Re: Windows slow boot: contractor wanted

[Avi Kivity <avi@redhat.com>]

On 08/22/2012 03:40 PM, Richard Davies wrote:
> 
> I can trigger the slow boots without KSM and they have the same profile,
> with _raw_spin_lock_irqsave and isolate_freepages_block at the top.
> 
> I reduced to 3x 20GB 8-core VMs on a 128GB host (rather than 3x 40GB 8-core
> VMs), and haven't managed to get a really slow boot yet (>5 minutes). I'll
> post agan when I get one.

I think you can go higher than that.  But 120GB on a 128GB host is
pushing it.

> 
> In the slowest boot that I have so far (1-2 minutes), this is the perf top
> ouput:
> 
> 
>    PerfTop:   26741 irqs/sec  kernel:97.5%  exact:  0.0% [4000Hz cycles],  (all, 16 CPUs)
> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> 
>     53.94%  [kernel]          [k] clear_page_c
>      2.77%  [kernel]          [k] svm_vcpu_put
>      2.60%  [kernel]          [k] svm_vcpu_run
>      1.79%  [kernel]          [k] sub_preempt_count
>      1.56%  [kernel]          [k] svm_vcpu_load
>      1.44%  [kernel]          [k] __schedule
>      1.36%  [kernel]          [k] kvm_arch_vcpu_ioctl_run
>      1.34%  [kernel]          [k] resched_task
>      1.32%  [kernel]          [k] _raw_spin_lock
>      0.98%  [kernel]          [k] trace_preempt_on
>      0.95%  [kernel]          [k] get_parent_ip
>      0.94%  [kernel]          [k] yield_to


This is pretty normal, Widows is touching memory so clear_page_c() is
called to scrub it.



-- 
error compiling committee.c: too many arguments to function