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

From: Steven Rostedt
Date: Mon Oct 14 2013 - 17:26:46 EST


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, 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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