Adding a new VFS Lttng module for performance testing

[deanraccoon]

I think syscalls only works for local file system. When I was tuning
the samba ceph/glusterfs module.
 Neither systemtap nor bpf could help me. So I wrote this Lttng module
to measure the elapsed time of the userspace code.

Ralph Böhme <slow at samba.org> 于2018年10月22日周一 下午10:08写道：
>
> On Mon, Oct 22, 2018 at 10:16:08AM +0800, deanraccoon via samba-technical wrote:
> >dear list
> >    I have submit a patch:
> >https://github.com/samba-team/samba/pull/205/
> >   This will help the performace test, Could someone review it ?
>
> I wonder whether this buys us anything a Systemtap (or the upcoming bpftrace)
> script wouln't be able to get us without requiring a VFS module?
>
> Most VFS functions are just abstractions for syscalls, so tracing those is a no
> brainer. Stuff like create_file will require debuginfo, but then again debuginfo
> is needed anyway for (postmortem) diagnosis.
>
> Just wondering...
>
> -slow
>
> --
> Ralph Boehme, Samba Team       https://samba.org/
> Samba Developer, SerNet GmbH   https://sernet.de/en/samba/
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