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From: Peter Maydell <peter.maydell@linaro.org>
Date: Fri, 16 Oct 2015 14:29:17 +0100
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Subject: Re: [Qemu-devel] What's the intended use of log.h logging?
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To: "Daniel P. Berrange" <berrange@redhat.com>
Cc: Pavel Butsykin <pbutsykin@virtuozzo.com>, Markus Armbruster <armbru@redhat.com>, QEMU Developers <qemu-devel@nongnu.org>, Luiz Capitulino <lcapitulino@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, "Denis V. Lunev" <den@openvz.org>, Paolo Bonzini <pbonzini@redhat.com>

On 16 October 2015 at 14:26, Daniel P. Berrange <berrange@redhat.com> wrote:
>> It's also very useful to be able to enable whole *classes* of
>> tracing (like "tell me whenever my guest OS does something dumb");
>> does the tracepoint code have any support for this?
>
> You can use globs in tracepoint names you want to enable. So if the
> tracepoints have structured / well considerd name prefixes, you can
> enable classses at once.

...but in practice we don't really do that very much, and we
don't have documented lists of classes which we support either.
Guessing what might be a plausible glob of tracepoint names to
enable seems like a definite step back from the formalized
logging categories we have currently.

-- PMM