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`

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