0.000000][ T0] kvm-clock: using sched offset of 4651200357824 cycles
[ 0.000002][ T0] clocksource: kvm-clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns
[ 0.000004][ T0] tsc: Detected 2611.208 MHz processor
[ 0.001251][ T0] last_pfn = 0x1a0000 max_arch_pfn = 0x400000000
[ 0.001265][ T0] MTRRs disabled by BIOS
[ 0.001267][ T0] x86/PAT: Configuration [0-7]: WB WC UC- UC WB WP UC- WT
[ 0.001290][ T0] last_pfn = 0xdfff0 max_arch_pfn = 0x400000000
[ 0.001329][ T0] found SMP MP-table at [mem 0x0009fff0-0x0009ffff]
[ 0.001340][ T0] Incomplete global flushes, disabling PCID
[ 0.001500][ T0] RAMDISK: [mem 0x35563000-0x36aa8fff]
[ 0.001509][ T0] No NUMA configuration found
[ 0.001510][ T0] Faking a node at [mem 0x0000000000000000-0x000000019fffffff]
[ 0.001515][ T0] NODE_DATA(0) allocated [mem 0x19ffda000-0x19fffbfff]
[ 0.001676][ T0] Zone ranges:
[ 0.001677][ T0] DMA [mem 0x0000000000001000-0x0000000000ffffff]
[ 0.001678][ T0] DMA32 [mem 0x0000000001000000-0x00000000ffffffff]
[ 0.001679][ T0] Normal [mem 0x0000000100000000-0x000000019fffffff]
[ 0.001680][ T0] Movable zone start for each node
[ 0.001681][ T0] Early memory node ranges
[ 0.001681][ T0] node 0: [mem 0x0000000000001000-0x000000000009efff]
[ 0.001682][ T0] node 0: [mem 0x0000000000100000-0x00000000dffeffff]
[ 0.001683][ T0] node 0: [mem 0x0000000100000000-0x000000019fffffff]
[ 0.001683][ T0] Initmem setup node 0 [mem 0x0000000000001000-0x000000019fffffff]
[ 0.001686][ T0] On node 0, zone DMA: 1 pages in unavailable ranges
[ 0.001738][ T0] On node 0, zone DMA: 97 pages in unavailable ranges
[ 0.011334][ T0] On node 0, zone Normal: 16 pages in unavailable ranges
[ 0.011338][ T0] Intel MultiProcessor Specification v1.4
[ 0.011341][ T0] MPTABLE: OEM ID: VBOXCPU
[ 0.011342][ T0] MPTABLE: Product ID: VirtualBox
[ 0.011342][ T0] MPTABLE: APIC at: 0xFEE00000
[ 0.011403][ T0] Processor #0 (Bootup-CPU)
[ 0.011404][ T0] Processor #1
[ 0.011405][ T0] Processor #2
[ 0.011405][ T0] Processor #3
[ 0.011405][ T0] Processor #4
[ 0.011406][ T0] Processor #5
[ 0.011406][ T0] Processor #6
[ 0.011406][ T0] Processor #7
[ 0.011558][ T0] IOAPIC[0]: apic_id 0, version 32, address 0xfec00000, GSI 0-23
[ 0.011560][ T0] Processors: 8
[ 0.011561][ T0] smpboot: Allowing 8 CPUs, 0 hotplug CPUs
[ 0.011738][ T0] [mem 0xe0000000-0xfebfffff] available for PCI devices
[ 0.011739][ T0] Booting paravirtualized kernel on KVM
[ 0.011740][ T0] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 1910969940391419 ns
[ 0.011744][ T0] setup_percpu: NR_CPUS:8192 nr_cpumask_bits:8 nr_cpu_ids:8 nr_node_ids:1
[ 0.012191][ T0] percpu: Embedded 43 pages/cpu s147032 r0 d29096 u262144
[ 0.012323][ T0] kvm-guest: PV spinlocks enabled
[ 0.012324][ T0] PV qspinlock hash table entries: 256 (order: 0, 4096 bytes, linear)
[ 0.012328][ T0] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-6.6.0-rc7+ root=UUID=a2500e32-bbc8-4f32-bf86-94a6ae160b4b ro lsm=bpf console=ttyS0,115200n8 console=tty0
[ 0.012344][ T0] Unknown kernel command line parameters "BOOT_IMAGE=/boot/vmlinuz-6.6.0-rc7+ lsm=bpf", will be passed to user space.
[ 0.012359][ T0] random: crng init done
[ 0.012937][ T0] Dentry cache hash table entries: 1048576 (order: 11, 8388608 bytes, linear)
[ 0.013283][ T0] Inode-cache hash table entries: 524288 (order: 10, 4194304 bytes, linear)
[ 0.013400][ T0] Fallback order for Node 0: 0
[ 0.013403][ T0] Built 1 zonelists, mobility grouping on. Total pages: 1548016
[ 0.013403][ T0] Policy zone: Normal
[ 0.013407][ T0] mem auto-init: stack:off, heap alloc:on, heap free:off
[ 0.013409][ T0] software IO TLB: area num 8.
[ 0.034155][ T0] Memory: 6067192K/6291000K available (6144K kernel code, 7969K rwdata, 1888K rodata, 2240K init, 4064K bss, 223548K reserved, 0K cma-reserved)
[ 0.034284][ T0] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=8, Nodes=1
[ 0.034321][ T0] Dynamic Preempt: full
[ 0.034347][ T0] rcu: Preemptible hierarchical RCU implementation.
[ 0.034348][ T0] rcu: RCU restricting CPUs from NR_CPUS=8192 to nr_cpu_ids=8.
[ 0.034349][ T0] rcu: RCU calculated value of scheduler-enlistment delay is 100 jiffies.
[ 0.034350][ T0] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=8
[ 0.034398][ T0] NR_IRQS: 4352, nr_irqs: 104, preallocated irqs: 16
[ 0.034655][ T0] rcu: srcu_init: Setting srcu_struct sizes based on contention.
[ 0.062932][ T0] Console: colour VGA+ 80x25
[ 0.062937][ T0] printk: console [tty0] enabled
[ 0.201799][ T0] printk: console [ttyS0] enabled
[ 0.347985][ T0] APIC: Switch to symmetric I/O mode setup
[ 0.358057][ T0] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
[ 0.361420][ T0] clocksource: tsc-early: mask: 0xffffffffffffffff max_cycles: 0x25a39815946, max_idle_ns: 440795282683 ns
[ 0.366555][ T0] Calibrating delay loop (skipped) preset value.. 5222.41 BogoMIPS (lpj=2611208)
[ 0.367549][ T0] Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0
[ 0.368557][ T0] Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0, 1GB 0
[ 0.370554][ T0] Spectre V1 : Mitigation: usercopy/swapgs barriers and __user pointer sanitization
[ 0.372552][ T0] Spectre V2 : Mitigation: Enhanced / Automatic IBRS
[ 0.374551][ T0] Spectre V2 : Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch
[ 0.376551][ T0] Spectre V2 : Spectre v2 / PBRSB-eIBRS: Retire a single CALL on VMEXIT
[ 0.378552][ T0] RETBleed: Mitigation: Enhanced IBRS
[ 0.380551][ T0] Speculative Store Bypass: Vulnerable
[ 0.382553][ T0] x86/fpu: x87 FPU will use FXSAVE
[ 0.391441][ T0] Freeing SMP alternatives memory: 16K
[ 0.392553][ T0] pid_max: default: 32768 minimum: 301
[ 0.394628][ T0] Mount-cache hash table entries: 16384 (order: 5, 131072 bytes, linear)
[ 0.396566][ T0] Mountpoint-cache hash table entries: 16384 (order: 5, 131072 bytes, linear)
[ 0.601817][ T1] smpboot: CPU0: 12th Gen Intel(R) Core(TM) i7-1255U (family: 0x6, model: 0x9a, stepping: 0x4)
[ 0.603653][ T1] Performance Events: unsupported p6 CPU model 154 no PMU driver, software events only.
[ 0.605559][ T1] signal: max sigframe size: 1440
[ 0.607568][ T1] rcu: Hierarchical SRCU implementation.
[ 0.609550][ T1] rcu: Max phase no-delay instances is 400.
[ 0.611622][ T1] NMI watchdog: Perf NMI watchdog permanently disabled
[ 0.613627][ T1] smp: Bringing up secondary CPUs ...
[ 0.616629][ T1] smpboot: x86: Booting SMP configuration:
[ 0.619552][ T1] .... node #0, CPUs: #1 #2 #3 #4 #5 #6 #7
[ 0.624549][ C0] TSC synchronization [CPU#0 -> CPU#1]:
[ 0.624549][ C0] Measured 112923 cycles TSC warp between CPUs, turning off TSC clock.
[ 0.624549][ T8] tsc: Marking TSC unstable due to check_tsc_sync_source failed
[ 11.793585][ T1] smp: Brought up 1 node, 8 CPUs
[ 22.463567][ T1] smpboot: Max logical packages: 1
[ 26.831718][ T1] smpboot: Total of 8 processors activated (41779.32 BogoMIPS)
(...too slow to wait...)
---------- bad case ----------
---------- another bad case (the same kernel, different try) ----------
(...snipped...)
[ 0.624575][ T1] smp: Bringing up secondary CPUs ...
[ 0.624575][ T1] smpboot: x86: Booting SMP configuration:
[ 0.624575][ T1] .... node #0, CPUs: #1 #2 #3 #4 #5 #6 #7
[ 0.626575][ C0] TSC synchronization [CPU#0 -> CPU#1]:
[ 0.626575][ C0] Measured 61974 cycles TSC warp between CPUs, turning off TSC clock.
[ 0.626575][ T8] tsc: Marking TSC unstable due to check_tsc_sync_source failed
[ 20.677606][ T1] smp: Brought up 1 node, 8 CPUs
[ 31.942609][ T1] smpboot: Max logical packages: 1
[ 46.890605][ T1] smpboot: Total of 8 processors activated (41779.32 BogoMIPS)
(...too slow to wait...)
---------- another bad case ----------
---------- good case (the same kernel, different try) ----------
[ 0.000000][ T0] Linux version 6.6.0-rc7+ (root@ubuntu) (gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0, GNU ld (GNU Binutils for Ubuntu) 2.38) #1055 SMP PREEMPT_DYNAMIC Tue Oct 24 14:20:03 UTC 2023
[ 0.000000][ T0] Command line: BOOT_IMAGE=/boot/vmlinuz-6.6.0-rc7+ root=UUID=a2500e32-bbc8-4f32-bf86-94a6ae160b4b ro lsm=bpf console=ttyS0,115200n8 console=tty0
[ 0.000000][ T0] KERNEL supported cpus:
[ 0.000000][ T0] Intel GenuineIntel
[ 0.000000][ T0] AMD AuthenticAMD
[ 0.000000][ T0] Hygon HygonGenuine
[ 0.000000][ T0] Centaur CentaurHauls
[ 0.000000][ T0] zhaoxin Shanghai
[ 0.000000][ T0] BIOS-provided physical RAM map:
[ 0.000000][ T0] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
[ 0.000000][ T0] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
[ 0.000000][ T0] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
[ 0.000000][ T0] BIOS-e820: [mem 0x0000000000100000-0x00000000dffeffff] usable
[ 0.000000][ T0] BIOS-e820: [mem 0x00000000dfff0000-0x00000000dfffffff] ACPI data
[ 0.000000][ T0] BIOS-e820: [mem 0x00000000fec00000-0x00000000fec00fff] reserved
[ 0.000000][ T0] BIOS-e820: [mem 0x00000000fee00000-0x00000000fee00fff] reserved
[ 0.000000][ T0] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
[ 0.000000][ T0] BIOS-e820: [mem 0x0000000100000000-0x000000019fffffff] usable
[ 0.000000][ T0] NX (Execute Disable) protection: active
[ 0.000000][ T0] APIC: Static calls initialized
[ 0.000000][ T0] SMBIOS 2.5 present.
[ 0.000000][ T0] DMI: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 0.000000][ T0] Hypervisor detected: KVM
[ 0.000000][ T0] kvm-clock: Using msrs 4b564d01 and 4b564d00
[ 0.000002][ T0] kvm-clock: using sched offset of 189117280516 cycles
[ 0.000004][ T0] clocksource: kvm-clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns
[ 0.000006][ T0] tsc: Detected 2611.208 MHz processor
[ 0.001341][ T0] last_pfn = 0x1a0000 max_arch_pfn = 0x400000000
[ 0.001356][ T0] MTRRs disabled by BIOS
[ 0.001358][ T0] x86/PAT: Configuration [0-7]: WB WC UC- UC WB WP UC- WT
[ 0.001367][ T0] last_pfn = 0xdfff0 max_arch_pfn = 0x400000000
[ 0.001409][ T0] found SMP MP-table at [mem 0x0009fff0-0x0009ffff]
[ 0.001422][ T0] Incomplete global flushes, disabling PCID
[ 0.001559][ T0] RAMDISK: [mem 0x35563000-0x36aa8fff]
[ 0.001568][ T0] No NUMA configuration found
[ 0.001568][ T0] Faking a node at [mem 0x0000000000000000-0x000000019fffffff]
[ 0.001573][ T0] NODE_DATA(0) allocated [mem 0x19ffda000-0x19fffbfff]
[ 0.001704][ T0] Zone ranges:
[ 0.001704][ T0] DMA [mem 0x0000000000001000-0x0000000000ffffff]
[ 0.001706][ T0] DMA32 [mem 0x0000000001000000-0x00000000ffffffff]
[ 0.001707][ T0] Normal [mem 0x0000000100000000-0x000000019fffffff]
[ 0.001707][ T0] Movable zone start for each node
[ 0.001708][ T0] Early memory node ranges
[ 0.001709][ T0] node 0: [mem 0x0000000000001000-0x000000000009efff]
[ 0.001709][ T0] node 0: [mem 0x0000000000100000-0x00000000dffeffff]
[ 0.001710][ T0] node 0: [mem 0x0000000100000000-0x000000019fffffff]
[ 0.001711][ T0] Initmem setup node 0 [mem 0x0000000000001000-0x000000019fffffff]
[ 0.001714][ T0] On node 0, zone DMA: 1 pages in unavailable ranges
[ 0.001738][ T0] On node 0, zone DMA: 97 pages in unavailable ranges
[ 0.011645][ T0] On node 0, zone Normal: 16 pages in unavailable ranges
[ 0.011651][ T0] Intel MultiProcessor Specification v1.4
[ 0.011653][ T0] MPTABLE: OEM ID: VBOXCPU
[ 0.011654][ T0] MPTABLE: Product ID: VirtualBox
[ 0.011654][ T0] MPTABLE: APIC at: 0xFEE00000
[ 0.011736][ T0] Processor #0 (Bootup-CPU)
[ 0.011737][ T0] Processor #1
[ 0.011738][ T0] Processor #2
[ 0.011738][ T0] Processor #3
[ 0.011738][ T0] Processor #4
[ 0.011739][ T0] Processor #5
[ 0.011739][ T0] Processor #6
[ 0.011739][ T0] Processor #7
[ 0.011914][ T0] IOAPIC[0]: apic_id 0, version 32, address 0xfec00000, GSI 0-23
[ 0.011917][ T0] Processors: 8
[ 0.011918][ T0] smpboot: Allowing 8 CPUs, 0 hotplug CPUs
[ 0.012112][ T0] [mem 0xe0000000-0xfebfffff] available for PCI devices
[ 0.012113][ T0] Booting paravirtualized kernel on KVM
[ 0.012115][ T0] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 1910969940391419 ns
[ 0.012119][ T0] setup_percpu: NR_CPUS:8192 nr_cpumask_bits:8 nr_cpu_ids:8 nr_node_ids:1
[ 0.012381][ T0] percpu: Embedded 43 pages/cpu s147032 r0 d29096 u262144
[ 0.012533][ T0] kvm-guest: PV spinlocks enabled
[ 0.012534][ T0] PV qspinlock hash table entries: 256 (order: 0, 4096 bytes, linear)
[ 0.012539][ T0] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-6.6.0-rc7+ root=UUID=a2500e32-bbc8-4f32-bf86-94a6ae160b4b ro lsm=bpf console=ttyS0,115200n8 console=tty0
[ 0.012557][ T0] Unknown kernel command line parameters "BOOT_IMAGE=/boot/vmlinuz-6.6.0-rc7+ lsm=bpf", will be passed to user space.
[ 0.012574][ T0] random: crng init done
[ 0.013371][ T0] Dentry cache hash table entries: 1048576 (order: 11, 8388608 bytes, linear)
[ 0.013777][ T0] Inode-cache hash table entries: 524288 (order: 10, 4194304 bytes, linear)
[ 0.013889][ T0] Fallback order for Node 0: 0
[ 0.013892][ T0] Built 1 zonelists, mobility grouping on. Total pages: 1548016
[ 0.013893][ T0] Policy zone: Normal
[ 0.013896][ T0] mem auto-init: stack:off, heap alloc:on, heap free:off
[ 0.013897][ T0] software IO TLB: area num 8.
[ 0.035006][ T0] Memory: 6067192K/6291000K available (6144K kernel code, 7969K rwdata, 1888K rodata, 2240K init, 4064K bss, 223548K reserved, 0K cma-reserved)
[ 0.035165][ T0] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=8, Nodes=1
[ 0.035212][ T0] Dynamic Preempt: full
[ 0.035244][ T0] rcu: Preemptible hierarchical RCU implementation.
[ 0.035245][ T0] rcu: RCU restricting CPUs from NR_CPUS=8192 to nr_cpu_ids=8.
[ 0.035246][ T0] rcu: RCU calculated value of scheduler-enlistment delay is 100 jiffies.
[ 0.035247][ T0] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=8
[ 0.035309][ T0] NR_IRQS: 4352, nr_irqs: 104, preallocated irqs: 16
[ 0.035572][ T0] rcu: srcu_init: Setting srcu_struct sizes based on contention.
[ 0.066412][ T0] Console: colour VGA+ 80x25
[ 0.066416][ T0] printk: console [tty0] enabled
[ 0.206184][ T0] printk: console [ttyS0] enabled
[ 0.355879][ T0] APIC: Switch to symmetric I/O mode setup
[ 0.365732][ T0] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
[ 0.368881][ T0] clocksource: tsc-early: mask: 0xffffffffffffffff max_cycles: 0x25a39815946, max_idle_ns: 440795282683 ns
[ 0.373903][ T0] Calibrating delay loop (skipped) preset value.. 5222.41 BogoMIPS (lpj=2611208)
[ 0.377974][ T0] Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0
[ 0.379900][ T0] Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0, 1GB 0
[ 0.381903][ T0] Spectre V1 : Mitigation: usercopy/swapgs barriers and __user pointer sanitization
[ 0.383901][ T0] Spectre V2 : Mitigation: Enhanced / Automatic IBRS
[ 0.385900][ T0] Spectre V2 : Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch
[ 0.387900][ T0] Spectre V2 : Spectre v2 / PBRSB-eIBRS: Retire a single CALL on VMEXIT
[ 0.389900][ T0] RETBleed: Mitigation: Enhanced IBRS
[ 0.391900][ T0] Speculative Store Bypass: Vulnerable
[ 0.394902][ T0] x86/fpu: x87 FPU will use FXSAVE
[ 0.403537][ T0] Freeing SMP alternatives memory: 16K
[ 0.404902][ T0] pid_max: default: 32768 minimum: 301
[ 0.406940][ T0] Mount-cache hash table entries: 16384 (order: 5, 131072 bytes, linear)
[ 0.409131][ T0] Mountpoint-cache hash table entries: 16384 (order: 5, 131072 bytes, linear)
[ 0.617243][ T1] smpboot: CPU0: 12th Gen Intel(R) Core(TM) i7-1255U (family: 0x6, model: 0x9a, stepping: 0x4)
[ 0.617898][ T1] Performance Events: unsupported p6 CPU model 154 no PMU driver, software events only.
[ 0.617898][ T1] signal: max sigframe size: 1440
[ 0.617898][ T1] rcu: Hierarchical SRCU implementation.
[ 0.617898][ T1] rcu: Max phase no-delay instances is 400.
[ 0.617898][ T1] NMI watchdog: Perf NMI watchdog permanently disabled
[ 0.617898][ T1] smp: Bringing up secondary CPUs ...
[ 0.617898][ T1] smpboot: x86: Booting SMP configuration:
[ 0.617898][ T1] .... node #0, CPUs: #1 #2 #3 #4 #5 #6 #7
[ 0.620898][ C0] TSC synchronization [CPU#0 -> CPU#1]:
[ 0.620898][ C0] Measured 61957 cycles TSC warp between CPUs, turning off TSC clock.
[ 0.620898][ T8] tsc: Marking TSC unstable due to check_tsc_sync_source failed
[ 0.856914][ T1] smp: Brought up 1 node, 8 CPUs
[ 0.910911][ T1] smpboot: Max logical packages: 1
[ 1.041908][ T1] smpboot: Total of 8 processors activated (41779.32 BogoMIPS)
[ 1.051188][ T1] devtmpfs: initialized
[ 1.210943][ T1] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 1911260446275000 ns
[ 1.234916][ T1] futex hash table entries: 2048 (order: 5, 131072 bytes, linear)
[ 1.530084][ T1] cpuidle: using governor ladder
[ 1.531920][ T1] cpuidle: using governor menu
[ 1.577978][ T1] iommu: Default domain type: Translated
[ 1.579900][ T1] iommu: DMA domain TLB invalidation policy: lazy mode
[ 1.585010][ T1] clocksource: Switched to clocksource kvm-clock
[ 1.626044][ T1] PCI-DMA: Using software bounce buffering for IO (SWIOTLB)
[ 1.626972][ T1] software IO TLB: mapped [mem 0x00000000dbff0000-0x00000000dfff0000] (64MB)
[ 1.626972][ T1] platform rtc_cmos: registered platform RTC device (no PNP device found)
(...snipped...)
---------- good case ----------