On Sat, 27 May 2023, Mike Larkin wrote:
On Fri, May 26, 2023 at 08:14:23PM +0200, br...@mailbox.org wrote:
On 05/26/2023 8:08 PM CEST Mike Larkin <mlar...@nested.page> wrote:
On Fri, May 26, 2023 at 07:16:09PM +0200, br...@mailbox.org wrote:
On 05/26/2023 6:06 PM CEST Mike Larkin <mlar...@nested.page> wrote:
perf top on the linux side to see where qemu is spending it's time?
Sure, I ran `perf top -p $PID` with $PID being the PID of the QEMU process and
copied the screen after a few seconds. Let me know if you intended something
different:
PerfTop: 133 irqs/sec kernel:72.9% exact: 0.0% lost: 0/0 drop: 0/0
[4000Hz cycles], (target_pid: 9939)
--------------------------------------------------------------------------------------------------------------------------------------------------
25.35% [kvm_amd] [k] svm_vcpu_run
4.18% [kernel] [k] native_write_msr
4.01% [kernel] [k] native_read_msr
3.73% [kernel] [k] read_tsc
3.64% [kvm] [k] kvm_arch_vcpu_ioctl_run
2.21% [kvm_amd] [k] svm_vcpu_load
1.98% [kernel] [k] ktime_get
1.47% [kvm] [k] kvm_apic_has_interrupt
1.40% [kernel] [k] restore_fpregs_from_fpstate
1.29% [kvm] [k] apic_has_interrupt_for_ppr
1.18% [kernel] [k] check_preemption_disabled
1.10% [kernel] [k] x86_pmu_disable_all
1.07% [kernel] [k] __srcu_read_lock
1.07% [kernel] [k] newidle_balance
1.03% [kvm] [k] kvm_pmu_trigger_event
0.98% [kernel] [k] amd_pmu_addr_offset
I tried this also on the FreeBSD VM and the irqs/sec were between 2 and 4.
you might just be bombarded with ipis. how many vcpus?
It should be 16, I use `-smp 16 -cpu host`
try with less and see if that works.
With -smp 4 it's better although still worse than FreeBSD/Linux. In htop
OpenBSD is in the 1.3-2.6% range while the other OSes are at 0-0.7%. As I
said, the FreeBSD/Linux VMs continue to stay in the 0% even at -smp 16,
while I've seen OpenBSD idle at up to 7-8% with that.
