[libvirt] [PATCH 00/13] Add multiple trace backend function and add new ftrace backend for libvirt

[Daniel P. Berrange]

On Mon, Mar 10, 2014 at 08:17:21AM +0000, yangzy.fnst at cn.fujitsu.com wrote:
> From: Xinghai Yu <yuxinghai at cn.fujitsu.com>
> 
> This patch set will let libvirt to support multiple trace backend function
> and add a new 'ftrace' backend at the same time.
> Then, libvirt would have 2 trace backend: dtrace, ftrace.They can be used
> alone or together.
> 
> Patchs 1,2,3,4,5 are used for supporting multiple trace backend function.
> Patch 6 are used for adding ftrace as a new trace backend for libvirt.
> Patchs 7,8,9,10,11,12,13 add ftrace initial code in programs who use it.
> 
> Thanks very much for Stefan Hajnoczi for I have used his scripts in patch 
> 4 which commited in qemu.
> Thanks very much for Eiichi Tsukata for I have used his ftrace codes in 
> patch 6 which commited in qemu.
> 
> Backgroud:
> The existing trace mechanism in libvirt is dtrace. Although the dtrace
> can work, it's not work well enough. Every time we want get information
> from the trace point we must write a systemtap script and run it
> together with libvirt.
> 
> That's really unpractical on some occasion, especially on production
> server since the systemtap script can't be executed automatically.
> And some problems may be not easy to reproduce, then it will cost a
> lot of time to get the trace information again.
> 
> So I think it is essential to add supporting for record the trace
> information automatically in libvirt to satisfy the user's requirement.
> That's why I implemented multiple trace backend function and ftrace 
> support in libvirt.

FYI, i've put this on my todo list to review. From a quick glance
through there's a few things in here that I'm not liking very
much, but I'll need to take take to analyse them in more detail

Regards,
Daniel
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