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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Fri, 16 Oct 2015 17:27:52 +0200
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Subject: Re: [Qemu-devel] What's the intended use of log.h logging?
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To: Peter Maydell <peter.maydell@linaro.org>
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>



On 16/10/2015 16:31, Peter Maydell wrote:
> > I hadn't thought about levels, but honestly when I use KVM tracing (w=
hich
> > is often measured in tens of megabytes per run) I don't care.
>
> In a lot of cases, especially with the TCG logging, not enabling
> voluminous tracing is really important because if you turn it all
> on then the system is way too slow (and can behave differently
> as a result), and generates gigabytes of trace output. (-d exec
> and -d cpu will do this, for instance.)

Yes, but device models are going to generate orders of magnitude smaller
traces than the CPU.  Since I'm not proposing to drop -d together, but
rather to integrate tracing with it, we can cross that river when we
reach it.

Paolo