Unnecessary events option of the trace argument with UST backend

[Francis Deslauriers]

When running configure with the --enable-trace-backends=ust option and compiling.
The user should not have to specify a the "events" and "file" options because they are not used with that tracing framework.

Right now, in order the use this option the need to specify a dummy events file.

This fails:
$> qemu-system-x86_64 -hda debian_wheezy_amd64_standard.qcow2 -trace -m 512
qemu-system-x86_64: -trace -m: Invalid parameter '-m'

This works:
$> qemu-system-x86_64 -hda debian_wheezy_amd64_standard.qcow2 -trace events=dummy-events.txt -m 512
VNC server running on `127.0.0.1:5900'

I am using version:
$> qemu-system-x86_64 --version
QEMU emulator version 2.1.90, Copyright (c) 2003-2008 Fabrice Bellard

[Stefan Hajnoczi (stefanha)]

On Wed, Nov 12, 2014 at 04:01:38PM -0000, Francis Deslauriers wrote:
> When running configure with the --enable-trace-backends=ust option and compiling.
> The user should not have to specify a the "events" and "file" options because they are not used with that tracing framework.
>
> Right now, in order the use this option the need to specify a dummy
> events file.
>
> This fails:
> $> qemu-system-x86_64 -hda debian_wheezy_amd64_standard.qcow2 -trace -m 512
> qemu-system-x86_64: -trace -m: Invalid parameter '-m'
>
> This works:
> $> qemu-system-x86_64 -hda debian_wheezy_amd64_standard.qcow2 -trace events=dummy-events.txt -m 512
> VNC server running on `127.0.0.1:5900'
>
> I am using version:
> $> qemu-system-x86_64 --version
> QEMU emulator version 2.1.90, Copyright (c) 2003-2008 Fabrice Bellard

What happens when you pass no -trace option?

Stefan

[Francis Deslauriers (fdeslaur)]

It works without the -trace option.

Want I meant with this post is that the "events" argument of the "-trace" option has no effect in the case of using LTTng UST as the tracing backend because the events are enabled from the LTTng tracer itself.

Is there some way I can make an argument optional or conditional to a tracing framework?

Thanks,

Francis

[Thomas Huth (th-huth)]

The QEMU project is currently considering to move its bug tracking to another system. For this we need to know which bugs are still valid and which could be closed already. Thus we are setting older bugs to "Incomplete" now.
If you still think this bug report here is valid, then please switch the state back to "New" within the next 60 days, otherwise this report will be marked as "Expired". Or mark it as "Fix Released" if the problem has been solved with a newer version of QEMU already. Thank you and sorry for the inconvenience.

[Launchpad Janitor (janitor)]

[Expired for QEMU because there has been no activity for 60 days.]