Re: Re: [PATCH V2 0/5] trace-cmd: Support the feature recordingtrace data of guests on the host

[Yoshihiro YUNOMAE]

Hi Steven,

(2013/10/15 6:26), Steven Rostedt wrote:
> On Fri, 13 Sep 2013 11:06:27 +0900
> Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@xxxxxxxxxxx> wrote:
>
>
> > <How to use>
> > 1. Run virt-server on a host
> >     # trace-cmd virt-server
> >
> > 2. Make guest domain directory
> >     # mkdir -p /tmp/trace-cmd/virt/<domain>
> >     # chmod 710 /tmp/trace-cmd/virt/<domain>
> >     # chgrp qemu /tmp/trace-cmd/virt/<domain>
>
> Quick comment. I think the above should be done by trace-cmd. At least
> have options for it like:
>
> trace-cmd virt-server -d /tmp/trace-cmd/virt/domain -m 710 -g qemu
>
> Perhaps default some of those, and have trace-cmd print out:
>
>    Process Directory:     /tmp/trace-cmd/virt/domain
>    Directory permission:  0710
>    Group:                 qemu

OK. As you say, when we know domains which we will boot, trace-cmd
should make those automatically. So, I'll add this feature.
Note that if we don't know domains when we boot virt-sevrer, we must
make those manually now.

In this patch set, virt-server always uses /tmp/trace-cmd/virt, so
we had better indicate only the domain name with d option, I think.

trace-cmd virt-server -d domain -m 710 -g qemu

What do you think about this?

Thanks,

Yoshihiro YUNOMAE

> OK, now to look at the actual code ;-)
>
> -- Steve
>
>
> > 3. Make FIFO on the host
> >     # mkfifo /tmp/trace-cmd/virt/<domain>/trace-path-cpu{0,1,...,X}.{in,out}
> >
> > 4. Set up of virtio-serial pipe of a guest on the host
> >     Add the following tags to domain XML files.
> >     # virsh edit <domain>
> >     <channel type='unix'>
> >        <source mode='connect' path='/tmp/trace-cmd/virt/agent-ctl-path'/>
> >        <target type='virtio' name='agent-ctl-path'/>
> >     </channel>
> >     <channel type='pipe'>
> >        <source path='/tmp/trace-cmd/virt/<domain>/trace-path-cpu0'/>
> >        <target type='virtio' name='trace-path-cpu0'/>
> >     </channel>
> >     ... (cpu1, cpu2, ...)
> >
> > 5. Boot the guest
> >     # virsh start <domain>
> >
> > 6. Execute "record --virt" on the guest
> >     # trace-cmd record --virt -e sched*
> --
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--
Yoshihiro YUNOMAE
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: yoshihiro.yunomae.ez@xxxxxxxxxxx


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