Re: [question] lots of interrupts injected to vm when pressing somekey w/o releasing

["Zhang Haoyu" <zhanghy@sangfor.com>]

>On 20/11/2014 03:20, Zhang Haoyu wrote:
>> Hi all,
>> 
>> If I press the one of "Insert/Delete/Home/End/PageUp/PageDown/UpArrow/
>> DownArrow/LeftArrow/RightArrow" key w/o releasing, then lots of interrupts
>> will be injected to vm(win7/win2008), about 8000/s, the system become very slow,
>> bringing very bad experience. But the other keys are okay.
>> And, linux guest has no this problem.
>
>Do you have a trace for this?  What version of QEMU and what UI backend?
>
Sorry for forgetting to mention test environment from the start.
Host: rhel7 with kernel-3.10.0-121
QEMU: qemu-2.0.2
Guest: win7(bad),win2008(bad),linux-kernel-3.10.0-121(good)

No UI backend, directly start the VM via qemu command.

perf top data when above problem happening: 
   PerfTop:    8710 irqs/sec  kernel:69.5%  exact:  0.0% [4000Hz cycles],  (target_pid: 22382)
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    15.04%  [kernel]                 [k] read_hpet                                  
    11.69%  [kvm_intel]              [k] vmx_vcpu_run                               
     6.99%  [kvm]                    [k] vcpu_enter_guest                           
     5.22%  [kvm]                    [k] kvm_vcpu_on_spin                           
     4.76%  [kernel]                 [k] __srcu_read_lock                           
     4.31%  libglib-2.0.so.0.3200.4  [.] g_hash_table_lookup                        
     3.21%  [kvm_intel]              [k] __vmx_load_host_state                      
     2.60%  libglib-2.0.so.0.3200.4  [.] g_str_hash                                 
     2.49%  [kvm_intel]              [k] vmx_save_host_state                        
     2.07%  qemu-system-x86_64       [.] e1000_txmmio_poll                          
     1.36%  [kernel]                 [k] __srcu_read_unlock                         
     1.24%  libc-2.13.so             [.] 0x00000000000e7582                         
     1.05%  qemu-system-x86_64       [.] start_xmit                                 
     1.04%  [kvm]                    [k] kvm_fast_pio_in_complete_emulated_pio      
     1.04%  [kvm_intel]              [k] vmcs_writel                                
     1.02%  qemu-system-x86_64       [.] vnc_refresh_server_surface                 
     0.99%  [vdso]                   [.] 0x0000000000000847                         
     0.98%  [kernel]                 [k] native_read_tsc                            
     0.93%  [kernel]                 [k] fget_light                                 
     0.85%  [kvm]                    [k] kvm_arch_vcpu_load                         
     0.83%  [kvm_intel]              [k] vmx_cache_reg                              
     0.79%  [kvm]                    [k] kvm_arch_vcpu_ioctl_run                    
     0.73%  qemu-system-x86_64       [.] object_class_dynamic_cast                  
     0.72%  libpthread-2.13.so       [.] pthread_mutex_lock                         
     0.68%  [kvm_intel]              [k] add_atomic_switch_msr                      
     0.63%  [kvm]                    [k] emulator_pio_in_out.isra.101               
     0.62%  [kernel]                 [k] recalc_sigpending                          
     0.61%  qemu-system-x86_64       [.] kvm_cpu_exec                               
     0.59%  qemu-system-x86_64       [.] kvm_arch_post_run                          
     0.58%  [kernel]                 [k] _raw_spin_lock_irq                         
7716 unprocessable samples recorded.

Thanks,
Zhang Haoyu
>Paolo