Re: using SDT events

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Tue, Sep 27, 2016 at 11:40:26AM -0700, Masami Hiramatsu escreveu:
> On Tue, 27 Sep 2016 10:55:38 -0300
> Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> 
> > Masami,
> > 
> > 	Testing something else (event aliases/JSON) I saw the many sdt
> > events available via 'perf list', decided to use the usual workflow,
> > failed, what am I doing wrong?
> 
> No, that is not supported yet. So I dropped perf-list support from
> the latest series...

Ok, I guess I recall that discussion, will add some warning about that
in the 'perf list' output.

- Arnaldo
 
> https://lkml.org/lkml/2016/7/1/133
> 
> The unresolved problems are 
>  - how we treat sdt events after recorded? remove or leave it as tracepoint?
>  - what should be done if we found the tracepoint which has same name of the
>    SDT. (we can not reserve tracepoint name beforehand)
>  - Sometimes SDT name can be conflict, even on same binary.
> 
> 
> > 
> > 
> > [root@jouet ~]# perf list sdt_qemu:pci*
> > 
> > List of pre-defined events (to be used in -e):
> > 
> >   sdt_qemu:pci_cfg_read                              [SDT event]
> >   sdt_qemu:pci_cfg_write                             [SDT event]
> >   sdt_qemu:pci_update_mappings_add                   [SDT event]
> >   sdt_qemu:pci_update_mappings_del                   [SDT event]
> > [root@jouet ~]# perf record -e sdt_qemu:pci* -a
> > event syntax error: 'sdt_qemu:pci*'
> >                      \___ unknown tracepoint
> > 
> > Error:	File /sys/kernel/debug/tracing/events/sdt_qemu/pci* not found.
> > Hint:	Perhaps this kernel misses some CONFIG_ setting to enable this
> > feature?.
> > 
> > Run 'perf list' for a list of valid events
> > 
> >  Usage: perf record [<options>] [<command>]
> >     or: perf record [<options>] -- <command> [<options>]
> > 
> >     -e, --event <event>   event selector. use 'perf list' to list
> > available events
> > [root@jouet ~]# 
> 
> 
> -- 
> Masami Hiramatsu <mhiramat@kernel.org>