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

To: "Stefano Stabellini" <stefano.stabellini@xxxxxxxxxxxxx>
Subject: RE: [Xen-devel] throttling logs messages from qemu
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Sat, 1 Aug 2009 11:37:02 +1000
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Thread-topic: [Xen-devel] throttling logs messages from qemu
> On Fri, 31 Jul 2009, James Harper wrote:
> > I see that in 3.4.x, throttling has been changed from a file in /etc
> > 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
> to a bash script that does what you want and then calls qemu-dm with
> 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.

Can we revert the patch then? I assume the citrix version of xend puts
the log-throttling key in based on certain criteria but maybe it isn't
appropriate for the gpl version? I mean it's pretty much useless in this
form isn't it? It worked great for me as detecting the presence of a
file in /etc...



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