Hi Steven,

(2013/10/15 6:26), Steven Rostedt wrote:
> On Fri, 13 Sep 2013 11:06:27 +0900
> Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com> 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@hitachi.com