On Wed, Oct 12, 2011 at 3:52 PM, Jorge Lucangeli Obes
<[email protected]> wrote:
> On Wed, Oct 12, 2011 at 12:55 PM, Alexander Graf <[email protected]> wrote:
>>
>> On 12.10.2011, at 20:49, Jorge Lucangeli Obes wrote:
>>
>>> Hi all,
>>>
>>> I'm working on Chromium OS development. We have a pretty elaborate
>>> chroot inside of which we carry out all development. We use KVM to
>>> launch Chromium OS builds inside a VM for testing. Turns out that for
>>> some reason, when QEMU is launched from inside the chroot, KVM itself
>>> seems not to be used. The VM is extremely slow.
>>>
>>> Is this known/expected? QEMU is installed inside the chroot, the KVM
>>> modules are loaded, the /dev/kvm device is present and accesible. Any
>>> ideas on how to debug this?
>>
>> The first obvious idea I'd have here would be to strace the qemu process and 
>> check what happens when it opens /dev/kvm :)

Resending since original attachment was too large.

> That's what I thought. I did a test run under strace. I'm attaching
> the list of syscalls from the call to 'open(/dev/kvm)' to the first
> successful 'ioctl(KVM_RUN)'. /dev/kvm seems to be opened correctly, a
> VCPU is created, and then that VCPU is used with KVM_RUN. After the
> first call to 'ioctl(KVM_RUN)', there are long lists of more KVM_RUN
> calls, separated by brief groups of other calls. So, IIUC, KVM seems
> to be used, and seems to be "working", but the VM is one order of
> magnitude slower anyways.
>
> Any ideas?

Thanks,
Jorge

Attachment: syscalls
Description: Binary data

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