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Re: [Qemu-devel] Re: qemu-kvm hangs if multipath device is queing
From: |
Peter Lieven |
Subject: |
Re: [Qemu-devel] Re: qemu-kvm hangs if multipath device is queing |
Date: |
Sun, 23 May 2010 12:30:30 +0200 |
Am 19.05.2010 um 10:18 schrieb Peter Lieven:
> Kevin Wolf wrote:
>> Am 19.05.2010 09:29, schrieb Christoph Hellwig:
>>
>>> On Tue, May 18, 2010 at 03:22:36PM +0200, Kevin Wolf wrote:
>>>
>>>> I think it's stuck here in an endless loop:
>>>>
>>>> while (laiocb->ret == -EINPROGRESS)
>>>> qemu_laio_completion_cb(laiocb->ctx);
>>>>
>>>> Can you verify this by single-stepping one or two loop iterations? ret
>>>> and errno after the read call could be interesting, too.
>>>>
>>> Maybe the compiler is just too smart. Without some form of barrier
>>> it could just optimize the loop away as laiocb->ret couldn't change
>>> in a normal single-threaded environment.
>>>
>>
>> It probably could in theory, but in practice we're in a read() inside
>> qemu_laio_completion, so it didn't do it here.
>>
> if you supply a patch that will add some usleeps at the point in
> question i'm willing to test if it solves the 100% cpu problem.
can someone help here? what would be the best option to add some
usleeps?
>> Kevin
>>
>>
>
>
>
- Re: [Qemu-devel] Qemu-KVM 0.12.3 and Multipath -> Assertion, (continued)
- qemu-kvm hangs if multipath device is queing (was: Re: [Qemu-devel] Qemu-KVM 0.12.3 and Multipath -> Assertion), Peter Lieven, 2010/05/12
- [Qemu-devel] Re: qemu-kvm hangs if multipath device is queing, Kevin Wolf, 2010/05/14
- [Qemu-devel] Re: qemu-kvm hangs if multipath device is queing, Peter Lieven, 2010/05/18
- [Qemu-devel] Re: qemu-kvm hangs if multipath device is queing, Kevin Wolf, 2010/05/18
- [Qemu-devel] Re: qemu-kvm hangs if multipath device is queing, Christoph Hellwig, 2010/05/19
- [Qemu-devel] Re: qemu-kvm hangs if multipath device is queing, Kevin Wolf, 2010/05/19
- [Qemu-devel] Re: qemu-kvm hangs if multipath device is queing, Peter Lieven, 2010/05/19
- Re: [Qemu-devel] Re: qemu-kvm hangs if multipath device is queing,
Peter Lieven <=
- Re: [Qemu-devel] Qemu-KVM 0.12.3 and Multipath -> Assertion, André Weidemann, 2010/05/08
[Qemu-devel] Re: Qemu-KVM 0.12.3 and Multipath -> Assertion, André Weidemann, 2010/05/04