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Re: [Xen-devel] throttling logs messages from qemu

To: James Harper <james.harper@xxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] throttling logs messages from qemu
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Date: Fri, 31 Jul 2009 14:30:31 +0100
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On Fri, 31 Jul 2009, James Harper wrote:
> I see that in 3.4.x, throttling has been changed from a file in /etc to
> a xenstore entry, as per the following code:
>     throttling = xenstore_vm_read(domid, "log-throttling", &len);
>     if (throttling != NULL) {
>         throttling_disabled = (throttling[0] - '0');
>         free(throttling);
>     }
> A bit of searching tells me that the full path of the key is
> /vm/<uuid>/log-throttling, but it appears to be read at boot. How can I
> get it written in there in time?

Good question :)
You could hack xend but it is not exactly something you want to do.
Another possibility is to change your device_model in the vm config file
to a bash script that does what you want and then calls qemu-dm with the
right arguments.
We could probably modify qemu to read the xenstore key from another
place that is easier to know before the VM is started.

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